MIPS port initial commit

src/mips/macro-assembler-mips.cc

+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+
+#include "v8.h"
+
+#include "bootstrapper.h"
+#include "codegen-inl.h"
+#include "debug.h"
+#include "runtime.h"
+
+namespace v8 {
+namespace internal {
+
+MacroAssembler::MacroAssembler(void* buffer, int size)
+    : Assembler(buffer, size),
+      unresolved_(0),
+      generating_stub_(false),
+      allow_stub_calls_(true),
+      code_object_(Heap::undefined_value()) {
+}
+
+
+
+void MacroAssembler::Jump(Register target, Condition cond,
+                          Register r1, const Operand& r2) {
+  Jump(Operand(target), cond, r1, r2);
+}
+
+
+void MacroAssembler::Jump(intptr_t target, RelocInfo::Mode rmode,
+                          Condition cond, Register r1, const Operand& r2) {
+  Jump(Operand(target), cond, r1, r2);
+}
+
+
+void MacroAssembler::Jump(byte* target, RelocInfo::Mode rmode,
+                          Condition cond, Register r1, const Operand& r2) {
+  ASSERT(!RelocInfo::IsCodeTarget(rmode));
+  Jump(reinterpret_cast<intptr_t>(target), rmode, cond, r1, r2);
+}
+
+
+void MacroAssembler::Jump(Handle<Code> code, RelocInfo::Mode rmode,
+                          Condition cond, Register r1, const Operand& r2) {
+  ASSERT(RelocInfo::IsCodeTarget(rmode));
+  Jump(reinterpret_cast<intptr_t>(code.location()), rmode, cond);
+}
+
+
+void MacroAssembler::Call(Register target,
+                          Condition cond, Register r1, const Operand& r2) {
+  Call(Operand(target), cond, r1, r2);
+}
+
+
+void MacroAssembler::Call(intptr_t target, RelocInfo::Mode rmode,
+                          Condition cond, Register r1, const Operand& r2) {
+  Call(Operand(target), cond, r1, r2);
+}
+
+
+void MacroAssembler::Call(byte* target, RelocInfo::Mode rmode,
+                          Condition cond, Register r1, const Operand& r2) {
+  ASSERT(!RelocInfo::IsCodeTarget(rmode));
+  Call(reinterpret_cast<intptr_t>(target), rmode, cond, r1, r2);
+}
+
+
+void MacroAssembler::Call(Handle<Code> code, RelocInfo::Mode rmode,
+                          Condition cond, Register r1, const Operand& r2) {
+  ASSERT(RelocInfo::IsCodeTarget(rmode));
+  Call(reinterpret_cast<intptr_t>(code.location()), rmode, cond, r1, r2);
+}
+
+
+void MacroAssembler::Ret(Condition cond, Register r1, const Operand& r2) {
+  Jump(Operand(ra), cond, r1, r2);
+}
+
+
+void MacroAssembler::LoadRoot(Register destination,
+                              Heap::RootListIndex index) {
+  lw(destination, MemOperand(s4, index << kPointerSizeLog2));
+}
+
+void MacroAssembler::LoadRoot(Register destination,
+                              Heap::RootListIndex index,
+                              Condition cond,
+                              Register src1, const Operand& src2) {
+  Branch(NegateCondition(cond), 2, src1, src2);
+  nop();
+  lw(destination, MemOperand(s4, index << kPointerSizeLog2));
+}
+
+
+void MacroAssembler::RecordWrite(Register object, Register offset,
+                                 Register scratch) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+// ---------------------------------------------------------------------------
+// Instruction macros
+
+void MacroAssembler::Add(Register rd, Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    add(rd, rs, rt.rm());
+  } else {
+    if (is_int16(rt.imm32_) && !MustUseAt(rt.rmode_)) {
+      addi(rd, rs, rt.imm32_);
+    } else {
+      // li handles the relocation.
+      ASSERT(!rs.is(at));
+      li(at, rt);
+      add(rd, rs, at);
+    }
+  }
+}
+
+
+void MacroAssembler::Addu(Register rd, Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    addu(rd, rs, rt.rm());
+  } else {
+    if (is_int16(rt.imm32_) && !MustUseAt(rt.rmode_)) {
+      addiu(rd, rs, rt.imm32_);
+    } else {
+      // li handles the relocation.
