weex_core/Source/include/JavaScriptCore/assembler/MacroAssemblerX86.h - incubator-weex - Git at Google

 /**
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  */
 #pragma once

 #if ENABLE(ASSEMBLER) && CPU(X86)

 #include "MacroAssemblerX86Common.h"

 namespace JSC {

 class MacroAssemblerX86 : public MacroAssemblerX86Common {
 public:
     static const unsigned numGPRs = 8;
     static const unsigned numFPRs = 8;

     static const Scale ScalePtr = TimesFour;

     using MacroAssemblerX86Common::add32;
     using MacroAssemblerX86Common::and32;
     using MacroAssemblerX86Common::branchAdd32;
     using MacroAssemblerX86Common::branchSub32;
     using MacroAssemblerX86Common::sub32;
     using MacroAssemblerX86Common::or32;
     using MacroAssemblerX86Common::load32;
     using MacroAssemblerX86Common::load8;
     using MacroAssemblerX86Common::store32;
     using MacroAssemblerX86Common::store8;
     using MacroAssemblerX86Common::branch32;
     using MacroAssemblerX86Common::call;
     using MacroAssemblerX86Common::jump;
     using MacroAssemblerX86Common::addDouble;
     using MacroAssemblerX86Common::loadDouble;
     using MacroAssemblerX86Common::storeDouble;
     using MacroAssemblerX86Common::convertInt32ToDouble;
     using MacroAssemblerX86Common::branch8;
     using MacroAssemblerX86Common::branchTest8;

     void add32(TrustedImm32 imm, RegisterID src, RegisterID dest)
     {
         m_assembler.leal_mr(imm.m_value, src, dest);
     }

     void add32(TrustedImm32 imm, AbsoluteAddress address)
     {
         m_assembler.addl_im(imm.m_value, address.m_ptr);
     }

     void add32(AbsoluteAddress address, RegisterID dest)
     {
         m_assembler.addl_mr(address.m_ptr, dest);
     }

     void add64(TrustedImm32 imm, AbsoluteAddress address)
     {
         m_assembler.addl_im(imm.m_value, address.m_ptr);
         m_assembler.adcl_im(imm.m_value >> 31, reinterpret_cast<const char*>(address.m_ptr) + sizeof(int32_t));
     }

     void and32(TrustedImm32 imm, AbsoluteAddress address)
     {
         m_assembler.andl_im(imm.m_value, address.m_ptr);
     }

     void or32(TrustedImm32 imm, AbsoluteAddress address)
     {
         m_assembler.orl_im(imm.m_value, address.m_ptr);
     }

     void or32(RegisterID reg, AbsoluteAddress address)
     {
         m_assembler.orl_rm(reg, address.m_ptr);
     }

     void sub32(TrustedImm32 imm, AbsoluteAddress address)
     {
         m_assembler.subl_im(imm.m_value, address.m_ptr);
     }

     void load32(const void* address, RegisterID dest)
     {
         m_assembler.movl_mr(address, dest);
     }

     void load8(const void* address, RegisterID dest)
     {
         m_assembler.movzbl_mr(address, dest);
     }

     void abortWithReason(AbortReason reason)
     {
         move(TrustedImm32(reason), X86Registers::eax);
         breakpoint();
     }

     void abortWithReason(AbortReason reason, intptr_t misc)
     {
         move(TrustedImm32(misc), X86Registers::edx);
         abortWithReason(reason);
     }

     ConvertibleLoadLabel convertibleLoadPtr(Address address, RegisterID dest)
     {
         ConvertibleLoadLabel result = ConvertibleLoadLabel(this);
         m_assembler.movl_mr(address.offset, address.base, dest);
         return result;
     }

     void addDouble(AbsoluteAddress address, FPRegisterID dest)
     {
         m_assembler.addsd_mr(address.m_ptr, dest);
     }

     void storeDouble(FPRegisterID src, TrustedImmPtr address)
     {
         ASSERT(isSSE2Present());
         ASSERT(address.m_value);
         m_assembler.movsd_rm(src, address.m_value);
     }

     void convertInt32ToDouble(AbsoluteAddress src, FPRegisterID dest)
     {
         m_assembler.cvtsi2sd_mr(src.m_ptr, dest);
     }

     // this function should only be used in base line JIT.
     // Used in DFGJIT will cause xmm0 register clobbered.
     void store64Exclusive(RegisterID s0, RegisterID s1, TrustedImmPtr address)
     {
         push(s1);
         push(s0);
         move(address, s0);
         m_assembler.movq_mr(X86Registers::esp, X86Registers::xmm0);
         m_assembler.movq_rm(X86Registers::xmm0, s0);
         pop(s0);
         m_assembler.addl_ir(4, X86Registers::esp);
     }

     void store32(TrustedImm32 imm, void* address)
     {
         m_assembler.movl_i32m(imm.m_value, address);
     }

     void store32(RegisterID src, void* address)
     {
         m_assembler.movl_rm(src, address);
     }

     void store8(RegisterID src, void* address)
     {
         m_assembler.movb_rm(src, address);
     }

     void store8(TrustedImm32 imm, void* address)
     {
         TrustedImm32 imm8(static_cast<int8_t>(imm.m_value));
         m_assembler.movb_i8m(imm8.m_value, address);
     }

     void moveDoubleToInts(FPRegisterID src, RegisterID dest1, RegisterID dest2)
     {
         ASSERT(isSSE2Present());
         m_assembler.pextrw_irr(3, src, dest1);
         m_assembler.pextrw_irr(2, src, dest2);
         lshift32(TrustedImm32(16), dest1);
         or32(dest1, dest2);
         moveFloatTo32(src, dest1);
     }

     void moveIntsToDouble(RegisterID src1, RegisterID src2, FPRegisterID dest, FPRegisterID scratch)
     {
         move32ToFloat(src1, dest);
         move32ToFloat(src2, scratch);
         lshiftPacked(TrustedImm32(32), scratch);
         orPacked(scratch, dest);
     }

     Jump branchAdd32(ResultCondition cond, TrustedImm32 imm, AbsoluteAddress dest)
     {
         m_assembler.addl_im(imm.m_value, dest.m_ptr);
         return Jump(m_assembler.jCC(x86Condition(cond)));
     }

     Jump branchSub32(ResultCondition cond, TrustedImm32 imm, AbsoluteAddress dest)
     {
         m_assembler.subl_im(imm.m_value, dest.m_ptr);
         return Jump(m_assembler.jCC(x86Condition(cond)));
     }

     Jump branch32(RelationalCondition cond, AbsoluteAddress left, RegisterID right)
     {
         m_assembler.cmpl_rm(right, left.m_ptr);
         return Jump(m_assembler.jCC(x86Condition(cond)));
     }

     Jump branch32(RelationalCondition cond, AbsoluteAddress left, TrustedImm32 right)
     {
         m_assembler.cmpl_im(right.m_value, left.m_ptr);
         return Jump(m_assembler.jCC(x86Condition(cond)));
     }

     Call call()
     {
         return Call(m_assembler.call(), Call::Linkable);
     }

     // Address is a memory location containing the address to jump to
     void jump(AbsoluteAddress address)
     {
         m_assembler.jmp_m(address.m_ptr);
     }

     Call tailRecursiveCall()
     {
         return Call::fromTailJump(jump());
     }

     Call makeTailRecursiveCall(Jump oldJump)
     {
         return Call::fromTailJump(oldJump);
     }


     DataLabelPtr moveWithPatch(TrustedImmPtr initialValue, RegisterID dest)
     {
         padBeforePatch();
         m_assembler.movl_i32r(initialValue.asIntptr(), dest);
         return DataLabelPtr(this);
     }

     Jump branch8(RelationalCondition cond, AbsoluteAddress left, TrustedImm32 right)
     {
         TrustedImm32 right8(static_cast<int8_t>(right.m_value));
         m_assembler.cmpb_im(right8.m_value, left.m_ptr);
         return Jump(m_assembler.jCC(x86Condition(cond)));
     }

