s390: cleanup old instruction decode routines

src/s390/simulator-s390.cc

Index: src/s390/simulator-s390.cc
diff --git a/src/s390/simulator-s390.cc b/src/s390/simulator-s390.cc
index 74a25d53572d4fd5b7e08af3a8312fe05bbfa34d..d387812bd7164097a9a57ad4669171967f60dab2 100644
--- a/src/s390/simulator-s390.cc
+++ b/src/s390/simulator-s390.cc
@@ -2412,3149 +2412,6 @@ void Simulator::PrintStopInfo(uint32_t code) {
 #define CheckOverflowForShiftLeft(src1, src2) \
   (((src1) << (src2)) >> (src2) != (src1))
 
-// S390 Decode and simulate helpers
-bool Simulator::DecodeTwoByte(Instruction* instr) {
-  Opcode op = instr->S390OpcodeValue();
-
-  switch (op) {
-    // RR format instructions
-    case AR:
-    case SR:
-    case MR:
-    case DR:
-    case OR:
-    case NR:
-    case XR: {
-      RRInstruction* rrinst = reinterpret_cast<RRInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      int32_t r1_val = get_low_register<int32_t>(r1);
-      int32_t r2_val = get_low_register<int32_t>(r2);
-      bool isOF = false;
-      switch (op) {
-        case AR:
-          isOF = CheckOverflowForIntAdd(r1_val, r2_val, int32_t);
-          r1_val += r2_val;
-          SetS390ConditionCode<int32_t>(r1_val, 0);
-          SetS390OverflowCode(isOF);
-          break;
-        case SR:
-          isOF = CheckOverflowForIntSub(r1_val, r2_val, int32_t);
-          r1_val -= r2_val;
-          SetS390ConditionCode<int32_t>(r1_val, 0);
-          SetS390OverflowCode(isOF);
-          break;
-        case OR:
-          r1_val |= r2_val;
-          SetS390BitWiseConditionCode<uint32_t>(r1_val);
-          break;
-        case NR:
-          r1_val &= r2_val;
-          SetS390BitWiseConditionCode<uint32_t>(r1_val);
-          break;
-        case XR:
-          r1_val ^= r2_val;
-          SetS390BitWiseConditionCode<uint32_t>(r1_val);
-          break;
-        case MR: {
-          DCHECK(r1 % 2 == 0);
-          r1_val = get_low_register<int32_t>(r1 + 1);
-          int64_t product =
-              static_cast<int64_t>(r1_val) * static_cast<int64_t>(r2_val);
-          int32_t high_bits = product >> 32;
-          r1_val = high_bits;
-          int32_t low_bits = product & 0x00000000FFFFFFFF;
-          set_low_register(r1, high_bits);
-          set_low_register(r1 + 1, low_bits);
-          break;
-        }
-        case DR: {
-          // reg-reg pair should be even-odd pair, assert r1 is an even register
-          DCHECK(r1 % 2 == 0);
-          // leftmost 32 bits of the dividend are in r1
-          // rightmost 32 bits of the dividend are in r1+1
-          // get the signed value from r1
-          int64_t dividend = static_cast<int64_t>(r1_val) << 32;
-          // get unsigned value from r1+1
-          // avoid addition with sign-extended r1+1 value
-          dividend += get_low_register<uint32_t>(r1 + 1);
-          int32_t remainder = dividend % r2_val;
-          int32_t quotient = dividend / r2_val;
-          r1_val = remainder;
-          set_low_register(r1, remainder);
-          set_low_register(r1 + 1, quotient);
-          break;  // reg pair
-        }
-        default:
-          UNREACHABLE();
-          break;
-      }
-      set_low_register(r1, r1_val);
-      break;
-    }
-    case LR: {
-      RRInstruction* rrinst = reinterpret_cast<RRInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      set_low_register(r1, get_low_register<int32_t>(r2));
-      break;
-    }
-    case LDR: {
-      RRInstruction* rrinst = reinterpret_cast<RRInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      int64_t r2_val = get_d_register(r2);
-      set_d_register(r1, r2_val);
-      break;
-    }
-    case CR: {
-      RRInstruction* rrinst = reinterpret_cast<RRInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      int32_t r1_val = get_low_register<int32_t>(r1);
-      int32_t r2_val = get_low_register<int32_t>(r2);
-      SetS390ConditionCode<int32_t>(r1_val, r2_val);
-      break;
-    }
-    case CLR: {
-      RRInstruction* rrinst = reinterpret_cast<RRInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      uint32_t r1_val = get_low_register<uint32_t>(r1);
-      uint32_t r2_val = get_low_register<uint32_t>(r2);
-      SetS390ConditionCode<uint32_t>(r1_val, r2_val);
-      break;
-    }
-    case BCR: {
-      RRInstruction* rrinst = reinterpret_cast<RRInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      if (TestConditionCode(Condition(r1))) {
-        intptr_t r2_val = get_register(r2);
-#if (!V8_TARGET_ARCH_S390X && V8_HOST_ARCH_S390)
-        // On 31-bit, the top most bit may be 0 or 1, but is ignored by the
-        // hardware.  Cleanse the top bit before jumping to it, unless it's one
-        // of the special PCs
-        if (r2_val != bad_lr && r2_val != end_sim_pc) r2_val &= 0x7FFFFFFF;
-#endif
-        set_pc(r2_val);
-      }
-      break;
-    }
-    case LTR: {
-      RRInstruction* rrinst = reinterpret_cast<RRInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      int32_t r2_val = get_low_register<int32_t>(r2);
-      SetS390ConditionCode<int32_t>(r2_val, 0);
-      set_low_register(r1, r2_val);
-      break;
-    }
-    case ALR:
-    case SLR: {
-      RRInstruction* rrinst = reinterpret_cast<RRInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      uint32_t r1_val = get_low_register<uint32_t>(r1);
-      uint32_t r2_val = get_low_register<uint32_t>(r2);
-      uint32_t alu_out = 0;
-      bool isOF = false;
-      if (ALR == op) {
-        alu_out = r1_val + r2_val;
-        isOF = CheckOverflowForUIntAdd(r1_val, r2_val);
-      } else if (SLR == op) {
-        alu_out = r1_val - r2_val;
-        isOF = CheckOverflowForUIntSub(r1_val, r2_val);
-      } else {
-        UNREACHABLE();
-      }
-      set_low_register(r1, alu_out);
-      SetS390ConditionCodeCarry<uint32_t>(alu_out, isOF);
-      break;
-    }
-    case LNR: {
-      // Load Negative (32)
-      RRInstruction* rrinst = reinterpret_cast<RRInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      int32_t r2_val = get_low_register<int32_t>(r2);
-      r2_val = (r2_val >= 0) ? -r2_val : r2_val;  // If pos, then negate it.
-      set_low_register(r1, r2_val);
-      condition_reg_ = (r2_val == 0) ? CC_EQ : CC_LT;  // CC0 - result is zero
-      // CC1 - result is negative
-      break;
-    }
-    case BASR: {
-      RRInstruction* rrinst = reinterpret_cast<RRInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      intptr_t link_addr = get_pc() + 2;
-      // If R2 is zero, the BASR does not branch.
-      int64_t r2_val = (r2 == 0) ? link_addr : get_register(r2);
-#if (!V8_TARGET_ARCH_S390X && V8_HOST_ARCH_S390)
-      // On 31-bit, the top most bit may be 0 or 1, which can cause issues
-      // for stackwalker.  The top bit should either be cleanse before being
-      // pushed onto the stack, or during stack walking when dereferenced.
-      // For simulator, we'll take the worst case scenario and always tag
-      // the high bit, to flush out more problems.
-      link_addr |= 0x80000000;
-#endif
-      set_register(r1, link_addr);
-      set_pc(r2_val);
-      break;
-    }
-    case LCR: {
-      RRInstruction* rrinst = reinterpret_cast<RRInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      int32_t r2_val = get_low_register<int32_t>(r2);
-      int32_t original_r2_val = r2_val;
-      r2_val = ~r2_val;
-      r2_val = r2_val + 1;
-      set_low_register(r1, r2_val);
-      SetS390ConditionCode<int32_t>(r2_val, 0);
-      // Checks for overflow where r2_val = -2147483648.
-      // Cannot do int comparison due to GCC 4.8 bug on x86.
-      // Detect INT_MIN alternatively, as it is the only value where both
-      // original and result are negative due to overflow.
-      if (r2_val < 0 && original_r2_val < 0) {
-        SetS390OverflowCode(true);
-      }
-      break;
-    }
-    case BKPT: {
-      set_pc(get_pc() + 2);
-      S390Debugger dbg(this);
-      dbg.Debug();
-      break;
-    }
-    default:
-      UNREACHABLE();
-      return false;
-      break;
-  }
-  return true;
-}
-
-// Decode routine for four-byte instructions
-bool Simulator::DecodeFourByte(Instruction* instr) {
-  Opcode op = instr->S390OpcodeValue();
-
-  // Pre-cast instruction to various types
-  RREInstruction* rreInst = reinterpret_cast<RREInstruction*>(instr);
-  SIInstruction* siInstr = reinterpret_cast<SIInstruction*>(instr);
-
-  switch (op) {
-    case POPCNT_Z: {
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-      int64_t r2_val = get_register(r2);
-      int64_t r1_val = 0;
-
-      uint8_t* r2_val_ptr = reinterpret_cast<uint8_t*>(&r2_val);
-      uint8_t* r1_val_ptr = reinterpret_cast<uint8_t*>(&r1_val);
-      for (int i = 0; i < 8; i++) {
-        uint32_t x = static_cast<uint32_t>(r2_val_ptr[i]);
-#if defined(__GNUC__)
-        r1_val_ptr[i] = __builtin_popcount(x);
-#else
-#error unsupport __builtin_popcount
-#endif
-      }
-
-      set_register(r1, static_cast<uint64_t>(r1_val));
-      break;
-    }
-    case LLGFR: {
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-      int32_t r2_val = get_low_register<int32_t>(r2);
-      uint64_t r2_finalval =
-          (static_cast<uint64_t>(r2_val) & 0x00000000ffffffff);
-      set_register(r1, r2_finalval);
-      break;
-    }
-    case EX: {
-      RXInstruction* rxinst = reinterpret_cast<RXInstruction*>(instr);
-      int r1 = rxinst->R1Value();
-      int b2 = rxinst->B2Value();
-      int x2 = rxinst->X2Value();
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxinst->D2Value();
-      int32_t r1_val = get_low_register<int32_t>(r1);
-
-      SixByteInstr the_instr = Instruction::InstructionBits(
-          reinterpret_cast<const byte*>(b2_val + x2_val + d2_val));
-      int length = Instruction::InstructionLength(
-          reinterpret_cast<const byte*>(b2_val + x2_val + d2_val));
-
-      char new_instr_buf[8];
-      char* addr = reinterpret_cast<char*>(&new_instr_buf[0]);
-      the_instr |= static_cast<SixByteInstr>(r1_val & 0xff)
-                   << (8 * length - 16);
-      Instruction::SetInstructionBits<SixByteInstr>(
-          reinterpret_cast<byte*>(addr), static_cast<SixByteInstr>(the_instr));
-      ExecuteInstruction(reinterpret_cast<Instruction*>(addr), false);
-      break;
-    }
-    case LGR: {
-      // Load Register (64)
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-      set_register(r1, get_register(r2));
-      break;
-    }
-    case LDGR: {
-      // Load FPR from GPR (L <- 64)
-      uint64_t int_val = get_register(rreInst->R2Value());
-      // double double_val = bit_cast<double, uint64_t>(int_val);
-      // set_d_register_from_double(rreInst->R1Value(), double_val);
-      set_d_register(rreInst->R1Value(), int_val);
-      break;
-    }
-    case LGDR: {
-      // Load GPR from FPR (64 <- L)
-      int64_t double_val = get_d_register(rreInst->R2Value());
-      set_register(rreInst->R1Value(), double_val);
-      break;
-    }
-    case LTGR: {
-      // Load Register (64)
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-      int64_t r2_val = get_register(r2);
-      SetS390ConditionCode<int64_t>(r2_val, 0);
-      set_register(r1, get_register(r2));
-      break;
-    }
-    case LZDR: {
-      int r1 = rreInst->R1Value();
-      set_d_register_from_double(r1, 0.0);
-      break;
-    }
-    case LTEBR: {
-      RREInstruction* rreinst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreinst->R1Value();
-      int r2 = rreinst->R2Value();
-      int64_t r2_val = get_d_register(r2);
-      float fr2_val = get_float32_from_d_register(r2);
-      SetS390ConditionCode<float>(fr2_val, 0.0);
-      set_d_register(r1, r2_val);
-      break;
-    }
-    case LTDBR: {
-      RREInstruction* rreinst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreinst->R1Value();
-      int r2 = rreinst->R2Value();
-      int64_t r2_val = get_d_register(r2);
-      SetS390ConditionCode<double>(bit_cast<double, int64_t>(r2_val), 0.0);
-      set_d_register(r1, r2_val);
-      break;
-    }
-    case CGR: {
-      // Compare (64)
-      int64_t r1_val = get_register(rreInst->R1Value());
-      int64_t r2_val = get_register(rreInst->R2Value());
-      SetS390ConditionCode<int64_t>(r1_val, r2_val);
-      break;
-    }
-    case CLGR: {
-      // Compare Logical (64)
-      uint64_t r1_val = static_cast<uint64_t>(get_register(rreInst->R1Value()));
-      uint64_t r2_val = static_cast<uint64_t>(get_register(rreInst->R2Value()));
-      SetS390ConditionCode<uint64_t>(r1_val, r2_val);
-      break;
-    }
-    case LH: {
-      // Load Halfword
-      RXInstruction* rxinst = reinterpret_cast<RXInstruction*>(instr);
-      int r1 = rxinst->R1Value();
-      int x2 = rxinst->X2Value();
-      int b2 = rxinst->B2Value();
-
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      intptr_t d2_val = rxinst->D2Value();
-      intptr_t mem_addr = x2_val + b2_val + d2_val;
-
-      int32_t result = static_cast<int32_t>(ReadH(mem_addr, instr));
-      set_low_register(r1, result);
-      break;
-    }
-    case LHI: {
-      RIInstruction* riinst = reinterpret_cast<RIInstruction*>(instr);
-      int r1 = riinst->R1Value();
-      int i = riinst->I2Value();
-      set_low_register(r1, i);
-      break;
-    }
-    case LGHI: {
-      RIInstruction* riinst = reinterpret_cast<RIInstruction*>(instr);
-      int r1 = riinst->R1Value();
-      int64_t i = riinst->I2Value();
-      set_register(r1, i);
-      break;
-    }
-    case CHI: {
-      RIInstruction* riinst = reinterpret_cast<RIInstruction*>(instr);
-      int r1 = riinst->R1Value();
-      int16_t i = riinst->I2Value();
-      int32_t r1_val = get_low_register<int32_t>(r1);
-      SetS390ConditionCode<int32_t>(r1_val, i);
-      break;
-    }
-    case CGHI: {
-      RIInstruction* riinst = reinterpret_cast<RIInstruction*>(instr);
-      int r1 = riinst->R1Value();
-      int64_t i = static_cast<int64_t>(riinst->I2Value());
-      int64_t r1_val = get_register(r1);
-      SetS390ConditionCode<int64_t>(r1_val, i);
-      break;
-    }
-    case BRAS: {
-      // Branch Relative and Save
-      RILInstruction* rilInstr = reinterpret_cast<RILInstruction*>(instr);
-      int r1 = rilInstr->R1Value();
-      intptr_t d2 = rilInstr->I2Value();
-      intptr_t pc = get_pc();
-      // Set PC of next instruction to register
-      set_register(r1, pc + sizeof(FourByteInstr));
-      // Update PC to branch target
-      set_pc(pc + d2 * 2);
-      break;
-    }
-    case BRC: {
-      // Branch Relative on Condition
-      RIInstruction* riinst = reinterpret_cast<RIInstruction*>(instr);
-      int m1 = riinst->M1Value();
-      if (TestConditionCode((Condition)m1)) {
-        intptr_t offset = riinst->I2Value() * 2;
-        set_pc(get_pc() + offset);
-      }
-      break;
-    }
-    case BRCT:
-    case BRCTG: {
-      // Branch On Count (32/64).