+      ASSERT(!rs.is(at));
+      li(at, rt);
+      addu(rd, rs, at);
+    }
+  }
+}
+
+
+void MacroAssembler::Mul(Register rd, Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    mul(rd, rs, rt.rm());
+  } else {
+    // li handles the relocation.
+    ASSERT(!rs.is(at));
+    li(at, rt);
+    mul(rd, rs, at);
+  }
+}
+
+
+void MacroAssembler::Mult(Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    mult(rs, rt.rm());
+  } else {
+    // li handles the relocation.
+    ASSERT(!rs.is(at));
+    li(at, rt);
+    mult(rs, at);
+  }
+}
+
+
+void MacroAssembler::Multu(Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    multu(rs, rt.rm());
+  } else {
+    // li handles the relocation.
+    ASSERT(!rs.is(at));
+    li(at, rt);
+    multu(rs, at);
+  }
+}
+
+
+void MacroAssembler::Div(Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    div(rs, rt.rm());
+  } else {
+    // li handles the relocation.
+    ASSERT(!rs.is(at));
+    li(at, rt);
+    div(rs, at);
+  }
+}
+
+
+void MacroAssembler::Divu(Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    divu(rs, rt.rm());
+  } else {
+    // li handles the relocation.
+    ASSERT(!rs.is(at));
+    li(at, rt);
+    divu(rs, at);
+  }
+}
+
+
+void MacroAssembler::And(Register rd, Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    and_(rd, rs, rt.rm());
+  } else {
+    if (is_int16(rt.imm32_) && !MustUseAt(rt.rmode_)) {
+      andi(rd, rs, rt.imm32_);
+    } else {
+      // li handles the relocation.
+      ASSERT(!rs.is(at));
+      li(at, rt);
+      and_(rd, rs, at);
+    }
+  }
+}
+
+
+void MacroAssembler::Or(Register rd, Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    or_(rd, rs, rt.rm());
+  } else {
+    if (is_int16(rt.imm32_) && !MustUseAt(rt.rmode_)) {
+      ori(rd, rs, rt.imm32_);
+    } else {
+      // li handles the relocation.
+      ASSERT(!rs.is(at));
+      li(at, rt);
+      or_(rd, rs, at);
+    }
+  }
+}
+
+
+void MacroAssembler::Xor(Register rd, Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    xor_(rd, rs, rt.rm());
+  } else {
+    if (is_int16(rt.imm32_) && !MustUseAt(rt.rmode_)) {
+      xori(rd, rs, rt.imm32_);
+    } else {
+      // li handles the relocation.
+      ASSERT(!rs.is(at));
+      li(at, rt);
+      xor_(rd, rs, at);
+    }
+  }
+}
+
+
+void MacroAssembler::Nor(Register rd, Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    nor(rd, rs, rt.rm());
+  } else {
+    // li handles the relocation.
+    ASSERT(!rs.is(at));
+    li(at, rt);
+    nor(rd, rs, at);
+  }
+}
+
+
+void MacroAssembler::Slt(Register rd, Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    slt(rd, rs, rt.rm());
+  } else {
+    if (is_int16(rt.imm32_) && !MustUseAt(rt.rmode_)) {
+      slti(rd, rs, rt.imm32_);
+    } else {
+      // li handles the relocation.
+      ASSERT(!rs.is(at));
+      li(at, rt);
+      slt(rd, rs, at);
+    }
+  }
+}
+
+
+void MacroAssembler::Sltu(Register rd, Register rs, const Operand& rt) {
+  if (rt.is_reg()) {
+    sltu(rd, rs, rt.rm());
+  } else {
+    if (is_int16(rt.imm32_) && !MustUseAt(rt.rmode_)) {
+      sltiu(rd, rs, rt.imm32_);
+    } else {
+      // li handles the relocation.
+      ASSERT(!rs.is(at));
+      li(at, rt);
+      sltu(rd, rs, at);
+    }
+  }
+}
+
+
+//------------Pseudo-instructions-------------
+
+void MacroAssembler::movn(Register rd, Register rt) {
+  addiu(at, zero_reg, -1);  // Fill at with ones.