     Jump branchTest8(ResultCondition cond, AbsoluteAddress address, TrustedImm32 mask = TrustedImm32(-1))
     {
         TrustedImm32 mask8(static_cast<int8_t>(mask.m_value));
         if (mask8.m_value == -1)
             m_assembler.cmpb_im(0, address.m_ptr);
         else
             m_assembler.testb_im(mask8.m_value, address.m_ptr);
         return Jump(m_assembler.jCC(x86Condition(cond)));
     }

     Jump branchPtrWithPatch(RelationalCondition cond, RegisterID left, DataLabelPtr& dataLabel, TrustedImmPtr initialRightValue = TrustedImmPtr(0))
     {
         padBeforePatch();
         m_assembler.cmpl_ir_force32(initialRightValue.asIntptr(), left);
         dataLabel = DataLabelPtr(this);
         return Jump(m_assembler.jCC(x86Condition(cond)));
     }

     Jump branchPtrWithPatch(RelationalCondition cond, Address left, DataLabelPtr& dataLabel, TrustedImmPtr initialRightValue = TrustedImmPtr(0))
     {
         padBeforePatch();
         m_assembler.cmpl_im_force32(initialRightValue.asIntptr(), left.offset, left.base);
         dataLabel = DataLabelPtr(this);
         return Jump(m_assembler.jCC(x86Condition(cond)));
     }

     Jump branch32WithPatch(RelationalCondition cond, Address left, DataLabel32& dataLabel, TrustedImm32 initialRightValue = TrustedImm32(0))
     {
         padBeforePatch();
         m_assembler.cmpl_im_force32(initialRightValue.m_value, left.offset, left.base);
         dataLabel = DataLabel32(this);
         return Jump(m_assembler.jCC(x86Condition(cond)));
     }

     DataLabelPtr storePtrWithPatch(TrustedImmPtr initialValue, ImplicitAddress address)
     {
         padBeforePatch();
         m_assembler.movl_i32m(initialValue.asIntptr(), address.offset, address.base);
         return DataLabelPtr(this);
     }

     static bool supportsFloatingPoint() { return isSSE2Present(); }
     static bool supportsFloatingPointTruncate() { return isSSE2Present(); }
     static bool supportsFloatingPointSqrt() { return isSSE2Present(); }
     static bool supportsFloatingPointAbs() { return isSSE2Present(); }

     static FunctionPtr readCallTarget(CodeLocationCall call)
     {
         intptr_t offset = reinterpret_cast<int32_t*>(call.dataLocation())[-1];
         return FunctionPtr(reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(call.dataLocation()) + offset));
     }

     static bool canJumpReplacePatchableBranchPtrWithPatch() { return true; }
     static bool canJumpReplacePatchableBranch32WithPatch() { return true; }

     static CodeLocationLabel startOfBranchPtrWithPatchOnRegister(CodeLocationDataLabelPtr label)
     {
         const int opcodeBytes = 1;
         const int modRMBytes = 1;
         const int immediateBytes = 4;
         const int totalBytes = opcodeBytes + modRMBytes + immediateBytes;
         ASSERT(totalBytes >= maxJumpReplacementSize());
         return label.labelAtOffset(-totalBytes);
     }

     static CodeLocationLabel startOfPatchableBranchPtrWithPatchOnAddress(CodeLocationDataLabelPtr label)
     {
         const int opcodeBytes = 1;
         const int modRMBytes = 1;
         const int offsetBytes = 0;
         const int immediateBytes = 4;
         const int totalBytes = opcodeBytes + modRMBytes + offsetBytes + immediateBytes;
         ASSERT(totalBytes >= maxJumpReplacementSize());
         return label.labelAtOffset(-totalBytes);
     }