-      RIInstruction* riinst = reinterpret_cast<RIInstruction*>(instr);
-      int r1 = riinst->R1Value();
-      int64_t value =
-          (op == BRCT) ? get_low_register<int32_t>(r1) : get_register(r1);
-      if (BRCT == op)
-        set_low_register(r1, --value);
-      else
-        set_register(r1, --value);
-      // Branch if value != 0
-      if (value != 0) {
-        intptr_t offset = riinst->I2Value() * 2;
-        set_pc(get_pc() + offset);
-      }
-      break;
-    }
-    case BXH: {
-      RSInstruction* rsinst = reinterpret_cast<RSInstruction*>(instr);
-      int r1 = rsinst->R1Value();
-      int r3 = rsinst->R3Value();
-      int b2 = rsinst->B2Value();
-      int d2 = rsinst->D2Value();
-
-      // r1_val is the first operand, r3_val is the increment
-      int32_t r1_val = r1 == 0 ? 0 : get_register(r1);
-      int32_t r3_val = r2 == 0 ? 0 : get_register(r3);
-      intptr_t b2_val = b2 == 0 ? 0 : get_register(b2);
-      intptr_t branch_address = b2_val + d2;
-      // increment r1_val
-      r1_val += r3_val;
-
-      // if the increment is even, then it designates a pair of registers
-      // and the contents of the even and odd registers of the pair are used as
-      // the increment and compare value respectively. If the increment is odd,
-      // the increment itself is used as both the increment and compare value
-      int32_t compare_val = r3 % 2 == 0 ? get_register(r3 + 1) : r3_val;
-      if (r1_val > compare_val) {
-        // branch to address if r1_val is greater than compare value
-        set_pc(branch_address);
-      }
-
-      // update contents of register in r1 with the new incremented value
-      set_register(r1, r1_val);
-      break;
-    }
-    case IIHH:
-    case IIHL:
-    case IILH:
-    case IILL: {
-      UNIMPLEMENTED();
-      break;
-    }
-    case STM:
-    case LM: {
-      // Store Multiple 32-bits.
-      RSInstruction* rsinstr = reinterpret_cast<RSInstruction*>(instr);
-      int r1 = rsinstr->R1Value();
-      int r3 = rsinstr->R3Value();
-      int rb = rsinstr->B2Value();
-      int offset = rsinstr->D2Value();
-
-      // Regs roll around if r3 is less than r1.
-      // Artifically increase r3 by 16 so we can calculate
-      // the number of regs stored properly.
-      if (r3 < r1) r3 += 16;
-
-      int32_t rb_val = (rb == 0) ? 0 : get_low_register<int32_t>(rb);
-
-      // Store each register in ascending order.
-      for (int i = 0; i <= r3 - r1; i++) {
-        if (op == STM) {
-          int32_t value = get_low_register<int32_t>((r1 + i) % 16);
-          WriteW(rb_val + offset + 4 * i, value, instr);
-        } else if (op == LM) {
-          int32_t value = ReadW(rb_val + offset + 4 * i, instr);
-          set_low_register((r1 + i) % 16, value);
-        }
-      }
-      break;
-    }
-    case SLL:
-    case SRL: {
-      RSInstruction* rsInstr = reinterpret_cast<RSInstruction*>(instr);
-      int r1 = rsInstr->R1Value();
-      int b2 = rsInstr->B2Value();
-      intptr_t d2 = rsInstr->D2Value();
-      // only takes rightmost 6bits
-      int64_t b2_val = b2 == 0 ? 0 : get_register(b2);
-      int shiftBits = (b2_val + d2) & 0x3F;
-      uint32_t r1_val = get_low_register<uint32_t>(r1);
-      uint32_t alu_out = 0;
-      if (SLL == op) {
-        alu_out = r1_val << shiftBits;
-      } else if (SRL == op) {
-        alu_out = r1_val >> shiftBits;
-      } else {
-        UNREACHABLE();
-      }
-      set_low_register(r1, alu_out);
-      break;
-    }
-    case SLDL: {
-      RSInstruction* rsInstr = reinterpret_cast<RSInstruction*>(instr);
-      int r1 = rsInstr->R1Value();
-      int b2 = rsInstr->B2Value();
-      intptr_t d2 = rsInstr->D2Value();
-      // only takes rightmost 6bits
-      int64_t b2_val = b2 == 0 ? 0 : get_register(b2);
-      int shiftBits = (b2_val + d2) & 0x3F;
-
-      DCHECK(r1 % 2 == 0);
-      uint32_t r1_val = get_low_register<uint32_t>(r1);
-      uint32_t r1_next_val = get_low_register<uint32_t>(r1 + 1);
-      uint64_t alu_out = (static_cast<uint64_t>(r1_val) << 32) |
-                         (static_cast<uint64_t>(r1_next_val));
-      alu_out <<= shiftBits;
-      set_low_register(r1 + 1, static_cast<uint32_t>(alu_out));
-      set_low_register(r1, static_cast<uint32_t>(alu_out >> 32));
-      break;
-    }
-    case SLA:
-    case SRA: {
-      RSInstruction* rsInstr = reinterpret_cast<RSInstruction*>(instr);
-      int r1 = rsInstr->R1Value();
-      int b2 = rsInstr->B2Value();
-      intptr_t d2 = rsInstr->D2Value();
-      // only takes rightmost 6bits
-      int64_t b2_val = b2 == 0 ? 0 : get_register(b2);
-      int shiftBits = (b2_val + d2) & 0x3F;
-      int32_t r1_val = get_low_register<int32_t>(r1);
-      int32_t alu_out = 0;
-      bool isOF = false;
-      if (op == SLA) {
-        isOF = CheckOverflowForShiftLeft(r1_val, shiftBits);
-        alu_out = r1_val << shiftBits;
-      } else if (op == SRA) {
-        alu_out = r1_val >> shiftBits;
-      }
-      set_low_register(r1, alu_out);
-      SetS390ConditionCode<int32_t>(alu_out, 0);
-      SetS390OverflowCode(isOF);
-      break;
-    }
-    case LLHR: {
-      UNIMPLEMENTED();
-      break;
-    }
-    case LLGHR: {
-      UNIMPLEMENTED();
-      break;
-    }
-    case L:
-    case LA:
-    case LD:
-    case LE: {
-      RXInstruction* rxinst = reinterpret_cast<RXInstruction*>(instr);
-      int b2 = rxinst->B2Value();
-      int x2 = rxinst->X2Value();
-      int32_t r1 = rxinst->R1Value();
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxinst->D2Value();
-      intptr_t addr = b2_val + x2_val + d2_val;
-      if (op == L) {
-        int32_t mem_val = ReadW(addr, instr);
-        set_low_register(r1, mem_val);
-      } else if (op == LA) {
-        set_register(r1, addr);
-      } else if (op == LD) {
-        int64_t dbl_val = *reinterpret_cast<int64_t*>(addr);
-        set_d_register(r1, dbl_val);
-      } else if (op == LE) {
-        float float_val = *reinterpret_cast<float*>(addr);
-        set_d_register_from_float32(r1, float_val);
-      }
-      break;
-    }
-    case C:
-    case CL: {
-      RXInstruction* rxinst = reinterpret_cast<RXInstruction*>(instr);
-      int b2 = rxinst->B2Value();
-      int x2 = rxinst->X2Value();
-      int32_t r1_val = get_low_register<int32_t>(rxinst->R1Value());
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxinst->D2Value();
-      intptr_t addr = b2_val + x2_val + d2_val;
-      int32_t mem_val = ReadW(addr, instr);
-      if (C == op)
-        SetS390ConditionCode<int32_t>(r1_val, mem_val);
-      else if (CL == op)
-        SetS390ConditionCode<uint32_t>(r1_val, mem_val);
-      break;
-    }
-    case CLI: {
-      // Compare Immediate (Mem - Imm) (8)
-      int b1 = siInstr->B1Value();
-      int64_t b1_val = (b1 == 0) ? 0 : get_register(b1);
-      intptr_t d1_val = siInstr->D1Value();
-      intptr_t addr = b1_val + d1_val;
-      uint8_t mem_val = ReadB(addr);
-      uint8_t imm_val = siInstr->I2Value();
-      SetS390ConditionCode<uint8_t>(mem_val, imm_val);
-      break;
-    }
-    case TM: {
-      // Test Under Mask (Mem - Imm) (8)
-      int b1 = siInstr->B1Value();
-      int64_t b1_val = (b1 == 0) ? 0 : get_register(b1);
-      intptr_t d1_val = siInstr->D1Value();
-      intptr_t addr = b1_val + d1_val;
-      uint8_t mem_val = ReadB(addr);
-      uint8_t imm_val = siInstr->I2Value();
-      uint8_t selected_bits = mem_val & imm_val;
-      // CC0: Selected bits are zero
-      // CC1: Selected bits mixed zeros and ones
-      // CC3: Selected bits all ones
-      if (0 == selected_bits) {
-        condition_reg_ = CC_EQ;  // CC0
-      } else if (selected_bits == imm_val) {
-        condition_reg_ = 0x1;  // CC3
-      } else {
-        condition_reg_ = 0x4;  // CC1
-      }
-      break;
-    }
-    case ST:
-    case STE:
-    case STD: {
-      RXInstruction* rxinst = reinterpret_cast<RXInstruction*>(instr);
-      int b2 = rxinst->B2Value();
-      int x2 = rxinst->X2Value();
-      int32_t r1_val = get_low_register<int32_t>(rxinst->R1Value());
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxinst->D2Value();
-      intptr_t addr = b2_val + x2_val + d2_val;
-      if (op == ST) {
-        WriteW(addr, r1_val, instr);
-      } else if (op == STD) {
-        int64_t frs_val = get_d_register(rxinst->R1Value());
-        WriteDW(addr, frs_val);
-      } else if (op == STE) {
-        int64_t frs_val = get_d_register(rxinst->R1Value()) >> 32;
-        WriteW(addr, static_cast<int32_t>(frs_val), instr);
-      }
-      break;
-    }
-    case LTGFR:
-    case LGFR: {
-      // Load and Test Register (64 <- 32)  (Sign Extends 32-bit val)
-      // Load Register (64 <- 32)  (Sign Extends 32-bit val)
-      RREInstruction* rreInstr = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreInstr->R1Value();
-      int r2 = rreInstr->R2Value();
-      int32_t r2_val = get_low_register<int32_t>(r2);
-      int64_t result = static_cast<int64_t>(r2_val);
-      set_register(r1, result);
-
-      if (LTGFR == op) SetS390ConditionCode<int64_t>(result, 0);
-      break;
-    }
-    case LNGR: {
-      // Load Negative (64)
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-      int64_t r2_val = get_register(r2);
-      r2_val = (r2_val >= 0) ? -r2_val : r2_val;  // If pos, then negate it.
