CTZ instruction implemented as optional operator.

src/x64/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/x64/assembler-x64.h"
 
 #include <cstring>
 
 #if V8_TARGET_ARCH_X64
 
@@ skipping 727 matching lines @@
 
 void Assembler::bsrl(Register dst, const Operand& src) {
   EnsureSpace ensure_space(this);
   emit_optional_rex_32(dst, src);
   emit(0x0F);
   emit(0xBD);
   emit_operand(dst, src);
 }
 
 
+void Assembler::bsfl(Register dst, Register src) {
+  EnsureSpace ensure_space(this);
+  emit_optional_rex_32(dst, src);
+  emit(0x0F);
+  emit(0xBC);
+  emit_modrm(dst, src);
+}
+
+
+void Assembler::bsfl(Register dst, const Operand& src) {
+  EnsureSpace ensure_space(this);
+  emit_optional_rex_32(dst, src);
+  emit(0x0F);
+  emit(0xBC);
+  emit_operand(dst, src);
+}
+
+
 void Assembler::call(Label* L) {
   positions_recorder()->WriteRecordedPositions();
   EnsureSpace ensure_space(this);
   // 1110 1000 #32-bit disp.
   emit(0xE8);
   if (L->is_bound()) {
     int offset = L->pos() - pc_offset() - sizeof(int32_t);
     DCHECK(offset <= 0);
     emitl(offset);
   } else if (L->is_linked()) {
@@ skipping 3171 matching lines @@
 
 bool RelocInfo::IsInConstantPool() {
   return false;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64