     static CodeLocationLabel startOfPatchableBranch32WithPatchOnAddress(CodeLocationDataLabel32 label)
     {
         const int opcodeBytes = 1;
         const int modRMBytes = 1;
         const int offsetBytes = 0;
         const int immediateBytes = 4;
         const int totalBytes = opcodeBytes + modRMBytes + offsetBytes + immediateBytes;
         ASSERT(totalBytes >= maxJumpReplacementSize());
         return label.labelAtOffset(-totalBytes);
     }

     static void revertJumpReplacementToBranchPtrWithPatch(CodeLocationLabel instructionStart, RegisterID reg, void* initialValue)
     {
         X86Assembler::revertJumpTo_cmpl_ir_force32(instructionStart.executableAddress(), reinterpret_cast<intptr_t>(initialValue), reg);
     }

     static void revertJumpReplacementToPatchableBranchPtrWithPatch(CodeLocationLabel instructionStart, Address address, void* initialValue)
     {
         ASSERT(!address.offset);
         X86Assembler::revertJumpTo_cmpl_im_force32(instructionStart.executableAddress(), reinterpret_cast<intptr_t>(initialValue), 0, address.base);
     }

     static void revertJumpReplacementToPatchableBranch32WithPatch(CodeLocationLabel instructionStart, Address address, int32_t initialValue)
     {
         ASSERT(!address.offset);
         X86Assembler::revertJumpTo_cmpl_im_force32(instructionStart.executableAddress(), initialValue, 0, address.base);
     }

     static void repatchCall(CodeLocationCall call, CodeLocationLabel destination)
     {
         X86Assembler::relinkCall(call.dataLocation(), destination.executableAddress());
     }

     static void repatchCall(CodeLocationCall call, FunctionPtr destination)
     {
         X86Assembler::relinkCall(call.dataLocation(), destination.executableAddress());
     }

 private:
     friend class LinkBuffer;

     static void linkCall(void* code, Call call, FunctionPtr function)
     {
         if (call.isFlagSet(Call::Tail))
             X86Assembler::linkJump(code, call.m_label, function.value());
         else
             X86Assembler::linkCall(code, call.m_label, function.value());
     }
 };

 } // namespace JSC

 #endif // ENABLE(ASSEMBLER)
	/**
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	*/
	#pragma once

	#if ENABLE(ASSEMBLER) && CPU(X86)

	#include "MacroAssemblerX86Common.h"

	namespace JSC {

	class MacroAssemblerX86 : public MacroAssemblerX86Common {
	public:
	static const unsigned numGPRs = 8;
	static const unsigned numFPRs = 8;

	static const Scale ScalePtr = TimesFour;

	using MacroAssemblerX86Common::add32;
	using MacroAssemblerX86Common::and32;
	using MacroAssemblerX86Common::branchAdd32;
	using MacroAssemblerX86Common::branchSub32;
	using MacroAssemblerX86Common::sub32;
	using MacroAssemblerX86Common::or32;
	using MacroAssemblerX86Common::load32;
	using MacroAssemblerX86Common::load8;
	using MacroAssemblerX86Common::store32;
	using MacroAssemblerX86Common::store8;
	using MacroAssemblerX86Common::branch32;
	using MacroAssemblerX86Common::call;
	using MacroAssemblerX86Common::jump;
	using MacroAssemblerX86Common::addDouble;
	using MacroAssemblerX86Common::loadDouble;
	using MacroAssemblerX86Common::storeDouble;
	using MacroAssemblerX86Common::convertInt32ToDouble;
	using MacroAssemblerX86Common::branch8;
	using MacroAssemblerX86Common::branchTest8;

	void add32(TrustedImm32 imm, RegisterID src, RegisterID dest)
	{
	m_assembler.leal_mr(imm.m_value, src, dest);
	}

	void add32(TrustedImm32 imm, AbsoluteAddress address)
	{
	m_assembler.addl_im(imm.m_value, address.m_ptr);
	}

	void add32(AbsoluteAddress address, RegisterID dest)
	{
	m_assembler.addl_mr(address.m_ptr, dest);
	}

