X64: Use sahf instruction only on processors that support it.

src/x64/codegen-x64.cc

 // Copyright 2009 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
@@ skipping 7704 matching lines @@
         __ fisttp_s(Operand(rsp, 1 * kPointerSize));
         __ fnstsw_ax();
         __ testl(rax, Immediate(1));
         __ j(not_zero, &operand_conversion_failure);
       } else {
         // Check if right operand is int32.
         __ fist_s(Operand(rsp, 0 * kPointerSize));
         __ fild_s(Operand(rsp, 0 * kPointerSize));
         __ fucompp();
         __ fnstsw_ax();
-        __ sahf();  // TODO(X64): Not available.
-        __ j(not_zero, &operand_conversion_failure);
-        __ j(parity_even, &operand_conversion_failure);
-
+        if (CpuFeatures::IsSupported(CpuFeatures::SAHF)) {
+          __ sahf();
+          __ j(not_zero, &operand_conversion_failure);
+          __ j(parity_even, &operand_conversion_failure);
+        } else {
+          __ and_(rax, Immediate(0x4400));
+          __ cmpl(rax, Immediate(0x4000));
+          __ j(not_zero, &operand_conversion_failure);
+        }
         // Check if left operand is int32.
         __ fist_s(Operand(rsp, 1 * kPointerSize));
         __ fild_s(Operand(rsp, 1 * kPointerSize));
         __ fucompp();
         __ fnstsw_ax();
-        __ sahf();  // TODO(X64): Not available. Test bits in ax directly
-        __ j(not_zero, &operand_conversion_failure);
-        __ j(parity_even, &operand_conversion_failure);
+        if (CpuFeatures::IsSupported(CpuFeatures::SAHF)) {
+          __ sahf();
+          __ j(not_zero, &operand_conversion_failure);
+          __ j(parity_even, &operand_conversion_failure);
+        } else {
+          __ and_(rax, Immediate(0x4400));
+          __ cmpl(rax, Immediate(0x4000));
+          __ j(not_zero, &operand_conversion_failure);
+        }
       }
 
       // Get int32 operands and perform bitop.
       __ pop(rcx);
       __ pop(rax);
       switch (op_) {
         case Token::BIT_OR:  __ or_(rax, rcx); break;
         case Token::BIT_AND: __ and_(rax, rcx); break;
         case Token::BIT_XOR: __ xor_(rax, rcx); break;
         case Token::SAR: __ sarl(rax); break;
@@ skipping 117 matching lines @@
 int CompareStub::MinorKey() {
   // Encode the two parameters in a unique 16 bit value.
   ASSERT(static_cast<unsigned>(cc_) < (1 << 15));
   return (static_cast<unsigned>(cc_) << 1) | (strict_ ? 1 : 0);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal