MIPS: [turbofan] Implement Word32Ctz, Word64Ctz, Word32Popcnt and Word64Popcnt

src/compiler/mips/code-generator-mips.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ast/scopes.h"
 #include "src/compiler/code-generator.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/osr.h"
@@ skipping 670 matching lines @@
         DCHECK(i.InputOperand(1).immediate() == 0);
         __ Nor(i.OutputRegister(), i.InputRegister(0), zero_reg);
       }
       break;
     case kMipsXor:
       __ Xor(i.OutputRegister(), i.InputRegister(0), i.InputOperand(1));
       break;
     case kMipsClz:
       __ Clz(i.OutputRegister(), i.InputRegister(0));
       break;
+    case kMipsCtz: {
+      Register reg1 = kScratchReg;
+      Register reg2 = kScratchReg2;
+      Label skip_for_zero;
+      Label end;
+      // Branch if the operand is zero
+      __ Branch(&skip_for_zero, eq, i.InputRegister(0), Operand(zero_reg));
+      // Find the number of bits before the last bit set to 1.
+      __ Subu(reg2, zero_reg, i.InputRegister(0));
+      __ And(reg2, reg2, i.InputRegister(0));
+      __ clz(reg2, reg2);
+      // Get the number of bits after the last bit set to 1.
+      __ li(reg1, 0x1F);
+      __ Subu(i.OutputRegister(), reg1, reg2);
+      __ Branch(&end);
+      __ bind(&skip_for_zero);
+      // If the operand is zero, return word length as the result.
+      __ li(i.OutputRegister(), 0x20);
+      __ bind(&end);
+    } break;
+    case kMipsPopcnt: {
+      Register reg1 = kScratchReg;
+      Register reg2 = kScratchReg2;
+      uint32_t m1 = 0x55555555;
+      uint32_t m2 = 0x33333333;
+      uint32_t m4 = 0x0f0f0f0f;
+      uint32_t m8 = 0x00ff00ff;
+      uint32_t m16 = 0x0000ffff;
+
+      // Put count of ones in every 2 bits into those 2 bits.
+      __ li(at, m1);
+      __ srl(reg1, i.InputRegister(0), 1);
+      __ And(reg2, i.InputRegister(0), at);
+      __ And(reg1, reg1, at);
+      __ addu(reg1, reg1, reg2);
+
+      // Put count of ones in every 4 bits into those 4 bits.
+      __ li(at, m2);
+      __ srl(reg2, reg1, 2);
+      __ And(reg2, reg2, at);
+      __ And(reg1, reg1, at);
+      __ addu(reg1, reg1, reg2);
+
+      // Put count of ones in every 8 bits into those 8 bits.
+      __ li(at, m4);
+      __ srl(reg2, reg1, 4);
+      __ And(reg2, reg2, at);
+      __ And(reg1, reg1, at);
+      __ addu(reg1, reg1, reg2);
+
+      // Put count of ones in every 16 bits into those 16 bits.
+      __ li(at, m8);
+      __ srl(reg2, reg1, 8);
+      __ And(reg2, reg2, at);
+      __ And(reg1, reg1, at);
+      __ addu(reg1, reg1, reg2);
+
+      // Calculate total number of ones.
+      __ li(at, m16);
+      __ srl(reg2, reg1, 16);
+      __ And(reg2, reg2, at);
+      __ And(reg1, reg1, at);
+      __ addu(i.OutputRegister(), reg1, reg2);
+    } break;
     case kMipsShl:
       if (instr->InputAt(1)->IsRegister()) {
         __ sllv(i.OutputRegister(), i.InputRegister(0), i.InputRegister(1));
       } else {
         int32_t imm = i.InputOperand(1).immediate();
         __ sll(i.OutputRegister(), i.InputRegister(0), imm);
       }
       break;
     case kMipsShr:
       if (instr->InputAt(1)->IsRegister()) {
@@ skipping 1043 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8