	void add64(TrustedImm32 imm, AbsoluteAddress address)
	{
	m_assembler.addl_im(imm.m_value, address.m_ptr);
	m_assembler.adcl_im(imm.m_value >> 31, reinterpret_cast<const char*>(address.m_ptr) + sizeof(int32_t));
	}

	void and32(TrustedImm32 imm, AbsoluteAddress address)
	{
	m_assembler.andl_im(imm.m_value, address.m_ptr);
	}

	void or32(TrustedImm32 imm, AbsoluteAddress address)
	{
	m_assembler.orl_im(imm.m_value, address.m_ptr);
	}

	void or32(RegisterID reg, AbsoluteAddress address)
	{
	m_assembler.orl_rm(reg, address.m_ptr);
	}

	void sub32(TrustedImm32 imm, AbsoluteAddress address)
	{
	m_assembler.subl_im(imm.m_value, address.m_ptr);
	}

	void load32(const void* address, RegisterID dest)
	{
	m_assembler.movl_mr(address, dest);
	}

	void load8(const void* address, RegisterID dest)
	{
	m_assembler.movzbl_mr(address, dest);
	}

	void abortWithReason(AbortReason reason)
	{
	move(TrustedImm32(reason), X86Registers::eax);
	breakpoint();
	}

	void abortWithReason(AbortReason reason, intptr_t misc)
	{
	move(TrustedImm32(misc), X86Registers::edx);
	abortWithReason(reason);
	}

	ConvertibleLoadLabel convertibleLoadPtr(Address address, RegisterID dest)
	{
	ConvertibleLoadLabel result = ConvertibleLoadLabel(this);
	m_assembler.movl_mr(address.offset, address.base, dest);
	return result;
	}

	void addDouble(AbsoluteAddress address, FPRegisterID dest)
	{
	m_assembler.addsd_mr(address.m_ptr, dest);
	}

	void storeDouble(FPRegisterID src, TrustedImmPtr address)
	{
	ASSERT(isSSE2Present());
	ASSERT(address.m_value);
	m_assembler.movsd_rm(src, address.m_value);
	}

	void convertInt32ToDouble(AbsoluteAddress src, FPRegisterID dest)
	{
	m_assembler.cvtsi2sd_mr(src.m_ptr, dest);
	}

	// this function should only be used in base line JIT.
	// Used in DFGJIT will cause xmm0 register clobbered.
	void store64Exclusive(RegisterID s0, RegisterID s1, TrustedImmPtr address)
	{
	push(s1);
	push(s0);
	move(address, s0);
	m_assembler.movq_mr(X86Registers::esp, X86Registers::xmm0);
	m_assembler.movq_rm(X86Registers::xmm0, s0);
	pop(s0);
	m_assembler.addl_ir(4, X86Registers::esp);
	}

	void store32(TrustedImm32 imm, void* address)
	{
	m_assembler.movl_i32m(imm.m_value, address);
	}

	void store32(RegisterID src, void* address)
	{
	m_assembler.movl_rm(src, address);
	}

	void store8(RegisterID src, void* address)
	{
	m_assembler.movb_rm(src, address);
	}

	void store8(TrustedImm32 imm, void* address)
	{
	TrustedImm32 imm8(static_cast<int8_t>(imm.m_value));
	m_assembler.movb_i8m(imm8.m_value, address);
	}

	void moveDoubleToInts(FPRegisterID src, RegisterID dest1, RegisterID dest2)
	{
	ASSERT(isSSE2Present());
	m_assembler.pextrw_irr(3, src, dest1);
	m_assembler.pextrw_irr(2, src, dest2);
	lshift32(TrustedImm32(16), dest1);
	or32(dest1, dest2);
	moveFloatTo32(src, dest1);
	}

	void moveIntsToDouble(RegisterID src1, RegisterID src2, FPRegisterID dest, FPRegisterID scratch)
	{
	move32ToFloat(src1, dest);
	move32ToFloat(src2, scratch);
	lshiftPacked(TrustedImm32(32), scratch);
	orPacked(scratch, dest);
	}

	Jump branchAdd32(ResultCondition cond, TrustedImm32 imm, AbsoluteAddress dest)
	{
	m_assembler.addl_im(imm.m_value, dest.m_ptr);
	return Jump(m_assembler.jCC(x86Condition(cond)));
	}

	Jump branchSub32(ResultCondition cond, TrustedImm32 imm, AbsoluteAddress dest)
	{
	m_assembler.subl_im(imm.m_value, dest.m_ptr);
	return Jump(m_assembler.jCC(x86Condition(cond)));
	}

	Jump branch32(RelationalCondition cond, AbsoluteAddress left, RegisterID right)
	{
	m_assembler.cmpl_rm(right, left.m_ptr);
	return Jump(m_assembler.jCC(x86Condition(cond)));
	}

	Jump branch32(RelationalCondition cond, AbsoluteAddress left, TrustedImm32 right)
	{
	m_assembler.cmpl_im(right.m_value, left.m_ptr);
	return Jump(m_assembler.jCC(x86Condition(cond)));
	}

	Call call()
	{
	return Call(m_assembler.call(), Call::Linkable);
	}

	// Address is a memory location containing the address to jump to
	void jump(AbsoluteAddress address)
	{
	m_assembler.jmp_m(address.m_ptr);
	}

	Call tailRecursiveCall()
	{
	return Call::fromTailJump(jump());
	}

	Call makeTailRecursiveCall(Jump oldJump)
	{
	return Call::fromTailJump(oldJump);
	}


	DataLabelPtr moveWithPatch(TrustedImmPtr initialValue, RegisterID dest)
	{
	padBeforePatch();
	m_assembler.movl_i32r(initialValue.asIntptr(), dest);
	return DataLabelPtr(this);
	}

	Jump branch8(RelationalCondition cond, AbsoluteAddress left, TrustedImm32 right)
	{
	TrustedImm32 right8(static_cast<int8_t>(right.m_value));
	m_assembler.cmpb_im(right8.m_value, left.m_ptr);
	return Jump(m_assembler.jCC(x86Condition(cond)));
	}

	Jump branchTest8(ResultCondition cond, AbsoluteAddress address, TrustedImm32 mask = TrustedImm32(-1))
	{
	TrustedImm32 mask8(static_cast<int8_t>(mask.m_value));
	if (mask8.m_value == -1)
	m_assembler.cmpb_im(0, address.m_ptr);
	else
	m_assembler.testb_im(mask8.m_value, address.m_ptr);
	return Jump(m_assembler.jCC(x86Condition(cond)));
	}

	Jump branchPtrWithPatch(RelationalCondition cond, RegisterID left, DataLabelPtr& dataLabel, TrustedImmPtr initialRightValue = TrustedImmPtr(0))
	{
	padBeforePatch();
	m_assembler.cmpl_ir_force32(initialRightValue.asIntptr(), left);
	dataLabel = DataLabelPtr(this);
	return Jump(m_assembler.jCC(x86Condition(cond)));
	}

	Jump branchPtrWithPatch(RelationalCondition cond, Address left, DataLabelPtr& dataLabel, TrustedImmPtr initialRightValue = TrustedImmPtr(0))
	{
	padBeforePatch();
	m_assembler.cmpl_im_force32(initialRightValue.asIntptr(), left.offset, left.base);
	dataLabel = DataLabelPtr(this);
	return Jump(m_assembler.jCC(x86Condition(cond)));
	}

	Jump branch32WithPatch(RelationalCondition cond, Address left, DataLabel32& dataLabel, TrustedImm32 initialRightValue = TrustedImm32(0))
	{
	padBeforePatch();
	m_assembler.cmpl_im_force32(initialRightValue.m_value, left.offset, left.base);
	dataLabel = DataLabel32(this);
	return Jump(m_assembler.jCC(x86Condition(cond)));
	}

	DataLabelPtr storePtrWithPatch(TrustedImmPtr initialValue, ImplicitAddress address)
	{
	padBeforePatch();
	m_assembler.movl_i32m(initialValue.asIntptr(), address.offset, address.base);
	return DataLabelPtr(this);
	}

	static bool supportsFloatingPoint() { return isSSE2Present(); }
	static bool supportsFloatingPointTruncate() { return isSSE2Present(); }
	static bool supportsFloatingPointSqrt() { return isSSE2Present(); }
	static bool supportsFloatingPointAbs() { return isSSE2Present(); }

	static FunctionPtr readCallTarget(CodeLocationCall call)
	{
	intptr_t offset = reinterpret_cast<int32_t*>(call.dataLocation())[-1];
	return FunctionPtr(reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(call.dataLocation()) + offset));
	}

	static bool canJumpReplacePatchableBranchPtrWithPatch() { return true; }
	static bool canJumpReplacePatchableBranch32WithPatch() { return true; }

	static CodeLocationLabel startOfBranchPtrWithPatchOnRegister(CodeLocationDataLabelPtr label)
	{
	const int opcodeBytes = 1;
	const int modRMBytes = 1;
	const int immediateBytes = 4;
	const int totalBytes = opcodeBytes + modRMBytes + immediateBytes;
	ASSERT(totalBytes >= maxJumpReplacementSize());
	return label.labelAtOffset(-totalBytes);
	}

	static CodeLocationLabel startOfPatchableBranchPtrWithPatchOnAddress(CodeLocationDataLabelPtr label)
	{
	const int opcodeBytes = 1;
	const int modRMBytes = 1;
	const int offsetBytes = 0;
	const int immediateBytes = 4;
	const int totalBytes = opcodeBytes + modRMBytes + offsetBytes + immediateBytes;
	ASSERT(totalBytes >= maxJumpReplacementSize());
	return label.labelAtOffset(-totalBytes);
	}

	static CodeLocationLabel startOfPatchableBranch32WithPatchOnAddress(CodeLocationDataLabel32 label)
	{
	const int opcodeBytes = 1;
	const int modRMBytes = 1;
	const int offsetBytes = 0;
	const int immediateBytes = 4;
	const int totalBytes = opcodeBytes + modRMBytes + offsetBytes + immediateBytes;
	ASSERT(totalBytes >= maxJumpReplacementSize());
	return label.labelAtOffset(-totalBytes);
	}

	static void revertJumpReplacementToBranchPtrWithPatch(CodeLocationLabel instructionStart, RegisterID reg, void* initialValue)
	{
	X86Assembler::revertJumpTo_cmpl_ir_force32(instructionStart.executableAddress(), reinterpret_cast<intptr_t>(initialValue), reg);
	}

	static void revertJumpReplacementToPatchableBranchPtrWithPatch(CodeLocationLabel instructionStart, Address address, void* initialValue)
	{
	ASSERT(!address.offset);
	X86Assembler::revertJumpTo_cmpl_im_force32(instructionStart.executableAddress(), reinterpret_cast<intptr_t>(initialValue), 0, address.base);
	}

	static void revertJumpReplacementToPatchableBranch32WithPatch(CodeLocationLabel instructionStart, Address address, int32_t initialValue)
	{
	ASSERT(!address.offset);
	X86Assembler::revertJumpTo_cmpl_im_force32(instructionStart.executableAddress(), initialValue, 0, address.base);
	}

	static void repatchCall(CodeLocationCall call, CodeLocationLabel destination)
	{
	X86Assembler::relinkCall(call.dataLocation(), destination.executableAddress());
	}

	static void repatchCall(CodeLocationCall call, FunctionPtr destination)
	{
	X86Assembler::relinkCall(call.dataLocation(), destination.executableAddress());
	}

	private:
	friend class LinkBuffer;

	static void linkCall(void* code, Call call, FunctionPtr function)
	{
	if (call.isFlagSet(Call::Tail))
	X86Assembler::linkJump(code, call.m_label, function.value());
	else
	X86Assembler::linkCall(code, call.m_label, function.value());
	}
	};

	} // namespace JSC

	#endif // ENABLE(ASSEMBLER)