runtime/vm/instructions_arm.cc - sdk.git - Git at Google

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.

 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_ARM.
 #if defined(TARGET_ARCH_ARM)

 #include "vm/assembler.h"
 #include "vm/constants_arm.h"
 #include "vm/cpu.h"
 #include "vm/instructions.h"
 #include "vm/object.h"

 namespace dart {

 CallPattern::CallPattern(uword pc, const Code& code)
     : object_pool_(Array::Handle(code.ObjectPool())),
       end_(pc),
       args_desc_load_end_(0),
       ic_data_load_end_(0),
       target_address_pool_index_(-1),
       args_desc_(Array::Handle()),
       ic_data_(ICData::Handle()) {
   ASSERT(code.ContainsInstructionAt(pc));
   // Last instruction: blx lr.
   ASSERT(*(reinterpret_cast<uword*>(end_) - 1) == 0xe12fff3e);

   Register reg;
   ic_data_load_end_ =
       InstructionPattern::DecodeLoadWordFromPool(end_ - Instr::kInstrSize,
                                                  &reg,
                                                  &target_address_pool_index_);
   ASSERT(reg == LR);
 }


 int CallPattern::LengthInBytes() {
   const ARMVersion version = TargetCPUFeatures::arm_version();
   if ((version == ARMv5TE) || (version == ARMv6)) {
     return 5 * Instr::kInstrSize;
   } else {
     ASSERT(version == ARMv7);
     return 3 * Instr::kInstrSize;
   }
 }


 // Decodes a load sequence ending at 'end' (the last instruction of the load
 // sequence is the instruction before the one at end).  Returns a pointer to
 // the first instruction in the sequence.  Returns the register being loaded
 // and the loaded object in the output parameters 'reg' and 'obj'
 // respectively.
 uword InstructionPattern::DecodeLoadObject(uword end,
                                            const Array& object_pool,
                                            Register* reg,
                                            Object* obj) {
   uword start = 0;
   Instr* instr = Instr::At(end - Instr::kInstrSize);
   if ((instr->InstructionBits() & 0xfff00000) == 0xe5900000) {
     // ldr reg, [reg, #+offset]
     intptr_t index = 0;
     start = DecodeLoadWordFromPool(end, reg, &index);
     *obj = object_pool.At(index);
   } else {
     intptr_t value = 0;
     start = DecodeLoadWordImmediate(end, reg, &value);
     *obj = reinterpret_cast<RawObject*>(value);
   }
   return start;
 }


 // Decodes a load sequence ending at 'end' (the last instruction of the load
 // sequence is the instruction before the one at end).  Returns a pointer to
 // the first instruction in the sequence.  Returns the register being loaded
 // and the loaded immediate value in the output parameters 'reg' and 'value'
 // respectively.
 uword InstructionPattern::DecodeLoadWordImmediate(uword end,
                                                   Register* reg,
                                                   intptr_t* value) {
   uword start = end - Instr::kInstrSize;
   int32_t instr = Instr::At(start)->InstructionBits();
   intptr_t imm = 0;
   const ARMVersion version = TargetCPUFeatures::arm_version();
   if ((version == ARMv5TE) || (version == ARMv6)) {
     ASSERT((instr & 0xfff00000) == 0xe3800000);  // orr rd, rd, byte0
     imm |= (instr & 0x000000ff);

     start -= Instr::kInstrSize;
     instr = Instr::At(start)->InstructionBits();
     ASSERT((instr & 0xfff00000) == 0xe3800c00);  // orr rd, rd, (byte1 rot 12)
     imm |= (instr & 0x000000ff);

     start -= Instr::kInstrSize;
     instr = Instr::At(start)->InstructionBits();
     ASSERT((instr & 0xfff00f00) == 0xe3800800);  // orr rd, rd, (byte2 rot 8)
     imm |= (instr & 0x000000ff);

     start -= Instr::kInstrSize;
     instr = Instr::At(start)->InstructionBits();
     ASSERT((instr & 0xffff0f00) == 0xe3a00400);  // mov rd, (byte3 rot 4)
     imm |= (instr & 0x000000ff);

