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v8/src/arm/disasm-arm.cc
erik.corry@gmail.com 593c388b39 Fix for bug 512 from Subrato De, CodeAurora. 
Review URL: http://codereview.chromium.org/464016

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3435 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2009-12-09 11:14:45 +00:00

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// Copyright 2007-2009 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
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// A Disassembler object is used to disassemble a block of code instruction by
// instruction. The default implementation of the NameConverter object can be
// overriden to modify register names or to do symbol lookup on addresses.
//
// The example below will disassemble a block of code and print it to stdout.
//
// NameConverter converter;
// Disassembler d(converter);
// for (byte* pc = begin; pc < end;) {
// char buffer[128];
// buffer[0] = '\0';
// byte* prev_pc = pc;
// pc += d.InstructionDecode(buffer, sizeof buffer, pc);
// printf("%p %08x %s\n",
// prev_pc, *reinterpret_cast<int32_t*>(prev_pc), buffer);
// }
//
// The Disassembler class also has a convenience method to disassemble a block
// of code into a FILE*, meaning that the above functionality could also be
// achieved by just calling Disassembler::Disassemble(stdout, begin, end);
#include <assert.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#ifndef WIN32
#include <stdint.h>
#endif
#include "v8.h"
#include "constants-arm.h"
#include "disasm.h"
#include "macro-assembler.h"
#include "platform.h"
namespace assembler {
namespace arm {
namespace v8i = v8::internal;
//------------------------------------------------------------------------------
// Decoder decodes and disassembles instructions into an output buffer.
// It uses the converter to convert register names and call destinations into
// more informative description.
class Decoder {
public:
Decoder(const disasm::NameConverter& converter,
v8::internal::Vector<char> out_buffer)
: converter_(converter),
out_buffer_(out_buffer),
out_buffer_pos_(0) {
out_buffer_[out_buffer_pos_] = '\0';
}
~Decoder() {}
// Writes one disassembled instruction into 'buffer' (0-terminated).
// Returns the length of the disassembled machine instruction in bytes.
int InstructionDecode(byte* instruction);
private:
// Bottleneck functions to print into the out_buffer.
void PrintChar(const char ch);
void Print(const char* str);
// Printing of common values.
void PrintRegister(int reg);
void PrintSRegister(int reg);
void PrintDRegister(int reg);
int FormatVFPRegister(Instr* instr, const char* format);
int FormatVFPinstruction(Instr* instr, const char* format);
void PrintCondition(Instr* instr);
void PrintShiftRm(Instr* instr);
void PrintShiftImm(Instr* instr);
void PrintPU(Instr* instr);
void PrintSoftwareInterrupt(SoftwareInterruptCodes swi);
// Handle formatting of instructions and their options.
int FormatRegister(Instr* instr, const char* option);
int FormatOption(Instr* instr, const char* option);
void Format(Instr* instr, const char* format);
void Unknown(Instr* instr);
// Each of these functions decodes one particular instruction type, a 3-bit
// field in the instruction encoding.
// Types 0 and 1 are combined as they are largely the same except for the way
// they interpret the shifter operand.
void DecodeType01(Instr* instr);
void DecodeType2(Instr* instr);
void DecodeType3(Instr* instr);
void DecodeType4(Instr* instr);
void DecodeType5(Instr* instr);
void DecodeType6(Instr* instr);
void DecodeType7(Instr* instr);
void DecodeUnconditional(Instr* instr);
// For VFP support.
void DecodeTypeVFP(Instr* instr);
void DecodeType6CoprocessorIns(Instr* instr);
const disasm::NameConverter& converter_;
v8::internal::Vector<char> out_buffer_;
int out_buffer_pos_;
DISALLOW_COPY_AND_ASSIGN(Decoder);
};
// Support for assertions in the Decoder formatting functions.
#define STRING_STARTS_WITH(string, compare_string) \
(strncmp(string, compare_string, strlen(compare_string)) == 0)
// Append the ch to the output buffer.
void Decoder::PrintChar(const char ch) {
out_buffer_[out_buffer_pos_++] = ch;
}
// Append the str to the output buffer.
void Decoder::Print(const char* str) {
char cur = *str++;
while (cur != '\0' && (out_buffer_pos_ < (out_buffer_.length() - 1))) {
PrintChar(cur);
cur = *str++;
}
out_buffer_[out_buffer_pos_] = 0;
}
// These condition names are defined in a way to match the native disassembler
// formatting. See for example the command "objdump -d <binary file>".
static const char* cond_names[max_condition] = {
"eq", "ne", "cs" , "cc" , "mi" , "pl" , "vs" , "vc" ,
"hi", "ls", "ge", "lt", "gt", "le", "", "invalid",
};
// Print the condition guarding the instruction.
void Decoder::PrintCondition(Instr* instr) {
Print(cond_names[instr->ConditionField()]);
}
// Print the register name according to the active name converter.
