[x64] Introduce BMI instructions.

src/x64/macro-assembler-x64.cc

 // Copyright 2012 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/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
@@ skipping 2867 matching lines @@
     punpckldq(dst, xmm0);
   } else {
     DCHECK_EQ(0, imm8);
     psrlq(dst, 32);
     punpckldq(xmm0, dst);
     movaps(dst, xmm0);
   }
 }
 
 
-void MacroAssembler::Lzcntl(Register dst, Register src) {
-  // TODO(intel): Add support for LZCNT (BMI1/ABM).

[Benedikt Meurer, 2015/04/08 05:45:41]

Keep these functions, because not all machines will support lzcnt. What I meant
was to extend these functions with a special case for LZCNT, i.e.

if (CpuFeatures::IsSupported(LZCNT)) {
  lzcnt(dst, src);
} else {
  old code;
}

-  Label not_zero_src;
-  bsrl(dst, src);
-  j(not_zero, &not_zero_src, Label::kNear);
-  Set(dst, 63);  // 63^31 == 32
-  bind(&not_zero_src);
-  xorl(dst, Immediate(31));  // for x in [0..31], 31^x == 31 - x
-}
-
-
-void MacroAssembler::Lzcntl(Register dst, const Operand& src) {
-  // TODO(intel): Add support for LZCNT (BMI1/ABM).
-  Label not_zero_src;
-  bsrl(dst, src);
-  j(not_zero, &not_zero_src, Label::kNear);
-  Set(dst, 63);  // 63^31 == 32
-  bind(&not_zero_src);
-  xorl(dst, Immediate(31));  // for x in [0..31], 31^x == 31 - x
-}
-
-
 void MacroAssembler::Pushad() {
   Push(rax);
   Push(rcx);
   Push(rdx);
   Push(rbx);
   // Not pushing rsp or rbp.
   Push(rsi);
   Push(rdi);
   Push(r8);
   Push(r9);
@@ skipping 2164 matching lines @@
   if (mag.shift > 0) sarl(rdx, Immediate(mag.shift));
   movl(rax, dividend);
   shrl(rax, Immediate(31));
   addl(rdx, rax);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64