     *reg = static_cast<Register>((instr & 0x0000f000) >> 12);
     *value = imm;
   } else {
     ASSERT(version == ARMv7);
     if ((instr & 0xfff00000) == 0xe3400000) {  // movt reg, #imm_hi
       imm |= (instr & 0xf0000) << 12;
       imm |= (instr & 0xfff) << 16;
       start -= Instr::kInstrSize;
       instr = Instr::At(start)->InstructionBits();
     }
     ASSERT((instr & 0xfff00000) == 0xe3000000);  // movw reg, #imm_lo
     imm |= (instr & 0xf0000) >> 4;
     imm |= instr & 0xfff;
     *reg = static_cast<Register>((instr & 0xf000) >> 12);
     *value = imm;
   }
   return start;
 }


 // Decodes a load sequence ending at 'end' (the last instruction of the load
 // sequence is the instruction before the one at end).  Returns a pointer to
 // the first instruction in the sequence.  Returns the register being loaded
 // and the index in the pool being read from in the output parameters 'reg'
 // and 'index' respectively.
 uword InstructionPattern::DecodeLoadWordFromPool(uword end,
                                                  Register* reg,
                                                  intptr_t* index) {
   uword start = end - Instr::kInstrSize;
   int32_t instr = Instr::At(start)->InstructionBits();
   intptr_t offset = 0;
   if ((instr & 0xffff0000) == 0xe59a0000) {  // ldr reg, [pp, #+offset]
     offset = instr & 0xfff;
     *reg = static_cast<Register>((instr & 0xf000) >> 12);
   } else {
     ASSERT((instr & 0xfff00000) == 0xe5900000);  // ldr reg, [reg, #+offset]
     offset = instr & 0xfff;
     start -= Instr::kInstrSize;
     instr = Instr::At(start)->InstructionBits();
     if ((instr & 0xffff0000) == 0xe28a0000) {  // add reg, pp, operand
       const intptr_t rot = (instr & 0xf00) >> 7;
       const intptr_t imm8 = instr & 0xff;
       offset += (imm8 >> rot) | (imm8 << (32 - rot));
       *reg = static_cast<Register>((instr & 0xf000) >> 12);
     } else {
       ASSERT((instr & 0xffff0000) == 0xe08a0000);  // add reg, pp, reg
       end = DecodeLoadWordImmediate(end, reg, &offset);
     }
   }
   offset += kHeapObjectTag;
   ASSERT(Utils::IsAligned(offset, 4));
   *index = (offset - Array::data_offset()) / 4;
   return start;
 }


 RawICData* CallPattern::IcData() {
   if (ic_data_.IsNull()) {
     Register reg;
     args_desc_load_end_ =
         InstructionPattern::DecodeLoadObject(ic_data_load_end_,
                                              object_pool_,
                                              &reg,
                                              &ic_data_);
     ASSERT(reg == R5);
   }
   return ic_data_.raw();
 }


 RawArray* CallPattern::ClosureArgumentsDescriptor() {
   if (args_desc_.IsNull()) {
     IcData();  // Loading of the ic_data must be decoded first, if not already.
     Register reg;
     InstructionPattern::DecodeLoadObject(args_desc_load_end_,
                                          object_pool_,
                                          &reg,
                                          &args_desc_);
     ASSERT(reg == R4);
   }
   return args_desc_.raw();
 }


 uword CallPattern::TargetAddress() const {
   ASSERT(target_address_pool_index_ >= 0);
   const Object& target_address =
       Object::Handle(object_pool_.At(target_address_pool_index_));
   ASSERT(target_address.IsSmi());
   // The address is stored in the object array as a RawSmi.
   return reinterpret_cast<uword>(target_address.raw());
 }


 void CallPattern::SetTargetAddress(uword target_address) const {
   ASSERT(Utils::IsAligned(target_address, 4));
   // The address is stored in the object array as a RawSmi.
   const Smi& smi = Smi::Handle(reinterpret_cast<RawSmi*>(target_address));
   object_pool_.SetAt(target_address_pool_index_, smi);
   // No need to flush the instruction cache, since the code is not modified.
 }


 void CallPattern::InsertAt(uword pc, uword target_address) {
   const ARMVersion version = TargetCPUFeatures::arm_version();
   if ((version == ARMv5TE) || (version == ARMv6)) {
     const uint32_t byte0 = (target_address & 0x000000ff);
     const uint32_t byte1 = (target_address & 0x0000ff00) >> 8;
     const uint32_t byte2 = (target_address & 0x00ff0000) >> 16;
     const uint32_t byte3 = (target_address & 0xff000000) >> 24;

     const uword mov_ip = 0xe3a0c400 | byte3;  // mov ip, (byte3 rot 4)
     const uword or1_ip = 0xe38cc800 | byte2;  // orr ip, ip, (byte2 rot 8)
     const uword or2_ip = 0xe38ccc00 | byte1;  // orr ip, ip, (byte1 rot 12)
     const uword or3_ip = 0xe38cc000 | byte0;  // orr ip, ip, byte0
     const uword blx_ip = 0xe12fff3c;

     *reinterpret_cast<uword*>(pc + (0 * Instr::kInstrSize)) = mov_ip;
     *reinterpret_cast<uword*>(pc + (1 * Instr::kInstrSize)) = or1_ip;
     *reinterpret_cast<uword*>(pc + (2 * Instr::kInstrSize)) = or2_ip;
     *reinterpret_cast<uword*>(pc + (3 * Instr::kInstrSize)) = or3_ip;
     *reinterpret_cast<uword*>(pc + (4 * Instr::kInstrSize)) = blx_ip;

     ASSERT(LengthInBytes() == 5 * Instr::kInstrSize);
     CPU::FlushICache(pc, LengthInBytes());
   } else {
     ASSERT(version == ARMv7);
     const uint16_t target_lo = target_address & 0xffff;
     const uint16_t target_hi = target_address >> 16;

     const uword movw_ip =
         0xe300c000 | ((target_lo >> 12) << 16) | (target_lo & 0xfff);
     const uword movt_ip =
         0xe340c000 | ((target_hi >> 12) << 16) | (target_hi & 0xfff);
     const uword blx_ip = 0xe12fff3c;

     *reinterpret_cast<uword*>(pc + (0 * Instr::kInstrSize)) = movw_ip;
     *reinterpret_cast<uword*>(pc + (1 * Instr::kInstrSize)) = movt_ip;
     *reinterpret_cast<uword*>(pc + (2 * Instr::kInstrSize)) = blx_ip;

     ASSERT(LengthInBytes() == 3 * Instr::kInstrSize);
     CPU::FlushICache(pc, LengthInBytes());
   }
 }


 JumpPattern::JumpPattern(uword pc, const Code& code) : pc_(pc) { }


 int JumpPattern::pattern_length_in_bytes() {
   const ARMVersion version = TargetCPUFeatures::arm_version();
   if ((version == ARMv5TE) || (version == ARMv6)) {
     return 5 * Instr::kInstrSize;
   } else {
     ASSERT(version == ARMv7);
     return 3 * Instr::kInstrSize;
   }
 }


 bool JumpPattern::IsValid() const {
   const ARMVersion version = TargetCPUFeatures::arm_version();
   if ((version == ARMv5TE) || (version == ARMv6)) {
     Instr* mov_ip = Instr::At(pc_ + (0 * Instr::kInstrSize));
     Instr* or1_ip = Instr::At(pc_ + (1 * Instr::kInstrSize));
     Instr* or2_ip = Instr::At(pc_ + (2 * Instr::kInstrSize));
     Instr* or3_ip = Instr::At(pc_ + (3 * Instr::kInstrSize));
     Instr* bx_ip = Instr::At(pc_ + (4 * Instr::kInstrSize));
     return ((mov_ip->InstructionBits() & 0xffffff00) == 0xe3a0c400) &&
            ((or1_ip->InstructionBits() & 0xffffff00) == 0xe38cc800) &&
            ((or2_ip->InstructionBits() & 0xffffff00) == 0xe38ccc00) &&
            ((or3_ip->InstructionBits() & 0xffffff00) == 0xe38cc000) &&
            ((bx_ip->InstructionBits() & 0xffffffff) == 0xe12fff1c);
   } else {
     ASSERT(version == ARMv7);
     Instr* movw_ip = Instr::At(pc_ + (0 * Instr::kInstrSize));  // target_lo
     Instr* movt_ip = Instr::At(pc_ + (1 * Instr::kInstrSize));  // target_hi
     Instr* bx_ip = Instr::At(pc_ + (2 * Instr::kInstrSize));
     return (movw_ip->InstructionBits() & 0xfff0f000) == 0xe300c000 &&
            (movt_ip->InstructionBits() & 0xfff0f000) == 0xe340c000 &&
            (bx_ip->InstructionBits() & 0xffffffff) == 0xe12fff1c;
   }
 }


 uword JumpPattern::TargetAddress() const {
   const ARMVersion version = TargetCPUFeatures::arm_version();
   if ((version == ARMv5TE) || (version == ARMv6)) {
     Instr* mov_ip = Instr::At(pc_ + (0 * Instr::kInstrSize));
     Instr* or1_ip = Instr::At(pc_ + (1 * Instr::kInstrSize));
     Instr* or2_ip = Instr::At(pc_ + (2 * Instr::kInstrSize));
     Instr* or3_ip = Instr::At(pc_ + (3 * Instr::kInstrSize));
     uword imm = 0;
     imm |= or3_ip->Immed8Field();
     imm |= or2_ip->Immed8Field() << 8;
     imm |= or1_ip->Immed8Field() << 16;
     imm |= mov_ip->Immed8Field() << 24;
     return imm;
   } else {
     ASSERT(version == ARMv7);
     Instr* movw_ip = Instr::At(pc_ + (0 * Instr::kInstrSize));  // target_lo
     Instr* movt_ip = Instr::At(pc_ + (1 * Instr::kInstrSize));  // target_hi
     uint16_t target_lo = movw_ip->MovwField();
     uint16_t target_hi = movt_ip->MovwField();
     return (target_hi << 16) | target_lo;
   }
 }


 void JumpPattern::SetTargetAddress(uword target_address) const {
   const ARMVersion version = TargetCPUFeatures::arm_version();
   if ((version == ARMv5TE) || (version == ARMv6)) {
     const uint32_t byte0 = (target_address & 0x000000ff);
     const uint32_t byte1 = (target_address & 0x0000ff00) >> 8;
     const uint32_t byte2 = (target_address & 0x00ff0000) >> 16;
     const uint32_t byte3 = (target_address & 0xff000000) >> 24;

     const uword mov_ip = 0xe3a0c400 | byte3;  // mov ip, (byte3 rot 4)
     const uword or1_ip = 0xe38cc800 | byte2;  // orr ip, ip, (byte2 rot 8)
     const uword or2_ip = 0xe38ccc00 | byte1;  // orr ip, ip, (byte1 rot 12)
     const uword or3_ip = 0xe38cc000 | byte0;  // orr ip, ip, byte0

     *reinterpret_cast<uword*>(pc_ + (0 * Instr::kInstrSize)) = mov_ip;
     *reinterpret_cast<uword*>(pc_ + (1 * Instr::kInstrSize)) = or1_ip;
     *reinterpret_cast<uword*>(pc_ + (2 * Instr::kInstrSize)) = or2_ip;
     *reinterpret_cast<uword*>(pc_ + (3 * Instr::kInstrSize)) = or3_ip;
     CPU::FlushICache(pc_, 4 * Instr::kInstrSize);
   } else {
     ASSERT(version == ARMv7);
     const uint16_t target_lo = target_address & 0xffff;
     const uint16_t target_hi = target_address >> 16;

     const uword movw_ip =
         0xe300c000 | ((target_lo >> 12) << 16) | (target_lo & 0xfff);
     const uword movt_ip =
         0xe340c000 | ((target_hi >> 12) << 16) | (target_hi & 0xfff);

     *reinterpret_cast<uword*>(pc_ + (0 * Instr::kInstrSize)) = movw_ip;
     *reinterpret_cast<uword*>(pc_ + (1 * Instr::kInstrSize)) = movt_ip;
     CPU::FlushICache(pc_, 2 * Instr::kInstrSize);
   }
 }

 }  // namespace dart

 #endif  // defined TARGET_ARCH_ARM
	// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
	// for details. All rights reserved. Use of this source code is governed by a
	// BSD-style license that can be found in the LICENSE file.

