Update DecodeFieldToSmi to support x32 port.

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index a5a03f6aca2e0555a5b9b4b288a721cd788ab5fe..52209227c9e2602360020c64de5994d3db7f1a29 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -1022,8 +1022,22 @@ class MacroAssembler: public Assembler {
 
   template<typename Field>
   void DecodeFieldToSmi(Register reg) {
-    andp(reg, Immediate(Field::kMask));
-    shlp(reg, Immediate(kSmiShift - Field::kShift));
+    if (SmiValuesAre32Bits()) {
+      andp(reg, Immediate(Field::kMask));
+      shlp(reg, Immediate(kSmiShift - Field::kShift));
+    } else {
+      static const int shift = Field::kShift;
+      static const int mask = (Field::kMask >> Field::kShift) << kSmiTagSize;

[haitao.feng, 2014/06/09 05:43:06]

Clang reports an error when using kSmiShift:

    .././src/x64/macro-assembler-x64.h:1061:63: error: shift count >= width of
type [-Werror,-Wshift-count-overflow]
        static const int mask = (Field::kMask >> Field::kShift) << kSmiShift;

Windows reports a similar error. So I changed the kSmiShift to kSmiTagSize.

+      ASSERT(SmiValuesAre31Bits());
+      ASSERT(kSmiShift == kSmiTagSize);
+      ASSERT((mask & 0x80000000u) == 0);
+      if (shift < kSmiShift) {
+        shlp(reg, Immediate(kSmiShift - shift));
+      } else if (shift > kSmiShift) {
+        sarp(reg, Immediate(shift - kSmiShift));
+      }
+      andp(reg, Immediate(mask));
+    }
   }
 
   // Abort execution if argument is not a number, enabled via --debug-code.