+  xor_(rd, rt, at);
+}
+
+
+// load wartd in a register
+void MacroAssembler::li(Register rd, Operand j, bool gen2instr) {
+  ASSERT(!j.is_reg());
+
+  if (!MustUseAt(j.rmode_) && !gen2instr) {
+    // Normal load of an immediate value which does not need Relocation Info.
+    if (is_int16(j.imm32_)) {
+      addiu(rd, zero_reg, j.imm32_);
+    } else if (!(j.imm32_ & HIMask)) {
+      ori(rd, zero_reg, j.imm32_);
+    } else if (!(j.imm32_ & LOMask)) {
+      lui(rd, (HIMask & j.imm32_) >> 16);
+    } else {
+      lui(rd, (HIMask & j.imm32_) >> 16);
+      ori(rd, rd, (LOMask & j.imm32_));
+    }
+  } else if (MustUseAt(j.rmode_) || gen2instr) {
+    if (MustUseAt(j.rmode_)) {
+      RecordRelocInfo(j.rmode_, j.imm32_);
+    }
+    // We need always the same number of instructions as we may need to patch
+    // this code to load another value which may need 2 instructions to load.
+    if (is_int16(j.imm32_)) {
+      nop();
+      addiu(rd, zero_reg, j.imm32_);
+    } else if (!(j.imm32_ & HIMask)) {
+      nop();
+      ori(rd, zero_reg, j.imm32_);
+    } else if (!(j.imm32_ & LOMask)) {
+      nop();
+      lui(rd, (HIMask & j.imm32_) >> 16);
+    } else {
+      lui(rd, (HIMask & j.imm32_) >> 16);
+      ori(rd, rd, (LOMask & j.imm32_));
+    }
+  }
+}
+
+
+// Exception-generating instructions and debugging support
+void MacroAssembler::stop(const char* msg) {
+  // TO_UPGRADE: Just a break for now. Maybe we could upgrade it.
+  // We use the 0x54321 value to be able to find it easily when reading memory.
+  break_(0x54321);
+}
+
+
+void MacroAssembler::MultiPush(RegList regs) {
+  int16_t NumSaved = 0;
+  int16_t NumToPush = NumberOfBitsSet(regs);
+
+  addiu(sp, sp, -4 * NumToPush);
+  for (int16_t i = 0; i < kNumRegisters; i++) {
+    if ((regs & (1 << i)) != 0) {
+      sw(ToRegister(i), MemOperand(sp, 4 * (NumToPush - ++NumSaved)));
+    }
+  }
+}
+
+
+void MacroAssembler::MultiPushReversed(RegList regs) {
+  int16_t NumSaved = 0;
+  int16_t NumToPush = NumberOfBitsSet(regs);
+
+  addiu(sp, sp, -4 * NumToPush);
+  for (int16_t i = kNumRegisters; i > 0; i--) {
+    if ((regs & (1 << i)) != 0) {
+      sw(ToRegister(i), MemOperand(sp, 4 * (NumToPush - ++NumSaved)));
+    }
+  }
+}
+
+
+void MacroAssembler::MultiPop(RegList regs) {
+  int16_t NumSaved = 0;
+
+  for (int16_t i = kNumRegisters; i > 0; i--) {
+    if ((regs & (1 << i)) != 0) {
+      lw(ToRegister(i), MemOperand(sp, 4 * (NumSaved++)));
+    }
+  }
+  addiu(sp, sp, 4 * NumSaved);
+}
+
+
+void MacroAssembler::MultiPopReversed(RegList regs) {
+  int16_t NumSaved = 0;
+
+  for (int16_t i = 0; i < kNumRegisters; i++) {
+    if ((regs & (1 << i)) != 0) {
+      lw(ToRegister(i), MemOperand(sp, 4 * (NumSaved++)));
+    }
+  }
+  addiu(sp, sp, 4 * NumSaved);
+}
+
+
+// Emulated condtional branches do not emit a nop in the branch delay slot.
+
+// Trashes the at register if no scratch register is provided.