	#include "vm/globals.h" // Needed here to get TARGET_ARCH_ARM.
	#if defined(TARGET_ARCH_ARM)

	#include "vm/assembler.h"
	#include "vm/constants_arm.h"
	#include "vm/cpu.h"
	#include "vm/instructions.h"
	#include "vm/object.h"

	namespace dart {

	CallPattern::CallPattern(uword pc, const Code& code)
	: object_pool_(Array::Handle(code.ObjectPool())),
	end_(pc),
	args_desc_load_end_(0),
	ic_data_load_end_(0),
	target_address_pool_index_(-1),
	args_desc_(Array::Handle()),
	ic_data_(ICData::Handle()) {
	ASSERT(code.ContainsInstructionAt(pc));
	// Last instruction: blx lr.
	ASSERT((reinterpret_cast<uword>(end_) - 1) == 0xe12fff3e);

	Register reg;
	ic_data_load_end_ =
	InstructionPattern::DecodeLoadWordFromPool(end_ - Instr::kInstrSize,
	&reg,
	&target_address_pool_index_);
	ASSERT(reg == LR);
	}


	int CallPattern::LengthInBytes() {
	const ARMVersion version = TargetCPUFeatures::arm_version();
	if ((version == ARMv5TE) \|\| (version == ARMv6)) {
	return 5 * Instr::kInstrSize;
	} else {
	ASSERT(version == ARMv7);
	return 3 * Instr::kInstrSize;
	}
	}


	// Decodes a load sequence ending at 'end' (the last instruction of the load
	// sequence is the instruction before the one at end). Returns a pointer to
	// the first instruction in the sequence. Returns the register being loaded
	// and the loaded object in the output parameters 'reg' and 'obj'
	// respectively.
	uword InstructionPattern::DecodeLoadObject(uword end,
	const Array& object_pool,
	Register* reg,
	Object* obj) {
	uword start = 0;
	Instr* instr = Instr::At(end - Instr::kInstrSize);
	if ((instr->InstructionBits() & 0xfff00000) == 0xe5900000) {
	// ldr reg, [reg, #+offset]
	intptr_t index = 0;
	start = DecodeLoadWordFromPool(end, reg, &index);
	*obj = object_pool.At(index);
	} else {
	intptr_t value = 0;
	start = DecodeLoadWordImmediate(end, reg, &value);
	obj = reinterpret_cast<RawObject>(value);
	}
	return start;
	}


	// Decodes a load sequence ending at 'end' (the last instruction of the load
	// sequence is the instruction before the one at end). Returns a pointer to
	// the first instruction in the sequence. Returns the register being loaded
	// and the loaded immediate value in the output parameters 'reg' and 'value'
	// respectively.
	uword InstructionPattern::DecodeLoadWordImmediate(uword end,
	Register* reg,
	intptr_t* value) {
	uword start = end - Instr::kInstrSize;
	int32_t instr = Instr::At(start)->InstructionBits();
	intptr_t imm = 0;
	const ARMVersion version = TargetCPUFeatures::arm_version();
	if ((version == ARMv5TE) \|\| (version == ARMv6)) {
	ASSERT((instr & 0xfff00000) == 0xe3800000); // orr rd, rd, byte0
	imm \|= (instr & 0x000000ff);

	start -= Instr::kInstrSize;
	instr = Instr::At(start)->InstructionBits();
	ASSERT((instr & 0xfff00000) == 0xe3800c00); // orr rd, rd, (byte1 rot 12)
	imm \|= (instr & 0x000000ff);

	start -= Instr::kInstrSize;
	instr = Instr::At(start)->InstructionBits();
	ASSERT((instr & 0xfff00f00) == 0xe3800800); // orr rd, rd, (byte2 rot 8)
	imm \|= (instr & 0x000000ff);

	start -= Instr::kInstrSize;
	instr = Instr::At(start)->InstructionBits();
	ASSERT((instr & 0xffff0f00) == 0xe3a00400); // mov rd, (byte3 rot 4)
	imm \|= (instr & 0x000000ff);

