X64: Many small tweaks and more usages of "load smi as int32".

Review URL: http://codereview.chromium.org/2266003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4739 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/x64/assembler-x64.h

@@ -307,7 +307,7 @@ class Operand BASE_EMBEDDED {
 
  private:
   byte rex_;
-  byte buf_[10];
+  byte buf_[6];
   // The number of bytes in buf_.
   unsigned int len_;
 

src/x64/ic-x64.cc

@@ -104,8 +104,7 @@ static void GenerateDictionaryLoad(MacroAssembler* masm,
   const int kCapacityOffset =
       StringDictionary::kHeaderSize +
       StringDictionary::kCapacityIndex * kPointerSize;
-  __ movq(r2, FieldOperand(r0, kCapacityOffset));
-  __ SmiToInteger32(r2, r2);
+  __ SmiToInteger32(r2, FieldOperand(r0, kCapacityOffset));
   __ decl(r2);
 
   // Generate an unrolled loop that performs a few probes before
@@ -202,8 +201,8 @@ static void GenerateNumberDictionaryLoad(MacroAssembler* masm,
   __ xorl(r0, r1);
 
   // Compute capacity mask.
-  __ movq(r1, FieldOperand(elements, NumberDictionary::kCapacityOffset));
-  __ SmiToInteger32(r1, r1);
+  __ SmiToInteger32(r1,
+                    FieldOperand(elements, NumberDictionary::kCapacityOffset));
   __ decl(r1);
 
   // Generate an unrolled loop that performs a few probes before giving up.

src/x64/macro-assembler-x64.cc

@@ -573,6 +573,11 @@ void MacroAssembler::SmiToInteger32(Register dst, Register src) {
 }
 
 
+void MacroAssembler::SmiToInteger32(Register dst, const Operand& src) {
+  movl(dst, Operand(src, kSmiShift / kBitsPerByte));
+}
+
+
 void MacroAssembler::SmiToInteger64(Register dst, Register src) {
   ASSERT_EQ(0, kSmiTag);
   if (!dst.is(src)) {
@@ -614,7 +619,7 @@ void MacroAssembler::SmiCompare(const Operand& dst, Register src) {
 
 
 void MacroAssembler::SmiCompare(const Operand& dst, Smi* src) {
-  cmpl(Operand(dst, kIntSize), Immediate(src->value()));
+  cmpl(Operand(dst, kSmiShift / kBitsPerByte), Immediate(src->value()));
 }
 
 
@@ -916,7 +921,7 @@ void MacroAssembler::SmiAddConstant(Register dst, Register src, Smi* constant) {
 
 void MacroAssembler::SmiAddConstant(const Operand& dst, Smi* constant) {
   if (constant->value() != 0) {
-    addl(Operand(dst, kIntSize), Immediate(constant->value()));
+    addl(Operand(dst, kSmiShift / kBitsPerByte), Immediate(constant->value()));
   }
 }
 

src/x64/macro-assembler-x64.h

@@ -210,6 +210,7 @@ class MacroAssembler: public Assembler {
   // Convert smi to 32-bit integer. I.e., not sign extended into
   // high 32 bits of destination.
   void SmiToInteger32(Register dst, Register src);
+  void SmiToInteger32(Register dst, const Operand& src);
 
   // Convert smi to 64-bit integer (sign extended if necessary).
   void SmiToInteger64(Register dst, Register src);