-      set_register(r1, r2_val);
-      condition_reg_ = (r2_val == 0) ? CC_EQ : CC_LT;  // CC0 - result is zero
-      // CC1 - result is negative
-      break;
-    }
-    case TRAP4: {
-      // whack the space of the caller allocated stack
-      int64_t sp_addr = get_register(sp);
-      for (int i = 0; i < kCalleeRegisterSaveAreaSize / kPointerSize; ++i) {
-        // we dont want to whack the RA (r14)
-        if (i != 14) (reinterpret_cast<intptr_t*>(sp_addr))[i] = 0xdeadbabe;
-      }
-      SoftwareInterrupt(instr);
-      break;
-    }
-    case STC: {
-      // Store Character/Byte
-      RXInstruction* rxinst = reinterpret_cast<RXInstruction*>(instr);
-      int b2 = rxinst->B2Value();
-      int x2 = rxinst->X2Value();
-      uint8_t r1_val = get_low_register<int32_t>(rxinst->R1Value());
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxinst->D2Value();
-      intptr_t mem_addr = b2_val + x2_val + d2_val;
-      WriteB(mem_addr, r1_val);
-      break;
-    }
-    case STH: {
-      RXInstruction* rxinst = reinterpret_cast<RXInstruction*>(instr);
-      int b2 = rxinst->B2Value();
-      int x2 = rxinst->X2Value();
-      int16_t r1_val = get_low_register<int32_t>(rxinst->R1Value());
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxinst->D2Value();
-      intptr_t mem_addr = b2_val + x2_val + d2_val;
-      WriteH(mem_addr, r1_val, instr);
-      break;
-    }
-#if V8_TARGET_ARCH_S390X
-    case LCGR: {
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-      int64_t r2_val = get_register(r2);
-      r2_val = ~r2_val;
-      r2_val = r2_val + 1;
-      set_register(r1, r2_val);
-      SetS390ConditionCode<int64_t>(r2_val, 0);
-      // if the input is INT_MIN, loading its compliment would be overflowing
-      if (r2_val < 0 && (r2_val + 1) > 0) {
-        SetS390OverflowCode(true);
-      }
-      break;
-    }
-#endif
-    case SRDA: {
-      RSInstruction* rsInstr = reinterpret_cast<RSInstruction*>(instr);
-      int r1 = rsInstr->R1Value();
-      DCHECK(r1 % 2 == 0);  // must be a reg pair
-      int b2 = rsInstr->B2Value();
-      intptr_t d2 = rsInstr->D2Value();
-      // only takes rightmost 6bits
-      int64_t b2_val = b2 == 0 ? 0 : get_register(b2);
-      int shiftBits = (b2_val + d2) & 0x3F;
-      int64_t opnd1 = static_cast<int64_t>(get_low_register<int32_t>(r1)) << 32;
-      int64_t opnd2 = static_cast<uint64_t>(get_low_register<uint32_t>(r1 + 1));
-      int64_t r1_val = opnd1 + opnd2;
-      int64_t alu_out = r1_val >> shiftBits;
-      set_low_register(r1, alu_out >> 32);
-      set_low_register(r1 + 1, alu_out & 0x00000000FFFFFFFF);
-      SetS390ConditionCode<int32_t>(alu_out, 0);
-      break;
-    }
-    case SRDL: {
-      RSInstruction* rsInstr = reinterpret_cast<RSInstruction*>(instr);
-      int r1 = rsInstr->R1Value();
-      DCHECK(r1 % 2 == 0);  // must be a reg pair
-      int b2 = rsInstr->B2Value();
-      intptr_t d2 = rsInstr->D2Value();
-      // only takes rightmost 6bits
-      int64_t b2_val = b2 == 0 ? 0 : get_register(b2);
-      int shiftBits = (b2_val + d2) & 0x3F;
-      uint64_t opnd1 = static_cast<uint64_t>(get_low_register<uint32_t>(r1))
-                       << 32;
-      uint64_t opnd2 =
-          static_cast<uint64_t>(get_low_register<uint32_t>(r1 + 1));
-      uint64_t r1_val = opnd1 | opnd2;
-      uint64_t alu_out = r1_val >> shiftBits;
-      set_low_register(r1, alu_out >> 32);
-      set_low_register(r1 + 1, alu_out & 0x00000000FFFFFFFF);
-      SetS390ConditionCode<int32_t>(alu_out, 0);
-      break;
-    }
-    default: { return DecodeFourByteArithmetic(instr); }
-  }
-  return true;
-}
-
-bool Simulator::DecodeFourByteArithmetic64Bit(Instruction* instr) {
-  Opcode op = instr->S390OpcodeValue();
-
-  RRFInstruction* rrfInst = reinterpret_cast<RRFInstruction*>(instr);
-  RREInstruction* rreInst = reinterpret_cast<RREInstruction*>(instr);
-
-  switch (op) {
-    case AGR:
-    case SGR:
-    case OGR:
-    case NGR:
-    case XGR: {
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-      int64_t r1_val = get_register(r1);
-      int64_t r2_val = get_register(r2);
-      bool isOF = false;
-      switch (op) {
-        case AGR:
-          isOF = CheckOverflowForIntAdd(r1_val, r2_val, int64_t);
-          r1_val += r2_val;
-          SetS390ConditionCode<int64_t>(r1_val, 0);
-          SetS390OverflowCode(isOF);
-          break;
-        case SGR:
-          isOF = CheckOverflowForIntSub(r1_val, r2_val, int64_t);
-          r1_val -= r2_val;
-          SetS390ConditionCode<int64_t>(r1_val, 0);
-          SetS390OverflowCode(isOF);
-          break;
-        case OGR:
-          r1_val |= r2_val;
-          SetS390BitWiseConditionCode<uint64_t>(r1_val);
-          break;
-        case NGR:
-          r1_val &= r2_val;
-          SetS390BitWiseConditionCode<uint64_t>(r1_val);
-          break;
-        case XGR:
-          r1_val ^= r2_val;
-          SetS390BitWiseConditionCode<uint64_t>(r1_val);
-          break;
-        default:
-          UNREACHABLE();
-          break;
-      }
-      set_register(r1, r1_val);
-      break;
-    }
-    case AGFR: {
-      // Add Register (64 <- 32)  (Sign Extends 32-bit val)
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-      int64_t r1_val = get_register(r1);
-      int64_t r2_val = static_cast<int64_t>(get_low_register<int32_t>(r2));
-      bool isOF = CheckOverflowForIntAdd(r1_val, r2_val, int64_t);
-      r1_val += r2_val;
-      SetS390ConditionCode<int64_t>(r1_val, 0);
-      SetS390OverflowCode(isOF);
-      set_register(r1, r1_val);
-      break;
-    }
-    case SGFR: {
-      // Sub Reg (64 <- 32)
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-      int64_t r1_val = get_register(r1);
-      int64_t r2_val = static_cast<int64_t>(get_low_register<int32_t>(r2));
-      bool isOF = false;
-      isOF = CheckOverflowForIntSub(r1_val, r2_val, int64_t);
-      r1_val -= r2_val;
-      SetS390ConditionCode<int64_t>(r1_val, 0);
-      SetS390OverflowCode(isOF);
-      set_register(r1, r1_val);
-      break;
-    }
-    case AGRK:
-    case SGRK:
-    case NGRK:
-    case OGRK:
-    case XGRK: {
-      // 64-bit Non-clobbering arithmetics / bitwise ops.
-      int r1 = rrfInst->R1Value();
-      int r2 = rrfInst->R2Value();
-      int r3 = rrfInst->R3Value();
-      int64_t r2_val = get_register(r2);
-      int64_t r3_val = get_register(r3);
-      if (AGRK == op) {
-        bool isOF = CheckOverflowForIntAdd(r2_val, r3_val, int64_t);
-        SetS390ConditionCode<int64_t>(r2_val + r3_val, 0);
-        SetS390OverflowCode(isOF);
-        set_register(r1, r2_val + r3_val);
-      } else if (SGRK == op) {
-        bool isOF = CheckOverflowForIntSub(r2_val, r3_val, int64_t);
-        SetS390ConditionCode<int64_t>(r2_val - r3_val, 0);
-        SetS390OverflowCode(isOF);
-        set_register(r1, r2_val - r3_val);
-      } else {
-        // Assume bitwise operation here
-        uint64_t bitwise_result = 0;
-        if (NGRK == op) {
-          bitwise_result = r2_val & r3_val;
-        } else if (OGRK == op) {
-          bitwise_result = r2_val | r3_val;
-        } else if (XGRK == op) {
-          bitwise_result = r2_val ^ r3_val;
-        }
-        SetS390BitWiseConditionCode<uint64_t>(bitwise_result);
-        set_register(r1, bitwise_result);
-      }
-      break;
-    }
-    case ALGRK:
-    case SLGRK: {
-      // 64-bit Non-clobbering unsigned arithmetics
-      int r1 = rrfInst->R1Value();
-      int r2 = rrfInst->R2Value();
-      int r3 = rrfInst->R3Value();
-      uint64_t r2_val = get_register(r2);
-      uint64_t r3_val = get_register(r3);
-      if (ALGRK == op) {
-        bool isOF = CheckOverflowForUIntAdd(r2_val, r3_val);
-        SetS390ConditionCode<uint64_t>(r2_val + r3_val, 0);
-        SetS390OverflowCode(isOF);
-        set_register(r1, r2_val + r3_val);
-      } else if (SLGRK == op) {
-        bool isOF = CheckOverflowForUIntSub(r2_val, r3_val);
-        SetS390ConditionCode<uint64_t>(r2_val - r3_val, 0);
-        SetS390OverflowCode(isOF);
-        set_register(r1, r2_val - r3_val);
-      }
-      break;
-    }
-    case AGHI:
-    case MGHI: {
-      RIInstruction* riinst = reinterpret_cast<RIInstruction*>(instr);
-      int32_t r1 = riinst->R1Value();
-      int64_t i = static_cast<int64_t>(riinst->I2Value());
-      int64_t r1_val = get_register(r1);
-      bool isOF = false;
-      switch (op) {
-        case AGHI:
-          isOF = CheckOverflowForIntAdd(r1_val, i, int64_t);
-          r1_val += i;
-          break;
-        case MGHI:
-          isOF = CheckOverflowForMul(r1_val, i);
-          r1_val *= i;
-          break;  // no overflow indication is given
-        default:
-          break;
-      }
-      set_register(r1, r1_val);
-      SetS390ConditionCode<int32_t>(r1_val, 0);
-      SetS390OverflowCode(isOF);
-      break;
-    }
-    default:
-      UNREACHABLE();
-  }
-  return true;
-}
-
-/**
- * Decodes and simulates four byte arithmetic instructions
- */
-bool Simulator::DecodeFourByteArithmetic(Instruction* instr) {
-  Opcode op = instr->S390OpcodeValue();
-
-  // Pre-cast instruction to various types
-  RRFInstruction* rrfInst = reinterpret_cast<RRFInstruction*>(instr);
-
-  switch (op) {
-    case AGR:
-    case SGR:
-    case OGR:
-    case NGR:
-    case XGR:
-    case AGFR:
-    case SGFR: {
-      DecodeFourByteArithmetic64Bit(instr);
-      break;
-    }
-    case ARK:
-    case SRK:
-    case NRK:
-    case ORK:
-    case XRK: {
-      // 32-bit Non-clobbering arithmetics / bitwise ops
-      int r1 = rrfInst->R1Value();
-      int r2 = rrfInst->R2Value();
-      int r3 = rrfInst->R3Value();
-      int32_t r2_val = get_low_register<int32_t>(r2);
-      int32_t r3_val = get_low_register<int32_t>(r3);
-      if (ARK == op) {
-        bool isOF = CheckOverflowForIntAdd(r2_val, r3_val, int32_t);
-        SetS390ConditionCode<int32_t>(r2_val + r3_val, 0);
-        SetS390OverflowCode(isOF);
-        set_low_register(r1, r2_val + r3_val);
-      } else if (SRK == op) {
-        bool isOF = CheckOverflowForIntSub(r2_val, r3_val, int32_t);
-        SetS390ConditionCode<int32_t>(r2_val - r3_val, 0);
-        SetS390OverflowCode(isOF);
-        set_low_register(r1, r2_val - r3_val);
-      } else {
-        // Assume bitwise operation here
-        uint32_t bitwise_result = 0;
-        if (NRK == op) {
-          bitwise_result = r2_val & r3_val;
-        } else if (ORK == op) {
-          bitwise_result = r2_val | r3_val;
-        } else if (XRK == op) {
-          bitwise_result = r2_val ^ r3_val;
-        }
-        SetS390BitWiseConditionCode<uint32_t>(bitwise_result);
-        set_low_register(r1, bitwise_result);
-      }
-      break;
-    }
-    case ALRK:
-    case SLRK: {
-      // 32-bit Non-clobbering unsigned arithmetics
-      int r1 = rrfInst->R1Value();
-      int r2 = rrfInst->R2Value();
-      int r3 = rrfInst->R3Value();
-      uint32_t r2_val = get_low_register<uint32_t>(r2);
-      uint32_t r3_val = get_low_register<uint32_t>(r3);
-      if (ALRK == op) {
-        bool isOF = CheckOverflowForUIntAdd(r2_val, r3_val);
-        SetS390ConditionCode<uint32_t>(r2_val + r3_val, 0);
-        SetS390OverflowCode(isOF);
-        set_low_register(r1, r2_val + r3_val);
-      } else if (SLRK == op) {
-        bool isOF = CheckOverflowForUIntSub(r2_val, r3_val);
-        SetS390ConditionCode<uint32_t>(r2_val - r3_val, 0);
-        SetS390OverflowCode(isOF);
-        set_low_register(r1, r2_val - r3_val);
-      }
-      break;
-    }
-    case AGRK:
-    case SGRK:
-    case NGRK:
-    case OGRK:
-    case XGRK: {
-      DecodeFourByteArithmetic64Bit(instr);
-      break;
-    }
-    case ALGRK:
-    case SLGRK: {
-      DecodeFourByteArithmetic64Bit(instr);
-      break;
-    }
-    case AHI:
-    case MHI: {
-      RIInstruction* riinst = reinterpret_cast<RIInstruction*>(instr);
-      int32_t r1 = riinst->R1Value();
-      int32_t i = riinst->I2Value();
-      int32_t r1_val = get_low_register<int32_t>(r1);
-      bool isOF = false;
-      switch (op) {
-        case AHI:
-          isOF = CheckOverflowForIntAdd(r1_val, i, int32_t);
-          r1_val += i;
-          break;
-        case MHI:
-          isOF = CheckOverflowForMul(r1_val, i);
-          r1_val *= i;
-          break;  // no overflow indication is given
-        default:
-          break;
-      }
-      set_low_register(r1, r1_val);
-      SetS390ConditionCode<int32_t>(r1_val, 0);
-      SetS390OverflowCode(isOF);
-      break;
-    }
-    case AGHI:
-    case MGHI: {
-      DecodeFourByteArithmetic64Bit(instr);
-      break;
-    }
-    case MLR: {
-      RREInstruction* rreinst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreinst->R1Value();
-      int r2 = rreinst->R2Value();
-      DCHECK(r1 % 2 == 0);
-
-      uint32_t r1_val = get_low_register<uint32_t>(r1 + 1);
-      uint32_t r2_val = get_low_register<uint32_t>(r2);
-      uint64_t product =
-          static_cast<uint64_t>(r1_val) * static_cast<uint64_t>(r2_val);
-      int32_t high_bits = product >> 32;
-      int32_t low_bits = product & 0x00000000FFFFFFFF;
-      set_low_register(r1, high_bits);
-      set_low_register(r1 + 1, low_bits);
-      break;
-    }
-    case DLGR: {
-#ifdef V8_TARGET_ARCH_S390X
-      RREInstruction* rreinst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreinst->R1Value();
-      int r2 = rreinst->R2Value();
-      uint64_t r1_val = get_register(r1);
-      uint64_t r2_val = get_register(r2);
-      DCHECK(r1 % 2 == 0);
-      unsigned __int128 dividend = static_cast<unsigned __int128>(r1_val) << 64;
-      dividend += get_register(r1 + 1);
-      uint64_t remainder = dividend % r2_val;
-      uint64_t quotient = dividend / r2_val;
-      r1_val = remainder;
-      set_register(r1, remainder);
-      set_register(r1 + 1, quotient);
-#else
-      UNREACHABLE();
-#endif
-      break;
-    }
-    case DLR: {
-      RREInstruction* rreinst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreinst->R1Value();
-      int r2 = rreinst->R2Value();
-      uint32_t r1_val = get_low_register<uint32_t>(r1);
-      uint32_t r2_val = get_low_register<uint32_t>(r2);
-      DCHECK(r1 % 2 == 0);
-      uint64_t dividend = static_cast<uint64_t>(r1_val) << 32;
-      dividend += get_low_register<uint32_t>(r1 + 1);
-      uint32_t remainder = dividend % r2_val;