	*reg = static_cast<Register>((instr & 0x0000f000) >> 12);
	*value = imm;
	} else {
	ASSERT(version == ARMv7);
	if ((instr & 0xfff00000) == 0xe3400000) { // movt reg, #imm_hi
	imm \|= (instr & 0xf0000) << 12;
	imm \|= (instr & 0xfff) << 16;
	start -= Instr::kInstrSize;
	instr = Instr::At(start)->InstructionBits();
	}
	ASSERT((instr & 0xfff00000) == 0xe3000000); // movw reg, #imm_lo
	imm \|= (instr & 0xf0000) >> 4;
	imm \|= instr & 0xfff;
	*reg = static_cast<Register>((instr & 0xf000) >> 12);
	*value = imm;
	}
	return start;
	}


	// Decodes a load sequence ending at 'end' (the last instruction of the load
	// sequence is the instruction before the one at end). Returns a pointer to
	// the first instruction in the sequence. Returns the register being loaded
	// and the index in the pool being read from in the output parameters 'reg'
	// and 'index' respectively.
	uword InstructionPattern::DecodeLoadWordFromPool(uword end,
	Register* reg,
	intptr_t* index) {
	uword start = end - Instr::kInstrSize;
	int32_t instr = Instr::At(start)->InstructionBits();
	intptr_t offset = 0;
	if ((instr & 0xffff0000) == 0xe59a0000) { // ldr reg, [pp, #+offset]
	offset = instr & 0xfff;
	*reg = static_cast<Register>((instr & 0xf000) >> 12);
	} else {
	ASSERT((instr & 0xfff00000) == 0xe5900000); // ldr reg, [reg, #+offset]
	offset = instr & 0xfff;
	start -= Instr::kInstrSize;
	instr = Instr::At(start)->InstructionBits();
	if ((instr & 0xffff0000) == 0xe28a0000) { // add reg, pp, operand
	const intptr_t rot = (instr & 0xf00) >> 7;
	const intptr_t imm8 = instr & 0xff;
	offset += (imm8 >> rot) \| (imm8 << (32 - rot));
	*reg = static_cast<Register>((instr & 0xf000) >> 12);
	} else {
	ASSERT((instr & 0xffff0000) == 0xe08a0000); // add reg, pp, reg
	end = DecodeLoadWordImmediate(end, reg, &offset);
	}
	}
	offset += kHeapObjectTag;
	ASSERT(Utils::IsAligned(offset, 4));
	*index = (offset - Array::data_offset()) / 4;
	return start;
	}


	RawICData* CallPattern::IcData() {
	if (ic_data_.IsNull()) {
	Register reg;
	args_desc_load_end_ =
	InstructionPattern::DecodeLoadObject(ic_data_load_end_,
	object_pool_,
	&reg,
	&ic_data_);
	ASSERT(reg == R5);
	}
	return ic_data_.raw();
	}


	RawArray* CallPattern::ClosureArgumentsDescriptor() {
	if (args_desc_.IsNull()) {
	IcData(); // Loading of the ic_data must be decoded first, if not already.
	Register reg;
	InstructionPattern::DecodeLoadObject(args_desc_load_end_,
	object_pool_,
	&reg,
	&args_desc_);
	ASSERT(reg == R4);
	}
	return args_desc_.raw();
	}


	uword CallPattern::TargetAddress() const {
	ASSERT(target_address_pool_index_ >= 0);
	const Object& target_address =
	Object::Handle(object_pool_.At(target_address_pool_index_));
	ASSERT(target_address.IsSmi());
	// The address is stored in the object array as a RawSmi.
	return reinterpret_cast<uword>(target_address.raw());
	}


	void CallPattern::SetTargetAddress(uword target_address) const {
	ASSERT(Utils::IsAligned(target_address, 4));
	// The address is stored in the object array as a RawSmi.
	const Smi& smi = Smi::Handle(reinterpret_cast<RawSmi*>(target_address));
	object_pool_.SetAt(target_address_pool_index_, smi);
	// No need to flush the instruction cache, since the code is not modified.
	}


