Add custom typed ICs for pixel array loads.

src/ia32/ic-ia32.cc

Index: src/ia32/ic-ia32.cc
===================================================================
--- src/ia32/ic-ia32.cc	(revision 6456)
+++ src/ia32/ic-ia32.cc	(working copy)
@@ -760,6 +760,44 @@
 }
 
 
+void KeyedLoadIC::GeneratePixelArray(MacroAssembler* masm) {
+  // ----------- S t a t e -------------
+  //  -- eax    : key
+  //  -- edx    : receiver
+  //  -- esp[0] : return address
+  // -----------------------------------
+  Label slow;
+
+  // Check that the receiver isn't a smi.
+  __ test(edx, Immediate(kSmiTagMask));
+  __ j(zero, &slow, not_taken);
+
+  // Check that the key is an array index, that is Uint32.

[Mads Ager (chromium), 2011/01/25 14:49:17]

This code looks more complicated than on ARM and IA32. Not sure I understand why
this code would be faster than using basically the same code as on x64?

[danno, 2011/01/25 20:56:29]

Done.

+  __ test(eax, Immediate(kSmiTagMask | kSmiSignMask));
+  __ j(not_zero, &slow, not_taken);
+
+  // Get the map of the receiver.
+  __ mov(ecx, FieldOperand(edx, HeapObject::kMapOffset));
+
+  // Check whether the elements is a pixel array.
+  // edx: receiver
+  // eax: key
+  __ mov(ebx, eax);
+  __ SmiUntag(ebx);
+  __ mov(ecx, FieldOperand(edx, JSObject::kElementsOffset));

[Mads Ager (chromium), 2011/01/25 14:49:17]

Need a JSObject check.

[danno, 2011/01/25 20:56:29]

Done.

+  __ CheckMap(ecx, Factory::pixel_array_map(), &slow, true);
+  __ cmp(ebx, FieldOperand(ecx, PixelArray::kLengthOffset));
+  __ j(above_equal, &slow);
+  __ mov(eax, FieldOperand(ecx, PixelArray::kExternalPointerOffset));
+  __ movzx_b(eax, Operand(eax, ebx, times_1, 0));
+  __ SmiTag(eax);
+  __ ret(0);
+
+  __ bind(&slow);
+  GenerateMiss(masm);
+}
+
+
 void KeyedStoreIC::GenerateGeneric(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- eax    : value