-      uint32_t quotient = dividend / r2_val;
-      r1_val = remainder;
-      set_low_register(r1, remainder);
-      set_low_register(r1 + 1, quotient);
-      break;
-    }
-    case A:
-    case S:
-    case M:
-    case D:
-    case O:
-    case N:
-    case X: {
-      // 32-bit Reg-Mem instructions
-      RXInstruction* rxinst = reinterpret_cast<RXInstruction*>(instr);
-      int b2 = rxinst->B2Value();
-      int x2 = rxinst->X2Value();
-      int32_t r1_val = get_low_register<int32_t>(rxinst->R1Value());
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxinst->D2Value();
-      int32_t mem_val = ReadW(b2_val + x2_val + d2_val, instr);
-      int32_t alu_out = 0;
-      bool isOF = false;
-      switch (op) {
-        case A:
-          isOF = CheckOverflowForIntAdd(r1_val, mem_val, int32_t);
-          alu_out = r1_val + mem_val;
-          SetS390ConditionCode<int32_t>(alu_out, 0);
-          SetS390OverflowCode(isOF);
-          break;
-        case S:
-          isOF = CheckOverflowForIntSub(r1_val, mem_val, int32_t);
-          alu_out = r1_val - mem_val;
-          SetS390ConditionCode<int32_t>(alu_out, 0);
-          SetS390OverflowCode(isOF);
-          break;
-        case M:
-        case D:
-          UNIMPLEMENTED();
-          break;
-        case O:
-          alu_out = r1_val | mem_val;
-          SetS390BitWiseConditionCode<uint32_t>(alu_out);
-          break;
-        case N:
-          alu_out = r1_val & mem_val;
-          SetS390BitWiseConditionCode<uint32_t>(alu_out);
-          break;
-        case X:
-          alu_out = r1_val ^ mem_val;
-          SetS390BitWiseConditionCode<uint32_t>(alu_out);
-          break;
-        default:
-          UNREACHABLE();
-          break;
-      }
-      set_low_register(r1, alu_out);
-      break;
-    }
-    case OILL:
-    case OIHL: {
-      RIInstruction* riInst = reinterpret_cast<RIInstruction*>(instr);
-      int r1 = riInst->R1Value();
-      int i = riInst->I2Value();
-      int32_t r1_val = get_low_register<int32_t>(r1);
-      if (OILL == op) {
-        // CC is set based on the 16 bits that are AND'd
-        SetS390BitWiseConditionCode<uint16_t>(r1_val | i);
-      } else if (OILH == op) {
-        // CC is set based on the 16 bits that are AND'd
-        SetS390BitWiseConditionCode<uint16_t>((r1_val >> 16) | i);
-        i = i << 16;
-      } else {
-        UNIMPLEMENTED();
-      }
-      set_low_register(r1, r1_val | i);
-      break;
-    }
-    case NILL:
-    case NILH: {
-      RIInstruction* riInst = reinterpret_cast<RIInstruction*>(instr);
-      int r1 = riInst->R1Value();
-      int i = riInst->I2Value();
-      int32_t r1_val = get_low_register<int32_t>(r1);
-      if (NILL == op) {
-        // CC is set based on the 16 bits that are AND'd
-        SetS390BitWiseConditionCode<uint16_t>(r1_val & i);
-        i |= 0xFFFF0000;
-      } else if (NILH == op) {
-        // CC is set based on the 16 bits that are AND'd
-        SetS390BitWiseConditionCode<uint16_t>((r1_val >> 16) & i);
-        i = (i << 16) | 0x0000FFFF;
-      } else {
-        UNIMPLEMENTED();
-      }
-      set_low_register(r1, r1_val & i);
-      break;
-    }
-    case AH:
-    case SH:
-    case MH: {
-      RXInstruction* rxinst = reinterpret_cast<RXInstruction*>(instr);
-      int b2 = rxinst->B2Value();
-      int x2 = rxinst->X2Value();
-      int32_t r1_val = get_low_register<int32_t>(rxinst->R1Value());
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxinst->D2Value();
-      intptr_t addr = b2_val + x2_val + d2_val;
-      int32_t mem_val = static_cast<int32_t>(ReadH(addr, instr));
-      int32_t alu_out = 0;
-      bool isOF = false;
-      if (AH == op) {
-        isOF = CheckOverflowForIntAdd(r1_val, mem_val, int32_t);
-        alu_out = r1_val + mem_val;
-      } else if (SH == op) {
-        isOF = CheckOverflowForIntSub(r1_val, mem_val, int32_t);
-        alu_out = r1_val - mem_val;
-      } else if (MH == op) {
-        alu_out = r1_val * mem_val;
-      } else {
-        UNREACHABLE();
-      }
-      set_low_register(r1, alu_out);
-      if (MH != op) {  // MH does not change condition code
-        SetS390ConditionCode<int32_t>(alu_out, 0);
-        SetS390OverflowCode(isOF);
-      }
-      break;
-    }
-    case DSGR: {
-      RREInstruction* rreInst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-
-      DCHECK(r1 % 2 == 0);
-
-      int64_t dividend = get_register(r1 + 1);
-      int64_t divisor = get_register(r2);
-      set_register(r1, dividend % divisor);
-      set_register(r1 + 1, dividend / divisor);
-
-      break;
-    }
-    case FLOGR: {
-      RREInstruction* rreInst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-
-      DCHECK(r1 % 2 == 0);
-
-      int64_t r2_val = get_register(r2);
-
-      int i = 0;
-      for (; i < 64; i++) {
-        if (r2_val < 0) break;
-        r2_val <<= 1;
-      }
-
-      r2_val = get_register(r2);
-
-      int64_t mask = ~(1 << (63 - i));
-      set_register(r1, i);
-      set_register(r1 + 1, r2_val & mask);
-
-      break;
-    }
-    case MSR:
-    case MSGR: {  // they do not set overflow code
-      RREInstruction* rreInst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-      if (op == MSR) {
-        int32_t r1_val = get_low_register<int32_t>(r1);
-        int32_t r2_val = get_low_register<int32_t>(r2);
-        set_low_register(r1, r1_val * r2_val);
-      } else if (op == MSGR) {
-        int64_t r1_val = get_register(r1);
-        int64_t r2_val = get_register(r2);
-        set_register(r1, r1_val * r2_val);
-      } else {
-        UNREACHABLE();
-      }
-      break;
-    }
-    case MS: {
-      RXInstruction* rxinst = reinterpret_cast<RXInstruction*>(instr);
-      int r1 = rxinst->R1Value();
-      int b2 = rxinst->B2Value();
-      int x2 = rxinst->X2Value();
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      intptr_t d2_val = rxinst->D2Value();
-      int32_t mem_val = ReadW(b2_val + x2_val + d2_val, instr);
-      int32_t r1_val = get_low_register<int32_t>(r1);
-      set_low_register(r1, r1_val * mem_val);
-      break;
-    }
-    case LGBR:
-    case LBR: {
-      RREInstruction* rrinst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      if (op == LGBR) {
-      int64_t r2_val = get_low_register<int64_t>(r2);
-      r2_val <<= 56;
-      r2_val >>= 56;
-      set_register(r1, r2_val);
-      } else if (op == LBR) {
-      int32_t r2_val = get_low_register<int32_t>(r2);
-      r2_val <<= 24;
-      r2_val >>= 24;
-      set_low_register(r1, r2_val);
-      } else {
-        UNREACHABLE();
-      }
-      break;
-    }
-    case LGHR:
-    case LHR: {
-      RREInstruction* rrinst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      if (op == LGHR) {
-      int64_t r2_val = get_low_register<int64_t>(r2);
-      r2_val <<= 48;
-      r2_val >>= 48;
-      set_register(r1, r2_val);
-      } else if (op == LHR) {
-      int32_t r2_val = get_low_register<int32_t>(r2);
-      r2_val <<= 16;
-      r2_val >>= 16;
-      set_low_register(r1, r2_val);
-      } else {
-        UNREACHABLE();
-      }
-      break;
-    }
-    case ALCR: {
-      RREInstruction* rrinst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      uint32_t r1_val = get_low_register<uint32_t>(r1);
-      uint32_t r2_val = get_low_register<uint32_t>(r2);
-      uint32_t alu_out = 0;
-      bool isOF = false;
-
-      alu_out = r1_val + r2_val;
-      bool isOF_original = CheckOverflowForUIntAdd(r1_val, r2_val);
-      if (TestConditionCode((Condition)2) || TestConditionCode((Condition)3)) {
-        alu_out = alu_out + 1;
-        isOF = isOF_original || CheckOverflowForUIntAdd(alu_out, 1);
-      } else {
-        isOF = isOF_original;
-      }
-      set_low_register(r1, alu_out);
-      SetS390ConditionCodeCarry<uint32_t>(alu_out, isOF);
-      break;
-    }
-    case SLBR: {
-      RREInstruction* rrinst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rrinst->R1Value();
-      int r2 = rrinst->R2Value();
-      uint32_t r1_val = get_low_register<uint32_t>(r1);
-      uint32_t r2_val = get_low_register<uint32_t>(r2);
-      uint32_t alu_out = 0;
-      bool isOF = false;
-
-      alu_out = r1_val - r2_val;
-      bool isOF_original = CheckOverflowForUIntSub(r1_val, r2_val);
-      if (TestConditionCode((Condition)2) || TestConditionCode((Condition)3)) {
-        alu_out = alu_out - 1;
-        isOF = isOF_original || CheckOverflowForUIntSub(alu_out, 1);
-      } else {
-        isOF = isOF_original;
-      }
-      set_low_register(r1, alu_out);
-      SetS390ConditionCodeCarry<uint32_t>(alu_out, isOF);
-      break;
-    }
-    default: { return DecodeFourByteFloatingPoint(instr); }
-  }
-  return true;
-}
-
-void Simulator::DecodeFourByteFloatingPointIntConversion(Instruction* instr) {
-  Opcode op = instr->S390OpcodeValue();
-  switch (op) {
-    case CDLFBR:
-    case CDLGBR:
-    case CELGBR:
-    case CLFDBR:
-    case CLGDBR:
-    case CELFBR:
-    case CLGEBR:
-    case CLFEBR: {
-      RREInstruction* rreInstr = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreInstr->R1Value();
-      int r2 = rreInstr->R2Value();
-      if (op == CDLFBR) {
-        uint32_t r2_val = get_low_register<uint32_t>(r2);
-        double r1_val = static_cast<double>(r2_val);
-        set_d_register_from_double(r1, r1_val);
-      } else if (op == CELFBR) {
-        uint32_t r2_val = get_low_register<uint32_t>(r2);
-        float r1_val = static_cast<float>(r2_val);
-        set_d_register_from_float32(r1, r1_val);
-      } else if (op == CDLGBR) {
-        uint64_t r2_val = get_register(r2);
-        double r1_val = static_cast<double>(r2_val);
-        set_d_register_from_double(r1, r1_val);
-      } else if (op == CELGBR) {
-        uint64_t r2_val = get_register(r2);
-        float r1_val = static_cast<float>(r2_val);
-        set_d_register_from_float32(r1, r1_val);
-      } else if (op == CLFDBR) {
-        double r2_val = get_double_from_d_register(r2);
-        uint32_t r1_val = static_cast<uint32_t>(r2_val);
-        set_low_register(r1, r1_val);
-        SetS390ConvertConditionCode<double>(r2_val, r1_val, UINT32_MAX);
-      } else if (op == CLFEBR) {
-        float r2_val = get_float32_from_d_register(r2);
-        uint32_t r1_val = static_cast<uint32_t>(r2_val);
-        set_low_register(r1, r1_val);
-        SetS390ConvertConditionCode<double>(r2_val, r1_val, UINT32_MAX);
-      } else if (op == CLGDBR) {
-        double r2_val = get_double_from_d_register(r2);
-        uint64_t r1_val = static_cast<uint64_t>(r2_val);
-        set_register(r1, r1_val);
-        SetS390ConvertConditionCode<double>(r2_val, r1_val, UINT64_MAX);
-      } else if (op == CLGEBR) {
-        float r2_val = get_float32_from_d_register(r2);
-        uint64_t r1_val = static_cast<uint64_t>(r2_val);
-        set_register(r1, r1_val);
-        SetS390ConvertConditionCode<double>(r2_val, r1_val, UINT64_MAX);
-      }
-      break;
-    }
-    default:
-      UNREACHABLE();
-  }
-}
-
-void Simulator::DecodeFourByteFloatingPointRound(Instruction* instr) {
-  Opcode op = instr->S390OpcodeValue();
-  RREInstruction* rreInstr = reinterpret_cast<RREInstruction*>(instr);
-  int r1 = rreInstr->R1Value();
-  int r2 = rreInstr->R2Value();
-  double r2_val = get_double_from_d_register(r2);
-  float r2_fval = get_float32_from_d_register(r2);
-
-  switch (op) {
-    case CFDBR: {
-      int mask_val = rreInstr->M3Value();
-      int32_t r1_val = 0;
-
-      SetS390RoundConditionCode(r2_val, INT32_MAX, INT32_MIN);
-
-      switch (mask_val) {
-        case CURRENT_ROUNDING_MODE:
-        case ROUND_TO_PREPARE_FOR_SHORTER_PRECISION: {
-          r1_val = static_cast<int32_t>(r2_val);
-          break;
-        }
-        case ROUND_TO_NEAREST_WITH_TIES_AWAY_FROM_0: {
-          double ceil_val = std::ceil(r2_val);
-          double floor_val = std::floor(r2_val);
-          double sub_val1 = std::fabs(r2_val - floor_val);
-          double sub_val2 = std::fabs(r2_val - ceil_val);
-          if (sub_val1 > sub_val2) {
-            r1_val = static_cast<int32_t>(ceil_val);
-          } else if (sub_val1 < sub_val2) {
-            r1_val = static_cast<int32_t>(floor_val);
-          } else {  // round away from zero:
-            if (r2_val > 0.0) {
-              r1_val = static_cast<int32_t>(ceil_val);
-            } else {
-              r1_val = static_cast<int32_t>(floor_val);
-            }
-          }
-          break;
-        }
-        case ROUND_TO_NEAREST_WITH_TIES_TO_EVEN: {
-          double ceil_val = std::ceil(r2_val);
-          double floor_val = std::floor(r2_val);
-          double sub_val1 = std::fabs(r2_val - floor_val);
-          double sub_val2 = std::fabs(r2_val - ceil_val);
-          if (sub_val1 > sub_val2) {
-            r1_val = static_cast<int32_t>(ceil_val);
-          } else if (sub_val1 < sub_val2) {
-            r1_val = static_cast<int32_t>(floor_val);
-          } else {  // check which one is even:
-            int32_t c_v = static_cast<int32_t>(ceil_val);
-            int32_t f_v = static_cast<int32_t>(floor_val);
-            if (f_v % 2 == 0)
-              r1_val = f_v;
-            else
-              r1_val = c_v;
-          }
-          break;
-        }
-        case ROUND_TOWARD_0: {
-          // check for overflow, cast r2_val to 64bit integer
-          // then check value within the range of INT_MIN and INT_MAX
-          // and set condition code accordingly
-          int64_t temp = static_cast<int64_t>(r2_val);
-          if (temp < INT_MIN || temp > INT_MAX) {
-            condition_reg_ = CC_OF;
-          }
-          r1_val = static_cast<int32_t>(r2_val);
-          break;
-        }
-        case ROUND_TOWARD_PLUS_INFINITE: {
-          r1_val = static_cast<int32_t>(std::ceil(r2_val));
-          break;
-        }
-        case ROUND_TOWARD_MINUS_INFINITE: {
-          // check for overflow, cast r2_val to 64bit integer
-          // then check value within the range of INT_MIN and INT_MAX
-          // and set condition code accordingly
-          int64_t temp = static_cast<int64_t>(std::floor(r2_val));
-          if (temp < INT_MIN || temp > INT_MAX) {
-            condition_reg_ = CC_OF;
-          }
-          r1_val = static_cast<int32_t>(std::floor(r2_val));
-          break;
-        }
-        default:
-          UNREACHABLE();
-      }
-      set_low_register(r1, r1_val);
-      break;
-    }
-    case CGDBR: {
-      int mask_val = rreInstr->M3Value();
-      int64_t r1_val = 0;
-
-      SetS390RoundConditionCode(r2_val, INT64_MAX, INT64_MIN);
-
-      switch (mask_val) {
-        case CURRENT_ROUNDING_MODE:
-        case ROUND_TO_NEAREST_WITH_TIES_AWAY_FROM_0:
-        case ROUND_TO_PREPARE_FOR_SHORTER_PRECISION: {
-          UNIMPLEMENTED();
-          break;
-        }
-        case ROUND_TO_NEAREST_WITH_TIES_TO_EVEN: {
-          double ceil_val = std::ceil(r2_val);
-          double floor_val = std::floor(r2_val);
-          if (std::abs(r2_val - floor_val) > std::abs(r2_val - ceil_val)) {
-            r1_val = static_cast<int64_t>(ceil_val);
-          } else if (std::abs(r2_val - floor_val) <
-                     std::abs(r2_val - ceil_val)) {
-            r1_val = static_cast<int64_t>(floor_val);
-          } else {  // check which one is even:
-            int64_t c_v = static_cast<int64_t>(ceil_val);
-            int64_t f_v = static_cast<int64_t>(floor_val);
-            if (f_v % 2 == 0)
-              r1_val = f_v;
-            else
-              r1_val = c_v;
-          }
-          break;
-        }
-        case ROUND_TOWARD_0: {
-          r1_val = static_cast<int64_t>(r2_val);
-          break;
-        }
-        case ROUND_TOWARD_PLUS_INFINITE: {
-          r1_val = static_cast<int64_t>(std::ceil(r2_val));
-          break;
-        }
-        case ROUND_TOWARD_MINUS_INFINITE: {
-          r1_val = static_cast<int64_t>(std::floor(r2_val));
-          break;
-        }
-        default:
-          UNREACHABLE();
-      }
-      set_register(r1, r1_val);
-      break;
-    }
-    case CGEBR: {
-      int mask_val = rreInstr->M3Value();
-      int64_t r1_val = 0;
-
-      SetS390RoundConditionCode(r2_fval, INT64_MAX, INT64_MIN);
-
-      switch (mask_val) {
-        case CURRENT_ROUNDING_MODE:
-        case ROUND_TO_NEAREST_WITH_TIES_AWAY_FROM_0:
-        case ROUND_TO_PREPARE_FOR_SHORTER_PRECISION: {
-          UNIMPLEMENTED();
-          break;
-        }
-        case ROUND_TO_NEAREST_WITH_TIES_TO_EVEN: {
-          float ceil_val = std::ceil(r2_fval);
-          float floor_val = std::floor(r2_fval);
-          if (std::abs(r2_fval - floor_val) > std::abs(r2_fval - ceil_val)) {
-            r1_val = static_cast<int64_t>(ceil_val);
-          } else if (std::abs(r2_fval - floor_val) <
-                     std::abs(r2_fval - ceil_val)) {
-            r1_val = static_cast<int64_t>(floor_val);
-          } else {  // check which one is even:
-            int64_t c_v = static_cast<int64_t>(ceil_val);
-            int64_t f_v = static_cast<int64_t>(floor_val);
-            if (f_v % 2 == 0)
-              r1_val = f_v;
-            else
-              r1_val = c_v;
-          }
-          break;
-        }
-        case ROUND_TOWARD_0: {
-          r1_val = static_cast<int64_t>(r2_fval);
-          break;
-        }
-        case ROUND_TOWARD_PLUS_INFINITE: {
-          r1_val = static_cast<int64_t>(std::ceil(r2_fval));
-          break;
-        }
-        case ROUND_TOWARD_MINUS_INFINITE: {
-          r1_val = static_cast<int64_t>(std::floor(r2_fval));
-          break;
-        }
-        default:
-          UNREACHABLE();
-      }
-      set_register(r1, r1_val);
-      break;
-    }
-    case CFEBR: {
-      int mask_val = rreInstr->M3Value();
-      int32_t r1_val = 0;
-
-      SetS390RoundConditionCode(r2_fval, INT32_MAX, INT32_MIN);
-
-      switch (mask_val) {
-        case CURRENT_ROUNDING_MODE:
-        case ROUND_TO_PREPARE_FOR_SHORTER_PRECISION: {
-          r1_val = static_cast<int32_t>(r2_fval);
-          break;
-        }
-        case ROUND_TO_NEAREST_WITH_TIES_AWAY_FROM_0: {
-          float ceil_val = std::ceil(r2_fval);
-          float floor_val = std::floor(r2_fval);
-          float sub_val1 = std::fabs(r2_fval - floor_val);
-          float sub_val2 = std::fabs(r2_fval - ceil_val);
-          if (sub_val1 > sub_val2) {
-            r1_val = static_cast<int32_t>(ceil_val);
-          } else if (sub_val1 < sub_val2) {
-            r1_val = static_cast<int32_t>(floor_val);
-          } else {  // round away from zero:
-            if (r2_fval > 0.0) {
-              r1_val = static_cast<int32_t>(ceil_val);
-            } else {
-              r1_val = static_cast<int32_t>(floor_val);
-            }
-          }
-          break;
-        }
-        case ROUND_TO_NEAREST_WITH_TIES_TO_EVEN: {
-          float ceil_val = std::ceil(r2_fval);
-          float floor_val = std::floor(r2_fval);
-          float sub_val1 = std::fabs(r2_fval - floor_val);
-          float sub_val2 = std::fabs(r2_fval - ceil_val);
-          if (sub_val1 > sub_val2) {
-            r1_val = static_cast<int32_t>(ceil_val);
-          } else if (sub_val1 < sub_val2) {
-            r1_val = static_cast<int32_t>(floor_val);
-          } else {  // check which one is even:
-            int32_t c_v = static_cast<int32_t>(ceil_val);
-            int32_t f_v = static_cast<int32_t>(floor_val);
-            if (f_v % 2 == 0)
-              r1_val = f_v;
-            else
-              r1_val = c_v;
-          }
-          break;
-        }
-        case ROUND_TOWARD_0: {
-          // check for overflow, cast r2_fval to 64bit integer
-          // then check value within the range of INT_MIN and INT_MAX
-          // and set condition code accordingly
-          int64_t temp = static_cast<int64_t>(r2_fval);
-          if (temp < INT_MIN || temp > INT_MAX) {
-            condition_reg_ = CC_OF;
-          }
-          r1_val = static_cast<int32_t>(r2_fval);
-          break;
-        }
-        case ROUND_TOWARD_PLUS_INFINITE: {
-          r1_val = static_cast<int32_t>(std::ceil(r2_fval));
-          break;
-        }
-        case ROUND_TOWARD_MINUS_INFINITE: {
-          // check for overflow, cast r2_fval to 64bit integer
-          // then check value within the range of INT_MIN and INT_MAX
-          // and set condition code accordingly
-          int64_t temp = static_cast<int64_t>(std::floor(r2_fval));
-          if (temp < INT_MIN || temp > INT_MAX) {
-            condition_reg_ = CC_OF;
-          }
-          r1_val = static_cast<int32_t>(std::floor(r2_fval));
-          break;
-        }
-        default:
-          UNREACHABLE();
-      }
-      set_low_register(r1, r1_val);
-
-      break;
-    }
-    default:
-      UNREACHABLE();
-  }
-}
-
-/**
- * Decodes and simulates four byte floating point instructions
- */
-bool Simulator::DecodeFourByteFloatingPoint(Instruction* instr) {
-  Opcode op = instr->S390OpcodeValue();
-
-  switch (op) {
-    case ADBR:
-    case AEBR:
-    case SDBR:
-    case SEBR:
-    case MDBR:
-    case MEEBR:
-    case MADBR:
-    case DDBR:
-    case DEBR:
-    case CDBR:
-    case CEBR:
-    case CDFBR:
-    case CDGBR:
-    case CEGBR:
-    case CGEBR:
-    case CFDBR:
-    case CGDBR:
-    case SQDBR:
-    case SQEBR:
-    case CFEBR:
-    case CEFBR:
-    case LCDBR:
-    case LCEBR:
-    case LPDBR:
-    case LPEBR: {
-      RREInstruction* rreInstr = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreInstr->R1Value();
-      int r2 = rreInstr->R2Value();
-      double r1_val = get_double_from_d_register(r1);
-      double r2_val = get_double_from_d_register(r2);
-      float fr1_val = get_float32_from_d_register(r1);
-      float fr2_val = get_float32_from_d_register(r2);
-      if (op == ADBR) {
-        r1_val += r2_val;
-        set_d_register_from_double(r1, r1_val);
-        SetS390ConditionCode<double>(r1_val, 0);
-      } else if (op == AEBR) {
-        fr1_val += fr2_val;
-        set_d_register_from_float32(r1, fr1_val);
-        SetS390ConditionCode<float>(fr1_val, 0);
-      } else if (op == SDBR) {
-        r1_val -= r2_val;
-        set_d_register_from_double(r1, r1_val);
-        SetS390ConditionCode<double>(r1_val, 0);
-      } else if (op == SEBR) {
-        fr1_val -= fr2_val;
-        set_d_register_from_float32(r1, fr1_val);
-        SetS390ConditionCode<float>(fr1_val, 0);
-      } else if (op == MDBR) {
-        r1_val *= r2_val;
-        set_d_register_from_double(r1, r1_val);
-        SetS390ConditionCode<double>(r1_val, 0);
-      } else if (op == MEEBR) {
-        fr1_val *= fr2_val;
-        set_d_register_from_float32(r1, fr1_val);
-        SetS390ConditionCode<float>(fr1_val, 0);
-      } else if (op == MADBR) {
-        RRDInstruction* rrdInstr = reinterpret_cast<RRDInstruction*>(instr);
-        int r1 = rrdInstr->R1Value();
-        int r2 = rrdInstr->R2Value();
-        int r3 = rrdInstr->R3Value();
-        double r1_val = get_double_from_d_register(r1);
-        double r2_val = get_double_from_d_register(r2);
-        double r3_val = get_double_from_d_register(r3);
-        r1_val += r2_val * r3_val;
-        set_d_register_from_double(r1, r1_val);
-        SetS390ConditionCode<double>(r1_val, 0);
-      } else if (op == DDBR) {
-        r1_val /= r2_val;
-        set_d_register_from_double(r1, r1_val);
-        SetS390ConditionCode<double>(r1_val, 0);
-      } else if (op == DEBR) {
-        fr1_val /= fr2_val;
-        set_d_register_from_float32(r1, fr1_val);
-        SetS390ConditionCode<float>(fr1_val, 0);
-      } else if (op == CDBR) {
-        if (isNaN(r1_val) || isNaN(r2_val)) {
-          condition_reg_ = CC_OF;
-        } else {
-          SetS390ConditionCode<double>(r1_val, r2_val);
-        }
-      } else if (op == CEBR) {
-        if (isNaN(fr1_val) || isNaN(fr2_val)) {
-          condition_reg_ = CC_OF;
-        } else {
-          SetS390ConditionCode<float>(fr1_val, fr2_val);
-        }
-      } else if (op == CDGBR) {
-        int64_t r2_val = get_register(r2);
-        double r1_val = static_cast<double>(r2_val);
-        set_d_register_from_double(r1, r1_val);
-      } else if (op == CEGBR) {
-        int64_t fr2_val = get_register(r2);
-        float fr1_val = static_cast<float>(fr2_val);
-        set_d_register_from_float32(r1, fr1_val);
-      } else if (op == CDFBR) {
-        int32_t r2_val = get_low_register<int32_t>(r2);
-        double r1_val = static_cast<double>(r2_val);
-        set_d_register_from_double(r1, r1_val);
-      } else if (op == CEFBR) {
-        int32_t fr2_val = get_low_register<int32_t>(r2);
-        float fr1_val = static_cast<float>(fr2_val);
-        set_d_register_from_float32(r1, fr1_val);
-      } else if (op == CFDBR) {
-        DecodeFourByteFloatingPointRound(instr);
-      } else if (op == CGDBR) {
-        DecodeFourByteFloatingPointRound(instr);
-      } else if (op == CGEBR) {
-        DecodeFourByteFloatingPointRound(instr);
-      } else if (op == SQDBR) {
-        r1_val = std::sqrt(r2_val);
-        set_d_register_from_double(r1, r1_val);
-      } else if (op == SQEBR) {
-        fr1_val = std::sqrt(fr2_val);
-        set_d_register_from_float32(r1, fr1_val);
-      } else if (op == CFEBR) {
-        DecodeFourByteFloatingPointRound(instr);
-      } else if (op == LCDBR) {
-        r1_val = -r2_val;
-        set_d_register_from_double(r1, r1_val);
-        if (r2_val != r2_val) {  // input is NaN
-          condition_reg_ = CC_OF;
-        } else if (r2_val == 0) {
-          condition_reg_ = CC_EQ;
-        } else if (r2_val < 0) {
-          condition_reg_ = CC_LT;
-        } else if (r2_val > 0) {
-          condition_reg_ = CC_GT;
-        }
-      } else if (op == LCEBR) {
-        fr1_val = -fr2_val;
-        set_d_register_from_float32(r1, fr1_val);
-        if (fr2_val != fr2_val) {  // input is NaN
-          condition_reg_ = CC_OF;
-        } else if (fr2_val == 0) {
-          condition_reg_ = CC_EQ;
-        } else if (fr2_val < 0) {
-          condition_reg_ = CC_LT;
-        } else if (fr2_val > 0) {
-          condition_reg_ = CC_GT;
-        }
-      } else if (op == LPDBR) {
-        r1_val = std::fabs(r2_val);
-        set_d_register_from_double(r1, r1_val);
-        if (r2_val != r2_val) {  // input is NaN
-          condition_reg_ = CC_OF;
-        } else if (r2_val == 0) {
-          condition_reg_ = CC_EQ;
-        } else {
-          condition_reg_ = CC_GT;
-        }
-      } else if (op == LPEBR) {
-        fr1_val = std::fabs(fr2_val);
-        set_d_register_from_float32(r1, fr1_val);
-        if (fr2_val != fr2_val) {  // input is NaN
-          condition_reg_ = CC_OF;
-        } else if (fr2_val == 0) {
-          condition_reg_ = CC_EQ;
-        } else {
-          condition_reg_ = CC_GT;
-        }
-      } else {
-        UNREACHABLE();
-      }
-      break;
-    }
-    case CDLFBR:
-    case CDLGBR:
-    case CELGBR:
-    case CLFDBR:
-    case CELFBR:
-    case CLGDBR:
-    case CLGEBR:
-    case CLFEBR: {
-      DecodeFourByteFloatingPointIntConversion(instr);
-      break;
-    }
-    case TMLL: {
-      RIInstruction* riinst = reinterpret_cast<RIInstruction*>(instr);
-      int r1 = riinst->R1Value();
-      int mask = riinst->I2Value() & 0x0000FFFF;
-      if (mask == 0) {
-        condition_reg_ = 0x0;
-        break;
-      }
-      uint32_t r1_val = get_low_register<uint32_t>(r1);
-      r1_val = r1_val & 0x0000FFFF;  // uses only the last 16bits
-
-      // Test if all selected bits are Zero
-      bool allSelectedBitsAreZeros = true;
-      for (int i = 0; i < 15; i++) {
-        if (mask & (1 << i)) {
-          if (r1_val & (1 << i)) {
-            allSelectedBitsAreZeros = false;
-            break;
-          }
-        }
-      }
-      if (allSelectedBitsAreZeros) {
-        condition_reg_ = 0x8;
-        break;  // Done!
-      }
-
-      // Test if all selected bits are one
-      bool allSelectedBitsAreOnes = true;
-      for (int i = 0; i < 15; i++) {
-        if (mask & (1 << i)) {
-          if (!(r1_val & (1 << i))) {
-            allSelectedBitsAreOnes = false;
-            break;
-          }
-        }
-      }
-      if (allSelectedBitsAreOnes) {
-        condition_reg_ = 0x1;
-        break;  // Done!
-      }
-
-      // Now we know selected bits mixed zeros and ones
-      // Test if the leftmost bit is zero or one
-      for (int i = 14; i >= 0; i--) {
-        if (mask & (1 << i)) {
-          if (r1_val & (1 << i)) {
-            // leftmost bit is one
-            condition_reg_ = 0x2;
-          } else {
-            // leftmost bit is zero
-            condition_reg_ = 0x4;
-          }
-          break;  // Done!
-        }
-      }
-      break;
-    }
-    case LEDBR: {
-      RREInstruction* rreInst = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreInst->R1Value();
-      int r2 = rreInst->R2Value();
-      double r2_val = get_double_from_d_register(r2);
-      set_d_register_from_float32(r1, static_cast<float>(r2_val));
-      break;
-    }
-    case FIDBRA: {
-      RRFInstruction* rrfInst = reinterpret_cast<RRFInstruction*>(instr);
-      int r1 = rrfInst->R1Value();
-      int r2 = rrfInst->R2Value();
-      int m3 = rrfInst->M3Value();
-      double r2_val = get_double_from_d_register(r2);
-      DCHECK(rrfInst->M4Value() == 0);
-      switch (m3) {
-        case Assembler::FIDBRA_ROUND_TO_NEAREST_AWAY_FROM_0:
-          set_d_register_from_double(r1, round(r2_val));
-          break;
-        case Assembler::FIDBRA_ROUND_TOWARD_0:
-          set_d_register_from_double(r1, trunc(r2_val));
-          break;
-        case Assembler::FIDBRA_ROUND_TOWARD_POS_INF:
-          set_d_register_from_double(r1, std::ceil(r2_val));
-          break;
-        case Assembler::FIDBRA_ROUND_TOWARD_NEG_INF:
-          set_d_register_from_double(r1, std::floor(r2_val));
-          break;
-        default:
-          UNIMPLEMENTED();
-          break;
-      }
-      break;
-    }
-    case FIEBRA: {
-      RRFInstruction* rrfInst = reinterpret_cast<RRFInstruction*>(instr);
-      int r1 = rrfInst->R1Value();
-      int r2 = rrfInst->R2Value();
-      int m3 = rrfInst->M3Value();
-      float r2_val = get_float32_from_d_register(r2);
-      DCHECK(rrfInst->M4Value() == 0);
-      switch (m3) {
-        case Assembler::FIDBRA_ROUND_TO_NEAREST_AWAY_FROM_0:
-          set_d_register_from_float32(r1, round(r2_val));
-          break;
-        case Assembler::FIDBRA_ROUND_TOWARD_0:
-          set_d_register_from_float32(r1, trunc(r2_val));
-          break;
-        case Assembler::FIDBRA_ROUND_TOWARD_POS_INF:
-          set_d_register_from_float32(r1, std::ceil(r2_val));
-          break;
-        case Assembler::FIDBRA_ROUND_TOWARD_NEG_INF:
-          set_d_register_from_float32(r1, std::floor(r2_val));
-          break;
-        default:
-          UNIMPLEMENTED();
-          break;
-      }
-      break;
-    }
-    case MSDBR: {
-      UNIMPLEMENTED();
-      break;
-    }
-    case LDEBR: {
-      RREInstruction* rreInstr = reinterpret_cast<RREInstruction*>(instr);
-      int r1 = rreInstr->R1Value();
-      int r2 = rreInstr->R2Value();
-      float fp_val = get_float32_from_d_register(r2);
-      double db_val = static_cast<double>(fp_val);
-      set_d_register_from_double(r1, db_val);
-      break;
-    }
-    default: {
-      UNREACHABLE();
-      return false;
-    }
-  }
-  return true;
-}
-
-// Decode routine for six-byte instructions
-bool Simulator::DecodeSixByte(Instruction* instr) {
-  Opcode op = instr->S390OpcodeValue();
-
-  // Pre-cast instruction to various types
-  RIEInstruction* rieInstr = reinterpret_cast<RIEInstruction*>(instr);
-  RILInstruction* rilInstr = reinterpret_cast<RILInstruction*>(instr);
-  RSYInstruction* rsyInstr = reinterpret_cast<RSYInstruction*>(instr);
-  RXEInstruction* rxeInstr = reinterpret_cast<RXEInstruction*>(instr);
-  RXYInstruction* rxyInstr = reinterpret_cast<RXYInstruction*>(instr);
-  SIYInstruction* siyInstr = reinterpret_cast<SIYInstruction*>(instr);
-  SILInstruction* silInstr = reinterpret_cast<SILInstruction*>(instr);
-  SSInstruction* ssInstr = reinterpret_cast<SSInstruction*>(instr);
-
-  switch (op) {
-    case CLIY: {
-      // Compare Immediate (Mem - Imm) (8)
-      int b1 = siyInstr->B1Value();
-      int64_t b1_val = (b1 == 0) ? 0 : get_register(b1);
-      intptr_t d1_val = siyInstr->D1Value();
-      intptr_t addr = b1_val + d1_val;
-      uint8_t mem_val = ReadB(addr);
-      uint8_t imm_val = siyInstr->I2Value();
-      SetS390ConditionCode<uint8_t>(mem_val, imm_val);
-      break;
-    }
-    case TMY: {
-      // Test Under Mask (Mem - Imm) (8)
-      int b1 = siyInstr->B1Value();
-      int64_t b1_val = (b1 == 0) ? 0 : get_register(b1);
-      intptr_t d1_val = siyInstr->D1Value();
-      intptr_t addr = b1_val + d1_val;
-      uint8_t mem_val = ReadB(addr);
-      uint8_t imm_val = siyInstr->I2Value();
-      uint8_t selected_bits = mem_val & imm_val;
-      // CC0: Selected bits are zero
-      // CC1: Selected bits mixed zeros and ones
-      // CC3: Selected bits all ones
-      if (0 == selected_bits) {
-        condition_reg_ = CC_EQ;  // CC0
-      } else if (selected_bits == imm_val) {
-        condition_reg_ = 0x1;  // CC3
-      } else {
-        condition_reg_ = 0x4;  // CC1
-      }
-      break;
-    }
-    case LDEB: {
-      // Load Float
-      int r1 = rxeInstr->R1Value();
-      int rb = rxeInstr->B2Value();
-      int rx = rxeInstr->X2Value();
-      int offset = rxeInstr->D2Value();
-      int64_t rb_val = (rb == 0) ? 0 : get_register(rb);
-      int64_t rx_val = (rx == 0) ? 0 : get_register(rx);
-      double ret = static_cast<double>(
-          *reinterpret_cast<float*>(rx_val + rb_val + offset));
-      set_d_register_from_double(r1, ret);
-      break;
-    }
-    case LAY: {
-      // Load Address
-      int r1 = rxyInstr->R1Value();
-      int rb = rxyInstr->B2Value();
-      int rx = rxyInstr->X2Value();
-      int offset = rxyInstr->D2Value();
-      int64_t rb_val = (rb == 0) ? 0 : get_register(rb);
-      int64_t rx_val = (rx == 0) ? 0 : get_register(rx);
-      set_register(r1, rx_val + rb_val + offset);
-      break;
-    }
-    case LARL: {
-      // Load Addresss Relative Long
-      int r1 = rilInstr->R1Value();
-      intptr_t offset = rilInstr->I2Value() * 2;
-      set_register(r1, get_pc() + offset);
-      break;
-    }
-    case LLILF: {
-      // Load Logical into lower 32-bits (zero extend upper 32-bits)
-      int r1 = rilInstr->R1Value();
-      uint64_t imm = static_cast<uint64_t>(rilInstr->I2UnsignedValue());
-      set_register(r1, imm);
-      break;
-    }
-    case LLIHF: {
-      // Load Logical Immediate into high word
-      int r1 = rilInstr->R1Value();
-      uint64_t imm = static_cast<uint64_t>(rilInstr->I2UnsignedValue());
-      set_register(r1, imm << 32);
-      break;
-    }
-    case OILF:
-    case NILF:
-    case IILF: {
-      // Bitwise Op on lower 32-bits
-      int r1 = rilInstr->R1Value();
-      uint32_t imm = rilInstr->I2UnsignedValue();
-      uint32_t alu_out = get_low_register<uint32_t>(r1);
-      if (NILF == op) {
-        alu_out &= imm;
-        SetS390BitWiseConditionCode<uint32_t>(alu_out);
-      } else if (OILF == op) {
-        alu_out |= imm;
-        SetS390BitWiseConditionCode<uint32_t>(alu_out);
-      } else if (op == IILF) {
-        alu_out = imm;
-      } else {
-        DCHECK(false);
-      }
-      set_low_register(r1, alu_out);
-      break;
-    }
-    case OIHF:
-    case NIHF:
-    case IIHF: {
-      // Bitwise Op on upper 32-bits
-      int r1 = rilInstr->R1Value();
-      uint32_t imm = rilInstr->I2Value();
-      uint32_t alu_out = get_high_register<uint32_t>(r1);
-      if (op == NIHF) {
-        alu_out &= imm;
-        SetS390BitWiseConditionCode<uint32_t>(alu_out);
-      } else if (op == OIHF) {
-        alu_out |= imm;
-        SetS390BitWiseConditionCode<uint32_t>(alu_out);
-      } else if (op == IIHF) {
-        alu_out = imm;
-      } else {
-        DCHECK(false);
-      }
-      set_high_register(r1, alu_out);
-      break;
-    }
-    case CLFI: {
-      // Compare Logical with Immediate (32)
-      int r1 = rilInstr->R1Value();
-      uint32_t imm = rilInstr->I2UnsignedValue();
-      SetS390ConditionCode<uint32_t>(get_low_register<uint32_t>(r1), imm);
-      break;
-    }
-    case CFI: {
-      // Compare with Immediate (32)
-      int r1 = rilInstr->R1Value();
-      int32_t imm = rilInstr->I2Value();
-      SetS390ConditionCode<int32_t>(get_low_register<int32_t>(r1), imm);
-      break;
-    }
-    case CLGFI: {
-      // Compare Logical with Immediate (64)
-      int r1 = rilInstr->R1Value();
-      uint64_t imm = static_cast<uint64_t>(rilInstr->I2UnsignedValue());
-      SetS390ConditionCode<uint64_t>(get_register(r1), imm);
-      break;
-    }
-    case CGFI: {
-      // Compare with Immediate (64)
-      int r1 = rilInstr->R1Value();
-      int64_t imm = static_cast<int64_t>(rilInstr->I2Value());
-      SetS390ConditionCode<int64_t>(get_register(r1), imm);
-      break;
-    }
-    case BRASL: {
-      // Branch and Save Relative Long
-      int r1 = rilInstr->R1Value();
-      intptr_t d2 = rilInstr->I2Value();
-      intptr_t pc = get_pc();
-      set_register(r1, pc + 6);  // save next instruction to register
-      set_pc(pc + d2 * 2);       // update register
-      break;
-    }
-    case BRCL: {
-      // Branch on Condition Relative Long
-      Condition m1 = (Condition)rilInstr->R1Value();
-      if (TestConditionCode((Condition)m1)) {
-        intptr_t offset = rilInstr->I2Value() * 2;
-        set_pc(get_pc() + offset);
-      }
-      break;
-    }
-    case LMG:
-    case STMG: {
-      // Store Multiple 64-bits.
-      int r1 = rsyInstr->R1Value();
-      int r3 = rsyInstr->R3Value();
-      int rb = rsyInstr->B2Value();
-      int offset = rsyInstr->D2Value();
-
-      // Regs roll around if r3 is less than r1.
-      // Artifically increase r3 by 16 so we can calculate
-      // the number of regs stored properly.
-      if (r3 < r1) r3 += 16;
-
-      int64_t rb_val = (rb == 0) ? 0 : get_register(rb);
-
-      // Store each register in ascending order.
-      for (int i = 0; i <= r3 - r1; i++) {
-        if (op == LMG) {
-          int64_t value = ReadDW(rb_val + offset + 8 * i);
-          set_register((r1 + i) % 16, value);
-        } else if (op == STMG) {
-          int64_t value = get_register((r1 + i) % 16);
-          WriteDW(rb_val + offset + 8 * i, value);
-        } else {
-          DCHECK(false);
-        }
-      }
-      break;
-    }
-    case SLLK:
-    case RLL:
-    case SRLK:
-    case SLLG:
-    case RLLG:
-    case SRLG: {
-      DecodeSixByteBitShift(instr);
-      break;
-    }
-    case SLAK:
-    case SRAK: {
-      // 32-bit non-clobbering shift-left/right arithmetic
-      int r1 = rsyInstr->R1Value();
-      int r3 = rsyInstr->R3Value();
-      int b2 = rsyInstr->B2Value();
-      intptr_t d2 = rsyInstr->D2Value();
-      // only takes rightmost 6 bits
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int shiftBits = (b2_val + d2) & 0x3F;
-      int32_t r3_val = get_low_register<int32_t>(r3);
-      int32_t alu_out = 0;
-      bool isOF = false;
-      if (op == SLAK) {
-        isOF = CheckOverflowForShiftLeft(r3_val, shiftBits);
-        alu_out = r3_val << shiftBits;
-      } else if (op == SRAK) {
-        alu_out = r3_val >> shiftBits;
-      }
-      set_low_register(r1, alu_out);
-      SetS390ConditionCode<int32_t>(alu_out, 0);
-      SetS390OverflowCode(isOF);
-      break;
-    }
-    case SLAG:
-    case SRAG: {
-      // 64-bit non-clobbering shift-left/right arithmetic
-      int r1 = rsyInstr->R1Value();
-      int r3 = rsyInstr->R3Value();
-      int b2 = rsyInstr->B2Value();
-      intptr_t d2 = rsyInstr->D2Value();
-      // only takes rightmost 6 bits
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int shiftBits = (b2_val + d2) & 0x3F;
-      int64_t r3_val = get_register(r3);
-      intptr_t alu_out = 0;
-      bool isOF = false;
-      if (op == SLAG) {
-        isOF = CheckOverflowForShiftLeft(r3_val, shiftBits);
-        alu_out = r3_val << shiftBits;
-      } else if (op == SRAG) {
-        alu_out = r3_val >> shiftBits;
-      }
-      set_register(r1, alu_out);
-      SetS390ConditionCode<intptr_t>(alu_out, 0);
-      SetS390OverflowCode(isOF);
-      break;
-    }
-    case LMY:
-    case STMY: {
-      RSYInstruction* rsyInstr = reinterpret_cast<RSYInstruction*>(instr);
-      // Load/Store Multiple (32)
-      int r1 = rsyInstr->R1Value();
-      int r3 = rsyInstr->R3Value();
-      int b2 = rsyInstr->B2Value();
-      int offset = rsyInstr->D2Value();
-
-      // Regs roll around if r3 is less than r1.
-      // Artifically increase r3 by 16 so we can calculate
-      // the number of regs stored properly.
-      if (r3 < r1) r3 += 16;
-
-      int32_t b2_val = (b2 == 0) ? 0 : get_low_register<int32_t>(b2);
-
-      // Store each register in ascending order.
