IA32: Avoid going into stubs or runtime code for bitops even if the...

src/ia32/macro-assembler-ia32.cc

Index: src/ia32/macro-assembler-ia32.cc
===================================================================
--- src/ia32/macro-assembler-ia32.cc	(revision 5165)
+++ src/ia32/macro-assembler-ia32.cc	(working copy)
@@ -377,6 +377,12 @@
 }
 
 
+void MacroAssembler::AbortIfSmi(Register object) {
+  test(object, Immediate(kSmiTagMask));
+  Assert(not_equal, "Operand a smi");
+}
+
+
 void MacroAssembler::EnterFrame(StackFrame::Type type) {
   push(ebp);
   mov(ebp, Operand(esp));
@@ -1497,6 +1503,45 @@
 }
 
 
+void MacroAssembler::JumpIfNotNumber(Register reg,
+                                     TypeInfo info,
+                                     Label* on_not_number) {
+  if (FLAG_debug_code) AbortIfSmi(reg);
+  if (!info.IsNumber()) {
+    cmp(FieldOperand(reg, HeapObject::kMapOffset),
+        Factory::heap_number_map());
+    j(not_equal, on_not_number);
+  }
+}
+
+
+void MacroAssembler::JumpIfNotInt32(Register reg,
+                                    Register scratch,
+                                    TypeInfo info,
+                                    Label* on_not_int32) {
+  if (FLAG_debug_code) {
+    AbortIfSmi(reg);
+    AbortIfNotNumber(reg);
+  }
+  const uint32_t non_smi_exponent =
+      (HeapNumber::kExponentBias + 30) << HeapNumber::kExponentShift;
+  if (!info.IsInteger32()) {
+    bool push_pop = scratch.is(no_reg);
+    if (push_pop) {
+      push(reg);
+      scratch = reg;
+    }
+    mov(scratch, FieldOperand(reg, HeapNumber::kExponentOffset));
+    and_(scratch, HeapNumber::kExponentMask);
+    cmp(scratch, non_smi_exponent);
+    if (push_pop) {
+      pop(reg);
+    }
+    j(greater, on_not_int32);

[Lasse Reichstein, 2010/08/06 08:20:12]

Is this faster than using SSE2 cvttsd2si and checking against 0x8000000? Even if
it is, using cvttsd2si would also give the 32-bit number as a result
immediately, instead of first doing this test and then converting afterwards, as
it seemed was the typical use of this function.
E.g., I'm suggesting a: 
 NumberToInt32(Register dst, Register src, TypeInfo info, Label* on_not_int32)

[Erik Corry, 2010/08/09 13:13:49]

Done.

+  }
+}
+
+
 void MacroAssembler::JumpIfInstanceTypeIsNotSequentialAscii(
     Register instance_type,
     Register scratch,