	void CallPattern::InsertAt(uword pc, uword target_address) {
	const ARMVersion version = TargetCPUFeatures::arm_version();
	if ((version == ARMv5TE) \|\| (version == ARMv6)) {
	const uint32_t byte0 = (target_address & 0x000000ff);
	const uint32_t byte1 = (target_address & 0x0000ff00) >> 8;
	const uint32_t byte2 = (target_address & 0x00ff0000) >> 16;
	const uint32_t byte3 = (target_address & 0xff000000) >> 24;

	const uword mov_ip = 0xe3a0c400 \| byte3; // mov ip, (byte3 rot 4)
	const uword or1_ip = 0xe38cc800 \| byte2; // orr ip, ip, (byte2 rot 8)
	const uword or2_ip = 0xe38ccc00 \| byte1; // orr ip, ip, (byte1 rot 12)
	const uword or3_ip = 0xe38cc000 \| byte0; // orr ip, ip, byte0
	const uword blx_ip = 0xe12fff3c;

	reinterpret_cast<uword>(pc + (0 * Instr::kInstrSize)) = mov_ip;
	reinterpret_cast<uword>(pc + (1 * Instr::kInstrSize)) = or1_ip;
	reinterpret_cast<uword>(pc + (2 * Instr::kInstrSize)) = or2_ip;
	reinterpret_cast<uword>(pc + (3 * Instr::kInstrSize)) = or3_ip;
	reinterpret_cast<uword>(pc + (4 * Instr::kInstrSize)) = blx_ip;

	ASSERT(LengthInBytes() == 5 * Instr::kInstrSize);
	CPU::FlushICache(pc, LengthInBytes());
	} else {
	ASSERT(version == ARMv7);
	const uint16_t target_lo = target_address & 0xffff;
	const uint16_t target_hi = target_address >> 16;

	const uword movw_ip =
	0xe300c000 \| ((target_lo >> 12) << 16) \| (target_lo & 0xfff);
	const uword movt_ip =
	0xe340c000 \| ((target_hi >> 12) << 16) \| (target_hi & 0xfff);
	const uword blx_ip = 0xe12fff3c;

	reinterpret_cast<uword>(pc + (0 * Instr::kInstrSize)) = movw_ip;
	reinterpret_cast<uword>(pc + (1 * Instr::kInstrSize)) = movt_ip;
	reinterpret_cast<uword>(pc + (2 * Instr::kInstrSize)) = blx_ip;

	ASSERT(LengthInBytes() == 3 * Instr::kInstrSize);
	CPU::FlushICache(pc, LengthInBytes());
	}
	}


	JumpPattern::JumpPattern(uword pc, const Code& code) : pc_(pc) { }


	int JumpPattern::pattern_length_in_bytes() {
	const ARMVersion version = TargetCPUFeatures::arm_version();
	if ((version == ARMv5TE) \|\| (version == ARMv6)) {
	return 5 * Instr::kInstrSize;
	} else {
	ASSERT(version == ARMv7);
	return 3 * Instr::kInstrSize;
	}
	}


	bool JumpPattern::IsValid() const {
	const ARMVersion version = TargetCPUFeatures::arm_version();
	if ((version == ARMv5TE) \|\| (version == ARMv6)) {
	Instr* mov_ip = Instr::At(pc_ + (0 * Instr::kInstrSize));
	Instr* or1_ip = Instr::At(pc_ + (1 * Instr::kInstrSize));
	Instr* or2_ip = Instr::At(pc_ + (2 * Instr::kInstrSize));
	Instr* or3_ip = Instr::At(pc_ + (3 * Instr::kInstrSize));
	Instr* bx_ip = Instr::At(pc_ + (4 * Instr::kInstrSize));
	return ((mov_ip->InstructionBits() & 0xffffff00) == 0xe3a0c400) &&
	((or1_ip->InstructionBits() & 0xffffff00) == 0xe38cc800) &&
	((or2_ip->InstructionBits() & 0xffffff00) == 0xe38ccc00) &&
	((or3_ip->InstructionBits() & 0xffffff00) == 0xe38cc000) &&
	((bx_ip->InstructionBits() & 0xffffffff) == 0xe12fff1c);
	} else {
	ASSERT(version == ARMv7);
	Instr* movw_ip = Instr::At(pc_ + (0 * Instr::kInstrSize)); // target_lo
	Instr* movt_ip = Instr::At(pc_ + (1 * Instr::kInstrSize)); // target_hi
	Instr* bx_ip = Instr::At(pc_ + (2 * Instr::kInstrSize));
	return (movw_ip->InstructionBits() & 0xfff0f000) == 0xe300c000 &&
	(movt_ip->InstructionBits() & 0xfff0f000) == 0xe340c000 &&
	(bx_ip->InstructionBits() & 0xffffffff) == 0xe12fff1c;
	}
	}