-      for (int i = 0; i <= r3 - r1; i++) {
-        if (op == LMY) {
-          int32_t value = ReadW(b2_val + offset + 4 * i, instr);
-          set_low_register((r1 + i) % 16, value);
-        } else {
-          int32_t value = get_low_register<int32_t>((r1 + i) % 16);
-          WriteW(b2_val + offset + 4 * i, value, instr);
-        }
-      }
-      break;
-    }
-    case LT:
-    case LTG: {
-      // Load and Test (32/64)
-      int r1 = rxyInstr->R1Value();
-      int x2 = rxyInstr->X2Value();
-      int b2 = rxyInstr->B2Value();
-      int d2 = rxyInstr->D2Value();
-
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      intptr_t addr = x2_val + b2_val + d2;
-
-      if (op == LT) {
-        int32_t value = ReadW(addr, instr);
-        set_low_register(r1, value);
-        SetS390ConditionCode<int32_t>(value, 0);
-      } else if (op == LTG) {
-        int64_t value = ReadDW(addr);
-        set_register(r1, value);
-        SetS390ConditionCode<int64_t>(value, 0);
-      }
-      break;
-    }
-    case LY:
-    case LB:
-    case LGB:
-    case LG:
-    case LGF:
-    case LGH:
-    case LLGF:
-    case STG:
-    case STY:
-    case STCY:
-    case STHY:
-    case STEY:
-    case LDY:
-    case LHY:
-    case STDY:
-    case LEY: {
-      // Miscellaneous Loads and Stores
-      int r1 = rxyInstr->R1Value();
-      int x2 = rxyInstr->X2Value();
-      int b2 = rxyInstr->B2Value();
-      int d2 = rxyInstr->D2Value();
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      intptr_t addr = x2_val + b2_val + d2;
-      if (op == LY) {
-        uint32_t mem_val = ReadWU(addr, instr);
-        set_low_register(r1, mem_val);
-      } else if (op == LB) {
-        int32_t mem_val = ReadB(addr);
-        set_low_register(r1, mem_val);
-      } else if (op == LGB) {
-        int64_t mem_val = ReadB(addr);
-        set_register(r1, mem_val);
-      } else if (op == LG) {
-        int64_t mem_val = ReadDW(addr);
-        set_register(r1, mem_val);
-      } else if (op == LGF) {
-        int64_t mem_val = static_cast<int64_t>(ReadW(addr, instr));
-        set_register(r1, mem_val);
-      } else if (op == LGH) {
-        int64_t mem_val = static_cast<int64_t>(ReadH(addr, instr));
-        set_register(r1, mem_val);
-      } else if (op == LLGF) {
-        //      int r1 = rreInst->R1Value();
-        //      int r2 = rreInst->R2Value();
-        //      int32_t r2_val = get_low_register<int32_t>(r2);
-        //      uint64_t r2_finalval = (static_cast<uint64_t>(r2_val)
-        //        & 0x00000000ffffffff);
-        //      set_register(r1, r2_finalval);
-        //      break;
-        uint64_t mem_val = static_cast<uint64_t>(ReadWU(addr, instr));
-        set_register(r1, mem_val);
-      } else if (op == LDY) {
-        uint64_t dbl_val = *reinterpret_cast<uint64_t*>(addr);
-        set_d_register(r1, dbl_val);
-      } else if (op == STEY) {
-        int64_t frs_val = get_d_register(r1) >> 32;
-        WriteW(addr, static_cast<int32_t>(frs_val), instr);
-      } else if (op == LEY) {
-        float float_val = *reinterpret_cast<float*>(addr);
-        set_d_register_from_float32(r1, float_val);
-      } else if (op == STY) {
-        uint32_t value = get_low_register<uint32_t>(r1);
-        WriteW(addr, value, instr);
-      } else if (op == STG) {
-        uint64_t value = get_register(r1);
-        WriteDW(addr, value);
-      } else if (op == STDY) {
-        int64_t frs_val = get_d_register(r1);
-        WriteDW(addr, frs_val);
-      } else if (op == STCY) {
-        uint8_t value = get_low_register<uint32_t>(r1);
-        WriteB(addr, value);
-      } else if (op == STHY) {
-        uint16_t value = get_low_register<uint32_t>(r1);
-        WriteH(addr, value, instr);
-      } else if (op == LHY) {
-        int32_t result = static_cast<int32_t>(ReadH(addr, instr));
-        set_low_register(r1, result);
-      }
-      break;
-    }
-    case MVC: {
-      // Move Character
-      int b1 = ssInstr->B1Value();
-      intptr_t d1 = ssInstr->D1Value();
-      int b2 = ssInstr->B2Value();
-      intptr_t d2 = ssInstr->D2Value();
-      int length = ssInstr->Length();
-      int64_t b1_val = (b1 == 0) ? 0 : get_register(b1);
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      intptr_t src_addr = b2_val + d2;
-      intptr_t dst_addr = b1_val + d1;
-      // remember that the length is the actual length - 1
-      for (int i = 0; i < length + 1; ++i) {
-        WriteB(dst_addr++, ReadB(src_addr++));
-      }
-      break;
-    }
-    case MVHI: {
-      // Move Integer (32)
-      int b1 = silInstr->B1Value();
-      intptr_t d1 = silInstr->D1Value();
-      int16_t i2 = silInstr->I2Value();
-      int64_t b1_val = (b1 == 0) ? 0 : get_register(b1);
-      intptr_t src_addr = b1_val + d1;
-      WriteW(src_addr, i2, instr);
-      break;
-    }
-    case MVGHI: {
-      // Move Integer (64)
-      int b1 = silInstr->B1Value();
-      intptr_t d1 = silInstr->D1Value();
-      int16_t i2 = silInstr->I2Value();
-      int64_t b1_val = (b1 == 0) ? 0 : get_register(b1);
-      intptr_t src_addr = b1_val + d1;
-      WriteDW(src_addr, i2);
-      break;
-    }
-    case LLH:
-    case LLGH: {
-      // Load Logical Halfworld
-      int r1 = rxyInstr->R1Value();
-      int b2 = rxyInstr->B2Value();
-      int x2 = rxyInstr->X2Value();
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxyInstr->D2Value();
-      uint16_t mem_val = ReadHU(b2_val + d2_val + x2_val, instr);
-      if (op == LLH) {
-        set_low_register(r1, mem_val);
-      } else if (op == LLGH) {
-        set_register(r1, mem_val);
-      } else {
-        UNREACHABLE();
-      }
-      break;
-    }
-    case LLC:
-    case LLGC: {
-      // Load Logical Character - loads a byte and zero extends.
-      int r1 = rxyInstr->R1Value();
-      int b2 = rxyInstr->B2Value();
-      int x2 = rxyInstr->X2Value();
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxyInstr->D2Value();
-      uint8_t mem_val = ReadBU(b2_val + d2_val + x2_val);
-      if (op == LLC) {
-        set_low_register(r1, static_cast<uint32_t>(mem_val));
-      } else if (op == LLGC) {
-        set_register(r1, static_cast<uint64_t>(mem_val));
-      } else {
-        UNREACHABLE();
-      }
-      break;
-    }
-    case XIHF:
-    case XILF: {
-      int r1 = rilInstr->R1Value();
-      uint32_t imm = rilInstr->I2UnsignedValue();
-      uint32_t alu_out = 0;
-      if (op == XILF) {
-        alu_out = get_low_register<uint32_t>(r1);
-        alu_out = alu_out ^ imm;
-        set_low_register(r1, alu_out);
-      } else if (op == XIHF) {
-        alu_out = get_high_register<uint32_t>(r1);
-        alu_out = alu_out ^ imm;
-        set_high_register(r1, alu_out);
-      } else {
-        UNREACHABLE();
-      }
-      SetS390BitWiseConditionCode<uint32_t>(alu_out);
-      break;
-    }
-    case RISBG: {
-      // Rotate then insert selected bits
-      int r1 = rieInstr->R1Value();
-      int r2 = rieInstr->R2Value();
-      // Starting Bit Position is Bits 2-7 of I3 field
-      uint32_t start_bit = rieInstr->I3Value() & 0x3F;
-      // Ending Bit Position is Bits 2-7 of I4 field
-      uint32_t end_bit = rieInstr->I4Value() & 0x3F;
-      // Shift Amount is Bits 2-7 of I5 field
-      uint32_t shift_amount = rieInstr->I5Value() & 0x3F;
-      // Zero out Remaining (unslected) bits if Bit 0 of I4 is 1.
-      bool zero_remaining = (0 != (rieInstr->I4Value() & 0x80));
-
-      uint64_t src_val = get_register(r2);
-
-      // Rotate Left by Shift Amount first
-      uint64_t rotated_val =
-          (src_val << shift_amount) | (src_val >> (64 - shift_amount));
-      int32_t width = end_bit - start_bit + 1;
-
-      uint64_t selection_mask = 0;
-      if (width < 64) {
-        selection_mask = (static_cast<uint64_t>(1) << width) - 1;
-      } else {
-        selection_mask = static_cast<uint64_t>(static_cast<int64_t>(-1));
-      }
-      selection_mask = selection_mask << (63 - end_bit);
-
-      uint64_t selected_val = rotated_val & selection_mask;
-
-      if (!zero_remaining) {
-        // Merged the unselected bits from the original value
-        selected_val = (src_val & ~selection_mask) | selected_val;
-      }
-
-      // Condition code is set by treating result as 64-bit signed int
-      SetS390ConditionCode<int64_t>(selected_val, 0);
-      set_register(r1, selected_val);
-      break;
-    }
-    default:
-      return DecodeSixByteArithmetic(instr);
-  }
-  return true;
-}
-
-void Simulator::DecodeSixByteBitShift(Instruction* instr) {
-  Opcode op = instr->S390OpcodeValue();
-
-  // Pre-cast instruction to various types
-
-  RSYInstruction* rsyInstr = reinterpret_cast<RSYInstruction*>(instr);
-
-  switch (op) {
-    case SLLK:
-    case RLL:
-    case SRLK: {
-      // For SLLK/SRLL, the 32-bit third operand is shifted the number
-      // of bits specified by the second-operand address, and the result is
-      // placed at the first-operand location. Except for when the R1 and R3
-      // fields designate the same register, the third operand remains
-      // unchanged in general register R3.
-      int r1 = rsyInstr->R1Value();
-      int r3 = rsyInstr->R3Value();
-      int b2 = rsyInstr->B2Value();
-      intptr_t d2 = rsyInstr->D2Value();
-      // only takes rightmost 6 bits
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int shiftBits = (b2_val + d2) & 0x3F;
-      // unsigned
-      uint32_t r3_val = get_low_register<uint32_t>(r3);
-      uint32_t alu_out = 0;
-      if (SLLK == op) {
-        alu_out = r3_val << shiftBits;
-      } else if (SRLK == op) {
-        alu_out = r3_val >> shiftBits;
-      } else if (RLL == op) {
-        uint32_t rotateBits = r3_val >> (32 - shiftBits);
-        alu_out = (r3_val << shiftBits) | (rotateBits);
-      } else {
-        UNREACHABLE();
-      }
-      set_low_register(r1, alu_out);
-      break;
-    }
-    case SLLG:
-    case RLLG:
-    case SRLG: {
-      // For SLLG/SRLG, the 64-bit third operand is shifted the number
-      // of bits specified by the second-operand address, and the result is
-      // placed at the first-operand location. Except for when the R1 and R3
-      // fields designate the same register, the third operand remains
-      // unchanged in general register R3.