+void MacroAssembler::Branch(Condition cond, int16_t offset, Register rs,
+                            const Operand& rt, Register scratch) {
+  Register r2;
+  if (rt.is_reg()) {
+    // We don't want any other register but scratch clobbered.
+    ASSERT(!scratch.is(rs) && !scratch.is(rt.rm_));
+    r2 = rt.rm_;
+  } else if (cond != cc_always) {
+    // We don't want any other register but scratch clobbered.
+    ASSERT(!scratch.is(rs));
+    r2 = scratch;
+    li(r2, rt);
+  }
+
+  switch (cond) {
+    case cc_always:
+      b(offset);
+      break;
+    case eq:
+      beq(rs, r2, offset);
+      break;
+    case ne:
+      bne(rs, r2, offset);
+      break;
+
+      // Signed comparison
+    case greater:
+      slt(scratch, r2, rs);
+      bne(scratch, zero_reg, offset);
+      break;
+    case greater_equal:
+      slt(scratch, rs, r2);
+      beq(scratch, zero_reg, offset);
+      break;
+    case less:
+      slt(scratch, rs, r2);
+      bne(scratch, zero_reg, offset);
+      break;
+    case less_equal:
+      slt(scratch, r2, rs);
+      beq(scratch, zero_reg, offset);
+      break;
+
+      // Unsigned comparison.
+    case Ugreater:
+      sltu(scratch, r2, rs);
+      bne(scratch, zero_reg, offset);
+      break;
+    case Ugreater_equal:
+      sltu(scratch, rs, r2);
+      beq(scratch, zero_reg, offset);
+      break;
+    case Uless:
+      sltu(scratch, rs, r2);
+      bne(scratch, zero_reg, offset);
+      break;
+    case Uless_equal:
+      sltu(scratch, r2, rs);
+      beq(scratch, zero_reg, offset);
+      break;
+
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+void MacroAssembler::Branch(Condition cond,  Label* L, Register rs,
+                            const Operand& rt, Register scratch) {
+  Register r2;
+  if (rt.is_reg()) {
+    r2 = rt.rm_;
+  } else if (cond != cc_always) {
+    r2 = scratch;
+    li(r2, rt);
+  }
+
+  // We use branch_offset as an argument for the branch instructions to be sure
+  // it is called just before generating the branch instruction, as needed.
+
+  switch (cond) {
+    case cc_always:
+      b(shifted_branch_offset(L, false));
+      break;
+    case eq:
+      beq(rs, r2, shifted_branch_offset(L, false));
+      break;
+    case ne:
+      bne(rs, r2, shifted_branch_offset(L, false));
+      break;
+
+    // Signed comparison
+    case greater:
+      slt(scratch, r2, rs);
+      bne(scratch, zero_reg, shifted_branch_offset(L, false));
+      break;
+    case greater_equal:
+      slt(scratch, rs, r2);
+      beq(scratch, zero_reg, shifted_branch_offset(L, false));
+      break;
+    case less:
+      slt(scratch, rs, r2);
+      bne(scratch, zero_reg, shifted_branch_offset(L, false));
+      break;
+    case less_equal:
+      slt(scratch, r2, rs);
+      beq(scratch, zero_reg, shifted_branch_offset(L, false));
+      break;
+
+    // Unsigned comparison.
+    case Ugreater:
+      sltu(scratch, r2, rs);
+      bne(scratch, zero_reg, shifted_branch_offset(L, false));
+      break;
+    case Ugreater_equal:
+      sltu(scratch, rs, r2);
+      beq(scratch, zero_reg, shifted_branch_offset(L, false));
+      break;
+    case Uless:
+      sltu(scratch, rs, r2);
+      bne(scratch, zero_reg, shifted_branch_offset(L, false));
+      break;
+    case Uless_equal:
+      sltu(scratch, r2, rs);
+      beq(scratch, zero_reg, shifted_branch_offset(L, false));
+      break;
+
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+// Trashes the at register if no scratch register is provided.
+// We need to use a bgezal or bltzal, but they can't be used directly with the
+// slt instructions. We could use sub or add instead but we would miss overflow
+// cases, so we keep slt and add an intermediate third instruction.