	uword JumpPattern::TargetAddress() const {
	const ARMVersion version = TargetCPUFeatures::arm_version();
	if ((version == ARMv5TE) \|\| (version == ARMv6)) {
	Instr* mov_ip = Instr::At(pc_ + (0 * Instr::kInstrSize));
	Instr* or1_ip = Instr::At(pc_ + (1 * Instr::kInstrSize));
	Instr* or2_ip = Instr::At(pc_ + (2 * Instr::kInstrSize));
	Instr* or3_ip = Instr::At(pc_ + (3 * Instr::kInstrSize));
	uword imm = 0;
	imm \|= or3_ip->Immed8Field();
	imm \|= or2_ip->Immed8Field() << 8;
	imm \|= or1_ip->Immed8Field() << 16;
	imm \|= mov_ip->Immed8Field() << 24;
	return imm;
	} else {
	ASSERT(version == ARMv7);
	Instr* movw_ip = Instr::At(pc_ + (0 * Instr::kInstrSize)); // target_lo
	Instr* movt_ip = Instr::At(pc_ + (1 * Instr::kInstrSize)); // target_hi
	uint16_t target_lo = movw_ip->MovwField();
	uint16_t target_hi = movt_ip->MovwField();
	return (target_hi << 16) \| target_lo;
	}
	}


	void JumpPattern::SetTargetAddress(uword target_address) const {
	const ARMVersion version = TargetCPUFeatures::arm_version();
	if ((version == ARMv5TE) \|\| (version == ARMv6)) {
	const uint32_t byte0 = (target_address & 0x000000ff);
	const uint32_t byte1 = (target_address & 0x0000ff00) >> 8;
	const uint32_t byte2 = (target_address & 0x00ff0000) >> 16;
	const uint32_t byte3 = (target_address & 0xff000000) >> 24;

	const uword mov_ip = 0xe3a0c400 \| byte3; // mov ip, (byte3 rot 4)
	const uword or1_ip = 0xe38cc800 \| byte2; // orr ip, ip, (byte2 rot 8)
	const uword or2_ip = 0xe38ccc00 \| byte1; // orr ip, ip, (byte1 rot 12)
	const uword or3_ip = 0xe38cc000 \| byte0; // orr ip, ip, byte0

	reinterpret_cast<uword>(pc_ + (0 * Instr::kInstrSize)) = mov_ip;
	reinterpret_cast<uword>(pc_ + (1 * Instr::kInstrSize)) = or1_ip;
	reinterpret_cast<uword>(pc_ + (2 * Instr::kInstrSize)) = or2_ip;
	reinterpret_cast<uword>(pc_ + (3 * Instr::kInstrSize)) = or3_ip;
	CPU::FlushICache(pc_, 4 * Instr::kInstrSize);
	} else {
	ASSERT(version == ARMv7);
	const uint16_t target_lo = target_address & 0xffff;
	const uint16_t target_hi = target_address >> 16;

	const uword movw_ip =
	0xe300c000 \| ((target_lo >> 12) << 16) \| (target_lo & 0xfff);
	const uword movt_ip =
	0xe340c000 \| ((target_hi >> 12) << 16) \| (target_hi & 0xfff);

	reinterpret_cast<uword>(pc_ + (0 * Instr::kInstrSize)) = movw_ip;
	reinterpret_cast<uword>(pc_ + (1 * Instr::kInstrSize)) = movt_ip;
	CPU::FlushICache(pc_, 2 * Instr::kInstrSize);
	}
	}

	} // namespace dart

	#endif // defined TARGET_ARCH_ARM