Support conversion of clamped double values for pixel arrays in Crankshaft.

src/x64/lithium-codegen-x64.cc

 // Copyright 2011 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 3167 matching lines @@
   if (array_type == kExternalFloatArray) {
     XMMRegister value(ToDoubleRegister(instr->value()));
     __ cvtsd2ss(value, value);
     __ movss(operand, value);
   } else if (array_type == kExternalDoubleArray) {
     __ movsd(operand, ToDoubleRegister(instr->value()));
   } else {
     Register value(ToRegister(instr->value()));
     switch (array_type) {
       case kExternalPixelArray:
         {  // Clamp the value to [0..255].

[Kevin Millikin (Chromium), 2011/05/16 07:06:35]

Can we remove this clamping?

[danno, 2011/05/16 14:13:43]

Done.

           Label done;
           __ testl(value, Immediate(0xFFFFFF00));
           __ j(zero, &done, Label::kNear);
           __ setcc(negative, value);  // 1 if negative, 0 if positive.
           __ decb(value);  // 0 if negative, 255 if positive.
           __ bind(&done);
           __ movb(operand, value);
         }
         break;
       case kExternalByteArray:
@@ skipping 579 matching lines @@
 void LCodeGen::DoCheckMap(LCheckMap* instr) {
   LOperand* input = instr->InputAt(0);
   ASSERT(input->IsRegister());
   Register reg = ToRegister(input);
   __ Cmp(FieldOperand(reg, HeapObject::kMapOffset),
          instr->hydrogen()->map());
   DeoptimizeIf(not_equal, instr->environment());
 }
 
 
+void LCodeGen::DoClampDoubleToUint8(LClampDoubleToUint8* instr) {
+  XMMRegister value_reg = ToDoubleRegister(instr->unclamped());
+  Register result_reg = ToRegister(instr->result());
+  Register temp_reg = ToRegister(instr->TempAt(0));
+  __ ClampDoubleToUint8(value_reg, xmm0, result_reg, temp_reg);
+}
+
+
+void LCodeGen::DoClampIToUint8(LClampIToUint8* instr) {
+  ASSERT(instr->unclamped()->Equals(instr->result()));
+  Register value_reg = ToRegister(instr->result());
+  __ ClampUint8(value_reg);
+}
+
+
+void LCodeGen::DoClampTaggedToUint8(LClampTaggedToUint8* instr) {
+  ASSERT(instr->unclamped()->Equals(instr->result()));
+  Register input_reg = ToRegister(instr->unclamped());
+  Register temp_reg = ToRegister(instr->TempAt(0));
+  XMMRegister temp_xmm_reg = ToDoubleRegister(instr->TempAt(1));
+  Label is_smi, done, heap_number;
+
+  __ JumpIfSmi(input_reg, &is_smi);
+
+  // Check for heap number
+  __ Cmp(FieldOperand(input_reg, HeapObject::kMapOffset),
+         factory()->heap_number_map());
+  __ j(equal, &heap_number, Label::kNear);
+
+  // Check for undefined. Undefined is converted to zero for clamping
+  // conversions.
+  __ Cmp(input_reg, factory()->undefined_value());
+  DeoptimizeIf(not_equal, instr->environment());
+  __ movq(input_reg, Immediate(0));
+  __ jmp(&done, Label::kNear);
+
+  // Heap number
+  __ bind(&heap_number);
+  __ movsd(xmm0, FieldOperand(input_reg, HeapNumber::kValueOffset));
+  __ ClampDoubleToUint8(xmm0, temp_xmm_reg, input_reg, temp_reg);
+  __ jmp(&done, Label::kNear);
+
+  // smi
+  __ bind(&is_smi);
+  __ SmiToInteger32(input_reg, input_reg);
+  __ ClampUint8(input_reg);
+
+  __ bind(&done);
+}
+
+
 void LCodeGen::LoadHeapObject(Register result, Handle<HeapObject> object) {
   if (heap()->InNewSpace(*object)) {
     Handle<JSGlobalPropertyCell> cell =
         factory()->NewJSGlobalPropertyCell(object);
     __ movq(result, cell, RelocInfo::GLOBAL_PROPERTY_CELL);
     __ movq(result, Operand(result, 0));
   } else {
     __ Move(result, object);
   }
 }
@@ skipping 397 matching lines @@
   RegisterEnvironmentForDeoptimization(environment);
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64