+void MacroAssembler::BranchAndLink(Condition cond, int16_t offset, Register rs,
+                                   const Operand& rt, Register scratch) {
+  Register r2;
+  if (rt.is_reg()) {
+    r2 = rt.rm_;
+  } else if (cond != cc_always) {
+    r2 = scratch;
+    li(r2, rt);
+  }
+
+  switch (cond) {
+    case cc_always:
+      bal(offset);
+      break;
+    case eq:
+      bne(rs, r2, 2);
+      nop();
+      bal(offset);
+      break;
+    case ne:
+      beq(rs, r2, 2);
+      nop();
+      bal(offset);
+      break;
+
+    // Signed comparison
+    case greater:
+      slt(scratch, r2, rs);
+      addiu(scratch, scratch, -1);
+      bgezal(scratch, offset);
+      break;
+    case greater_equal:
+      slt(scratch, rs, r2);
+      addiu(scratch, scratch, -1);
+      bltzal(scratch, offset);
+      break;
+    case less:
+      slt(scratch, rs, r2);
+      addiu(scratch, scratch, -1);
+      bgezal(scratch, offset);
+      break;
+    case less_equal:
+      slt(scratch, r2, rs);
+      addiu(scratch, scratch, -1);
+      bltzal(scratch, offset);
+      break;
+
+    // Unsigned comparison.
+    case Ugreater:
+      sltu(scratch, r2, rs);
+      addiu(scratch, scratch, -1);
+      bgezal(scratch, offset);
+      break;
+    case Ugreater_equal:
+      sltu(scratch, rs, r2);
+      addiu(scratch, scratch, -1);
+      bltzal(scratch, offset);
+      break;
+    case Uless:
+      sltu(scratch, rs, r2);
+      addiu(scratch, scratch, -1);
+      bgezal(scratch, offset);
+      break;
+    case Uless_equal:
+      sltu(scratch, r2, rs);
+      addiu(scratch, scratch, -1);
+      bltzal(scratch, offset);
+      break;
+
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+void MacroAssembler::BranchAndLink(Condition cond, Label* L, Register rs,
+                                   const Operand& rt, Register scratch) {
+  Register r2;
+  if (rt.is_reg()) {
+    r2 = rt.rm_;
+  } else if (cond != cc_always) {
+    r2 = scratch;
+    li(r2, rt);
+  }
+
+  switch (cond) {
+    case cc_always:
+      bal(shifted_branch_offset(L, false));
+      break;
+    case eq:
+      bne(rs, r2, 2);
+      nop();
+      bal(shifted_branch_offset(L, false));
+      break;
+    case ne:
+      beq(rs, r2, 2);
+      nop();
+      bal(shifted_branch_offset(L, false));
+      break;
+
+    // Signed comparison
+    case greater:
+      slt(scratch, r2, rs);
+      addiu(scratch, scratch, -1);
+      bgezal(scratch, shifted_branch_offset(L, false));
+      break;
+    case greater_equal:
+      slt(scratch, rs, r2);
+      addiu(scratch, scratch, -1);
+      bltzal(scratch, shifted_branch_offset(L, false));
+      break;
+    case less:
+      slt(scratch, rs, r2);
+      addiu(scratch, scratch, -1);
+      bgezal(scratch, shifted_branch_offset(L, false));
+      break;
+    case less_equal:
+      slt(scratch, r2, rs);
+      addiu(scratch, scratch, -1);
+      bltzal(scratch, shifted_branch_offset(L, false));
+      break;
+
+    // Unsigned comparison.
+    case Ugreater:
+      sltu(scratch, r2, rs);
+      addiu(scratch, scratch, -1);
+      bgezal(scratch, shifted_branch_offset(L, false));
+      break;
+    case Ugreater_equal:
+      sltu(scratch, rs, r2);
+      addiu(scratch, scratch, -1);
+      bltzal(scratch, shifted_branch_offset(L, false));
+      break;
+    case Uless:
+      sltu(scratch, rs, r2);
+      addiu(scratch, scratch, -1);
+      bgezal(scratch, shifted_branch_offset(L, false));
+      break;
+    case Uless_equal:
+      sltu(scratch, r2, rs);
+      addiu(scratch, scratch, -1);
+      bltzal(scratch, shifted_branch_offset(L, false));
+      break;
+
+    default:
+      UNREACHABLE();
+  }
+}
+
+
+void MacroAssembler::Jump(const Operand& target,
+                          Condition cond, Register rs, const Operand& rt) {
+  if (target.is_reg()) {
+    if (cond == cc_always) {
+      jr(target.rm());
+    } else {
+      Branch(NegateCondition(cond), 2, rs, rt);
+      nop();
+      jr(target.rm());
+    }
+  } else {    // !target.is_reg()
+    if (!MustUseAt(target.rmode_)) {
+      if (cond == cc_always) {
+        j(target.imm32_);
+      } else {
+        Branch(NegateCondition(cond), 2, rs, rt);
+        nop();
+        j(target.imm32_);  // will generate only one instruction.