-      int r1 = rsyInstr->R1Value();
-      int r3 = rsyInstr->R3Value();
-      int b2 = rsyInstr->B2Value();
-      intptr_t d2 = rsyInstr->D2Value();
-      // only takes rightmost 6 bits
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int shiftBits = (b2_val + d2) & 0x3F;
-      // unsigned
-      uint64_t r3_val = get_register(r3);
-      uint64_t alu_out = 0;
-      if (op == SLLG) {
-        alu_out = r3_val << shiftBits;
-      } else if (op == SRLG) {
-        alu_out = r3_val >> shiftBits;
-      } else if (op == RLLG) {
-        uint64_t rotateBits = r3_val >> (64 - shiftBits);
-        alu_out = (r3_val << shiftBits) | (rotateBits);
-      } else {
-        UNREACHABLE();
-      }
-      set_register(r1, alu_out);
-      break;
-    }
-    default:
-      UNREACHABLE();
-  }
-}
-
-/**
- * Decodes and simulates six byte arithmetic instructions
- */
-bool Simulator::DecodeSixByteArithmetic(Instruction* instr) {
-  Opcode op = instr->S390OpcodeValue();
-
-  // Pre-cast instruction to various types
-  SIYInstruction* siyInstr = reinterpret_cast<SIYInstruction*>(instr);
-
-  switch (op) {
-    case CDB:
-    case ADB:
-    case SDB:
-    case MDB:
-    case DDB:
-    case SQDB: {
-      RXEInstruction* rxeInstr = reinterpret_cast<RXEInstruction*>(instr);
-      int b2 = rxeInstr->B2Value();
-      int x2 = rxeInstr->X2Value();
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxeInstr->D2Value();
-      double r1_val = get_double_from_d_register(rxeInstr->R1Value());
-      double dbl_val = ReadDouble(b2_val + x2_val + d2_val);
-
-      switch (op) {
-        case CDB:
-          SetS390ConditionCode<double>(r1_val, dbl_val);
-          break;
-        case ADB:
-          r1_val += dbl_val;
-          set_d_register_from_double(r1, r1_val);
-          SetS390ConditionCode<double>(r1_val, 0);
-          break;
-        case SDB:
-          r1_val -= dbl_val;
-          set_d_register_from_double(r1, r1_val);
-          SetS390ConditionCode<double>(r1_val, 0);
-          break;
-        case MDB:
-          r1_val *= dbl_val;
-          set_d_register_from_double(r1, r1_val);
-          SetS390ConditionCode<double>(r1_val, 0);
-          break;
-        case DDB:
-          r1_val /= dbl_val;
-          set_d_register_from_double(r1, r1_val);
-          SetS390ConditionCode<double>(r1_val, 0);
-          break;
-        case SQDB:
-          r1_val = std::sqrt(dbl_val);
-          set_d_register_from_double(r1, r1_val);
-        default:
-          UNREACHABLE();
-          break;
-      }
-      break;
-    }
-    case LRV:
-    case LRVH:
-    case STRV:
-    case STRVH: {
-      RXYInstruction* rxyInstr = reinterpret_cast<RXYInstruction*>(instr);
-      int r1 = rxyInstr->R1Value();
-      int x2 = rxyInstr->X2Value();
-      int b2 = rxyInstr->B2Value();
-      int d2 = rxyInstr->D2Value();
-      int32_t r1_val = get_low_register<int32_t>(r1);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      intptr_t mem_addr = b2_val + x2_val + d2;
-
-      if (op == LRVH) {
-        int16_t mem_val = ReadH(mem_addr, instr);
-        int32_t result = ByteReverse(mem_val) & 0x0000ffff;
-        result |= r1_val & 0xffff0000;
-        set_low_register(r1, result);
-      } else if (op == LRV) {
-        int32_t mem_val = ReadW(mem_addr, instr);
-        set_low_register(r1, ByteReverse(mem_val));
-      } else if (op == STRVH) {
-        int16_t result = static_cast<int16_t>(r1_val >> 16);
-        WriteH(mem_addr, ByteReverse(result), instr);
-      } else if (op == STRV) {
-        WriteW(mem_addr, ByteReverse(r1_val), instr);
-      }
-
-      break;
-    }
-    case AHIK:
-    case AGHIK: {
-      // Non-clobbering Add Halfword Immediate
-      RIEInstruction* rieInst = reinterpret_cast<RIEInstruction*>(instr);
-      int r1 = rieInst->R1Value();
-      int r2 = rieInst->R2Value();
-      bool isOF = false;
-      if (AHIK == op) {
-        // 32-bit Add
-        int32_t r2_val = get_low_register<int32_t>(r2);
-        int32_t imm = rieInst->I6Value();
-        isOF = CheckOverflowForIntAdd(r2_val, imm, int32_t);
-        set_low_register(r1, r2_val + imm);
-        SetS390ConditionCode<int32_t>(r2_val + imm, 0);
-      } else if (AGHIK == op) {
-        // 64-bit Add
-        int64_t r2_val = get_register(r2);
-        int64_t imm = static_cast<int64_t>(rieInst->I6Value());
-        isOF = CheckOverflowForIntAdd(r2_val, imm, int64_t);
-        set_register(r1, r2_val + imm);
-        SetS390ConditionCode<int64_t>(r2_val + imm, 0);
-      }
-      SetS390OverflowCode(isOF);
-      break;
-    }
-    case ALFI:
-    case SLFI: {
-      RILInstruction* rilInstr = reinterpret_cast<RILInstruction*>(instr);
-      int r1 = rilInstr->R1Value();
-      uint32_t imm = rilInstr->I2UnsignedValue();
-      uint32_t alu_out = get_low_register<uint32_t>(r1);
-      if (op == ALFI) {
-        alu_out += imm;
-      } else if (op == SLFI) {
-        alu_out -= imm;
-      }
-      SetS390ConditionCode<uint32_t>(alu_out, 0);
-      set_low_register(r1, alu_out);
-      break;
-    }
-    case ML: {
-      UNIMPLEMENTED();
-      break;
-    }
-    case AY:
-    case SY:
-    case NY:
-    case OY:
-    case XY:
-    case CY: {
-      RXYInstruction* rxyInstr = reinterpret_cast<RXYInstruction*>(instr);
-      int r1 = rxyInstr->R1Value();
-      int x2 = rxyInstr->X2Value();
-      int b2 = rxyInstr->B2Value();
-      int d2 = rxyInstr->D2Value();
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int32_t alu_out = get_low_register<int32_t>(r1);
-      int32_t mem_val = ReadW(b2_val + x2_val + d2, instr);
-      bool isOF = false;
-      if (op == AY) {
-        isOF = CheckOverflowForIntAdd(alu_out, mem_val, int32_t);
-        alu_out += mem_val;
-        SetS390ConditionCode<int32_t>(alu_out, 0);
-        SetS390OverflowCode(isOF);
-      } else if (op == SY) {
-        isOF = CheckOverflowForIntSub(alu_out, mem_val, int32_t);
-        alu_out -= mem_val;
-        SetS390ConditionCode<int32_t>(alu_out, 0);
-        SetS390OverflowCode(isOF);
-      } else if (op == NY) {
-        alu_out &= mem_val;
-        SetS390BitWiseConditionCode<uint32_t>(alu_out);
-      } else if (op == OY) {
-        alu_out |= mem_val;
-        SetS390BitWiseConditionCode<uint32_t>(alu_out);
-      } else if (op == XY) {
-        alu_out ^= mem_val;
-        SetS390BitWiseConditionCode<uint32_t>(alu_out);
-      } else if (op == CY) {
-        SetS390ConditionCode<int32_t>(alu_out, mem_val);
-      }
-      if (op != CY) {
-        set_low_register(r1, alu_out);
-      }
-      break;
-    }
-    case AHY:
-    case SHY: {
-      RXYInstruction* rxyInstr = reinterpret_cast<RXYInstruction*>(instr);
-      int32_t r1_val = get_low_register<int32_t>(rxyInstr->R1Value());
-      int b2 = rxyInstr->B2Value();
-      int x2 = rxyInstr->X2Value();
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxyInstr->D2Value();
-      int32_t mem_val =
-          static_cast<int32_t>(ReadH(b2_val + d2_val + x2_val, instr));
-      int32_t alu_out = 0;
-      bool isOF = false;
-      switch (op) {
-        case AHY:
-          alu_out = r1_val + mem_val;
-          isOF = CheckOverflowForIntAdd(r1_val, mem_val, int32_t);
-          break;
-        case SHY:
-          alu_out = r1_val - mem_val;
-          isOF = CheckOverflowForIntSub(r1_val, mem_val, int64_t);
-          break;
-        default:
-          UNREACHABLE();
-          break;
-      }
-      set_low_register(r1, alu_out);
-      SetS390ConditionCode<int32_t>(alu_out, 0);
-      SetS390OverflowCode(isOF);
-      break;
-    }
-    case AG:
-    case SG:
-    case NG:
-    case OG:
-    case XG:
-    case CG:
-    case CLG: {
-      RXYInstruction* rxyInstr = reinterpret_cast<RXYInstruction*>(instr);
-      int r1 = rxyInstr->R1Value();
-      int x2 = rxyInstr->X2Value();
-      int b2 = rxyInstr->B2Value();
-      int d2 = rxyInstr->D2Value();
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t alu_out = get_register(r1);
-      int64_t mem_val = ReadDW(b2_val + x2_val + d2);
-
-      switch (op) {
-        case AG: {
-          alu_out += mem_val;
-          SetS390ConditionCode<int32_t>(alu_out, 0);
-          break;
-        }
-        case SG: {
-          alu_out -= mem_val;
-          SetS390ConditionCode<int32_t>(alu_out, 0);
-          break;
-        }
-        case NG: {
-          alu_out &= mem_val;
-          SetS390BitWiseConditionCode<uint32_t>(alu_out);
-          break;
-        }
-        case OG: {
-          alu_out |= mem_val;
-          SetS390BitWiseConditionCode<uint32_t>(alu_out);
-          break;
-        }
-        case XG: {
-          alu_out ^= mem_val;
-          SetS390BitWiseConditionCode<uint32_t>(alu_out);
-          break;
-        }
-        case CG: {
-          SetS390ConditionCode<int64_t>(alu_out, mem_val);
-          break;
-        }
-        case CLG: {
-          SetS390ConditionCode<uint64_t>(alu_out, mem_val);
-          break;
-        }
-        default: {
-          DCHECK(false);
-          break;
-        }
-      }
-
-      if (op != CG) {
-        set_register(r1, alu_out);
-      }
-      break;
-    }
-    case ALY:
-    case SLY:
-    case CLY: {
-      RXYInstruction* rxyInstr = reinterpret_cast<RXYInstruction*>(instr);
-      int r1 = rxyInstr->R1Value();
-      int x2 = rxyInstr->X2Value();
-      int b2 = rxyInstr->B2Value();
-      int d2 = rxyInstr->D2Value();
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      uint32_t alu_out = get_low_register<uint32_t>(r1);
-      uint32_t mem_val = ReadWU(b2_val + x2_val + d2, instr);
-
-      if (op == ALY) {
-        alu_out += mem_val;
-        set_low_register(r1, alu_out);
-        SetS390ConditionCode<uint32_t>(alu_out, 0);
-      } else if (op == SLY) {
-        alu_out -= mem_val;
-        set_low_register(r1, alu_out);
-        SetS390ConditionCode<uint32_t>(alu_out, 0);
-      } else if (op == CLY) {
-        SetS390ConditionCode<uint32_t>(alu_out, mem_val);
-      }
-      break;
-    }
-    case AGFI:
-    case AFI: {
-      // Clobbering Add Word Immediate
-      RILInstruction* rilInstr = reinterpret_cast<RILInstruction*>(instr);
-      int32_t r1 = rilInstr->R1Value();
-      bool isOF = false;
-      if (AFI == op) {
-        // 32-bit Add (Register + 32-bit Immediate)
-        int32_t r1_val = get_low_register<int32_t>(r1);
-        int32_t i2 = rilInstr->I2Value();
-        isOF = CheckOverflowForIntAdd(r1_val, i2, int32_t);
-        int32_t alu_out = r1_val + i2;
-        set_low_register(r1, alu_out);
-        SetS390ConditionCode<int32_t>(alu_out, 0);
-      } else if (AGFI == op) {
-        // 64-bit Add (Register + 32-bit Imm)
-        int64_t r1_val = get_register(r1);
-        int64_t i2 = static_cast<int64_t>(rilInstr->I2Value());
-        isOF = CheckOverflowForIntAdd(r1_val, i2, int64_t);
-        int64_t alu_out = r1_val + i2;
-        set_register(r1, alu_out);
-        SetS390ConditionCode<int64_t>(alu_out, 0);
-      }
-      SetS390OverflowCode(isOF);
-      break;
-    }
-    case ASI: {
-      // TODO(bcleung): Change all fooInstr->I2Value() to template functions.
-      // The below static cast to 8 bit and then to 32 bit is necessary
-      // because siyInstr->I2Value() returns a uint8_t, which a direct
-      // cast to int32_t could incorrectly interpret.
-      int8_t i2_8bit = static_cast<int8_t>(siyInstr->I2Value());
-      int32_t i2 = static_cast<int32_t>(i2_8bit);
-      int b1 = siyInstr->B1Value();
-      intptr_t b1_val = (b1 == 0) ? 0 : get_register(b1);
-
-      int d1_val = siyInstr->D1Value();
-      intptr_t addr = b1_val + d1_val;
-
-      int32_t mem_val = ReadW(addr, instr);
-      bool isOF = CheckOverflowForIntAdd(mem_val, i2, int32_t);
-      int32_t alu_out = mem_val + i2;
-      SetS390ConditionCode<int32_t>(alu_out, 0);
-      SetS390OverflowCode(isOF);
-      WriteW(addr, alu_out, instr);
-      break;
-    }
-    case AGSI: {
-      // TODO(bcleung): Change all fooInstr->I2Value() to template functions.
-      // The below static cast to 8 bit and then to 32 bit is necessary
-      // because siyInstr->I2Value() returns a uint8_t, which a direct
-      // cast to int32_t could incorrectly interpret.
-      int8_t i2_8bit = static_cast<int8_t>(siyInstr->I2Value());
-      int64_t i2 = static_cast<int64_t>(i2_8bit);
-      int b1 = siyInstr->B1Value();
-      intptr_t b1_val = (b1 == 0) ? 0 : get_register(b1);
-
-      int d1_val = siyInstr->D1Value();
-      intptr_t addr = b1_val + d1_val;
-
-      int64_t mem_val = ReadDW(addr);
-      int isOF = CheckOverflowForIntAdd(mem_val, i2, int64_t);
-      int64_t alu_out = mem_val + i2;
-      SetS390ConditionCode<uint64_t>(alu_out, 0);
-      SetS390OverflowCode(isOF);
-      WriteDW(addr, alu_out);
-      break;
-    }
-    case AGF:
-    case SGF:
-    case ALG:
-    case SLG: {
-#ifndef V8_TARGET_ARCH_S390X
-      DCHECK(false);
-#endif
-      RXYInstruction* rxyInstr = reinterpret_cast<RXYInstruction*>(instr);
-      int r1 = rxyInstr->R1Value();
-      uint64_t r1_val = get_register(rxyInstr->R1Value());
-      int b2 = rxyInstr->B2Value();
-      int x2 = rxyInstr->X2Value();
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxyInstr->D2Value();
-      uint64_t alu_out = r1_val;
-      if (op == ALG) {
-        uint64_t mem_val =
-            static_cast<uint64_t>(ReadDW(b2_val + d2_val + x2_val));
-        alu_out += mem_val;
-        SetS390ConditionCode<uint64_t>(alu_out, 0);
-      } else if (op == SLG) {
-        uint64_t mem_val =
-            static_cast<uint64_t>(ReadDW(b2_val + d2_val + x2_val));
-        alu_out -= mem_val;
-        SetS390ConditionCode<uint64_t>(alu_out, 0);
-      } else if (op == AGF) {
-        uint32_t mem_val = ReadW(b2_val + d2_val + x2_val, instr);
-        alu_out += mem_val;
-        SetS390ConditionCode<int64_t>(alu_out, 0);
-      } else if (op == SGF) {
-        uint32_t mem_val = ReadW(b2_val + d2_val + x2_val, instr);
-        alu_out -= mem_val;
-        SetS390ConditionCode<int64_t>(alu_out, 0);
-      } else {
-        DCHECK(false);
-      }
-      set_register(r1, alu_out);
-      break;
-    }
-    case ALGFI:
-    case SLGFI: {
-#ifndef V8_TARGET_ARCH_S390X
-      // should only be called on 64bit
-      DCHECK(false);
-#endif
-      RILInstruction* rilInstr = reinterpret_cast<RILInstruction*>(instr);
-      int r1 = rilInstr->R1Value();
-      uint32_t i2 = rilInstr->I2UnsignedValue();
-      uint64_t r1_val = (uint64_t)(get_register(r1));
-      uint64_t alu_out;
-      if (op == ALGFI)
-        alu_out = r1_val + i2;
-      else
-        alu_out = r1_val - i2;
-      set_register(r1, (intptr_t)alu_out);
-      SetS390ConditionCode<uint64_t>(alu_out, 0);
-      break;
-    }
-    case MSY:
-    case MSG: {
-      RXYInstruction* rxyInstr = reinterpret_cast<RXYInstruction*>(instr);
-      int r1 = rxyInstr->R1Value();
-      int b2 = rxyInstr->B2Value();
-      int x2 = rxyInstr->X2Value();
-      int64_t b2_val = (b2 == 0) ? 0 : get_register(b2);
-      int64_t x2_val = (x2 == 0) ? 0 : get_register(x2);
-      intptr_t d2_val = rxyInstr->D2Value();
-      if (op == MSY) {
-        int32_t mem_val = ReadW(b2_val + d2_val + x2_val, instr);
-        int32_t r1_val = get_low_register<int32_t>(r1);
-        set_low_register(r1, mem_val * r1_val);
-      } else if (op == MSG) {
-        int64_t mem_val = ReadDW(b2_val + d2_val + x2_val);
-        int64_t r1_val = get_register(r1);
-        set_register(r1, mem_val * r1_val);
-      } else {
-        UNREACHABLE();
-      }
-      break;
-    }
-    case MSFI:
-    case MSGFI: {
-      RILInstruction* rilinst = reinterpret_cast<RILInstruction*>(instr);
-      int r1 = rilinst->R1Value();
-      int32_t i2 = rilinst->I2Value();
-      if (op == MSFI) {
-        int32_t alu_out = get_low_register<int32_t>(r1);
-        alu_out = alu_out * i2;
-        set_low_register(r1, alu_out);
-      } else if (op == MSGFI) {
-        int64_t alu_out = get_register(r1);
-        alu_out = alu_out * i2;
-        set_register(r1, alu_out);
-      } else {
-        UNREACHABLE();
-      }
-      break;
-    }
-    default:
-      UNREACHABLE();
-      return false;
-  }
-  return true;
-}
-
 int16_t Simulator::ByteReverse(int16_t hword) {
 #if defined(__GNUC__)
   return __builtin_bswap16(hword);
@@ -5583,18 +2440,6 @@ int64_t Simulator::ByteReverse(int64_t dword) {
 #endif
 }
 
-int Simulator::DecodeInstructionOriginal(Instruction* instr) {
-  int instrLength = instr->InstructionLength();
-  bool processed = true;
-  if (instrLength == 2)
-    processed = DecodeTwoByte(instr);
-  else if (instrLength == 4)
-    processed = DecodeFourByte(instr);
-  else if (instrLength == 6)
-    processed = DecodeSixByte(instr);
-  return instrLength;
-}
-
 int Simulator::DecodeInstruction(Instruction* instr) {
   Opcode op = instr->S390OpcodeValue();
   DCHECK(EvalTable[op] != NULL);