+      }
+    } else {  // MustUseAt(target)
+      li(at, rt);
+      if (cond == cc_always) {
+        jr(at);
+      } else {
+        Branch(NegateCondition(cond), 2, rs, rt);
+        nop();
+        jr(at);  // will generate only one instruction.
+      }
+    }
+  }
+}
+
+
+void MacroAssembler::Call(const Operand& target,
+                          Condition cond, Register rs, const Operand& rt) {
+  if (target.is_reg()) {
+    if (cond == cc_always) {
+      jalr(target.rm());
+    } else {
+      Branch(NegateCondition(cond), 2, rs, rt);
+      nop();
+      jalr(target.rm());
+    }
+  } else {    // !target.is_reg()
+    if (!MustUseAt(target.rmode_)) {
+      if (cond == cc_always) {
+        jal(target.imm32_);
+      } else {
+        Branch(NegateCondition(cond), 2, rs, rt);
+        nop();
+        jal(target.imm32_);  // will generate only one instruction.
+      }
+    } else {  // MustUseAt(target)
+      li(at, rt);
+      if (cond == cc_always) {
+        jalr(at);
+      } else {
+        Branch(NegateCondition(cond), 2, rs, rt);
+        nop();
+        jalr(at);  // will generate only one instruction.
+      }
+    }
+  }
+}
+
+void MacroAssembler::StackLimitCheck(Label* on_stack_overflow) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::Drop(int count, Condition cond) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::Call(Label* target) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+// ---------------------------------------------------------------------------
+// Exception handling
+
+void MacroAssembler::PushTryHandler(CodeLocation try_location,
+                                    HandlerType type) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::PopTryHandler() {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+
+// ---------------------------------------------------------------------------
+// Activation frames
+
+void MacroAssembler::CallStub(CodeStub* stub, Condition cond,
+                              Register r1, const Operand& r2) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::StubReturn(int argc) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::CallRuntime(Runtime::Function* f, int num_arguments) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::CallRuntime(Runtime::FunctionId fid, int num_arguments) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::TailCallRuntime(const ExternalReference& ext,
+                                     int num_arguments,
+                                     int result_size) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::JumpToRuntime(const ExternalReference& builtin) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+Handle<Code> MacroAssembler::ResolveBuiltin(Builtins::JavaScript id,
+                                            bool* resolved) {
+  UNIMPLEMENTED_MIPS();
+  return Handle<Code>(reinterpret_cast<Code*>(NULL));   // UNIMPLEMENTED RETURN
+}
+
+
+void MacroAssembler::InvokeBuiltin(Builtins::JavaScript id,
+                                   InvokeJSFlags flags) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::GetBuiltinEntry(Register target, Builtins::JavaScript id) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::SetCounter(StatsCounter* counter, int value,
+                                Register scratch1, Register scratch2) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::IncrementCounter(StatsCounter* counter, int value,
+                                      Register scratch1, Register scratch2) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::DecrementCounter(StatsCounter* counter, int value,
+                                      Register scratch1, Register scratch2) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+
+void MacroAssembler::Assert(Condition cc, const char* msg,
+                            Register rs, Operand rt) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::Check(Condition cc, const char* msg,
+                           Register rs, Operand rt) {
+  UNIMPLEMENTED_MIPS();
+}
+
+
+void MacroAssembler::Abort(const char* msg) {
+  UNIMPLEMENTED_MIPS();
+}
+
+} }  // namespace v8::internal
+