void Decoder::PrintRegister(int reg) {
Print(converter_.NameOfCPURegister(reg));
}
// Print the VFP S register name according to the active name converter.
void Decoder::PrintSRegister(int reg) {
Print(assembler::arm::VFPRegisters::Name(reg));
}
// Print the VFP D register name according to the active name converter.
void Decoder::PrintDRegister(int reg) {
Print(assembler::arm::VFPRegisters::Name(reg + 32));
}
// These shift names are defined in a way to match the native disassembler
// formatting. See for example the command "objdump -d <binary file>".
static const char* shift_names[max_shift] = {
"lsl", "lsr", "asr", "ror"
};
// Print the register shift operands for the instruction. Generally used for
// data processing instructions.
void Decoder::PrintShiftRm(Instr* instr) {
Shift shift = instr->ShiftField();
int shift_amount = instr->ShiftAmountField();
int rm = instr->RmField();
PrintRegister(rm);
if ((instr->RegShiftField() == 0) && (shift == LSL) && (shift_amount == 0)) {
// Special case for using rm only.
return;
}
if (instr->RegShiftField() == 0) {
// by immediate
if ((shift == ROR) && (shift_amount == 0)) {
Print(", RRX");
return;
} else if (((shift == LSR) || (shift == ASR)) && (shift_amount == 0)) {
shift_amount = 32;
}
out_buffer_pos_ += v8i::OS::SNPrintF(out_buffer_ + out_buffer_pos_,
", %s #%d",
shift_names[shift], shift_amount);
} else {
// by register
int rs = instr->RsField();
out_buffer_pos_ += v8i::OS::SNPrintF(out_buffer_ + out_buffer_pos_,
", %s ", shift_names[shift]);
PrintRegister(rs);
}
}
// Print the immediate operand for the instruction. Generally used for data
// processing instructions.
void Decoder::PrintShiftImm(Instr* instr) {
int rotate = instr->RotateField() * 2;
int immed8 = instr->Immed8Field();
int imm = (immed8 >> rotate) | (immed8 << (32 - rotate));
out_buffer_pos_ += v8i::OS::SNPrintF(out_buffer_ + out_buffer_pos_,
"#%d", imm);
}
// Print PU formatting to reduce complexity of FormatOption.
void Decoder::PrintPU(Instr* instr) {
switch (instr->PUField()) {
case 0: {
Print("da");
break;
}
case 1: {
Print("ia");
break;
}
case 2: {
Print("db");
break;
}
case 3: {
Print("ib");
break;
}
default: {
UNREACHABLE();
break;
}
}
}
// Print SoftwareInterrupt codes. Factoring this out reduces the complexity of
// the FormatOption method.
void Decoder::PrintSoftwareInterrupt(SoftwareInterruptCodes swi) {
switch (swi) {
case call_rt_redirected:
Print("call_rt_redirected");
return;
case break_point:
Print("break_point");
return;
default:
out_buffer_pos_ += v8i::OS::SNPrintF(out_buffer_ + out_buffer_pos_,
"%d",
swi);
return;
}
}
// Handle all register based formatting in this function to reduce the
// complexity of FormatOption.
int Decoder::FormatRegister(Instr* instr, const char* format) {
ASSERT(format[0] == 'r');
if (format[1] == 'n') { // 'rn: Rn register
int reg = instr->RnField();
PrintRegister(reg);
return 2;
} else if (format[1] == 'd') { // 'rd: Rd register
int reg = instr->RdField();
PrintRegister(reg);
return 2;
} else if (format[1] == 's') { // 'rs: Rs register
int reg = instr->RsField();
PrintRegister(reg);
return 2;
} else if (format[1] == 'm') { // 'rm: Rm register
int reg = instr->RmField();
PrintRegister(reg);
return 2;
} else if (format[1] == 't') { // 'rt: Rt register
int reg = instr->RtField();
PrintRegister(reg);
return 2;
} else if (format[1] == 'l') {
// 'rlist: register list for load and store multiple instructions
ASSERT(STRING_STARTS_WITH(format, "rlist"));
int rlist = instr->RlistField();
int reg = 0;
Print("{");
// Print register list in ascending order, by scanning the bit mask.
while (rlist != 0) {
if ((rlist & 1) != 0) {
PrintRegister(reg);
if ((rlist >> 1) != 0) {
Print(", ");
}
}
reg++;
rlist >>= 1;
}
Print("}");
return 5;
}
UNREACHABLE();
return -1;
}
// Handle all VFP register based formatting in this function to reduce the
// complexity of FormatOption.
int Decoder::FormatVFPRegister(Instr* instr, const char* format) {
ASSERT((format[0] == 'S') || (format[0] == 'D'));
if (format[1] == 'n') {
int reg = instr->VnField();
if (format[0] == 'S') PrintSRegister(((reg << 1) | instr->NField()));
if (format[0] == 'D') PrintDRegister(reg);
return 2;
} else if (format[1] == 'm') {
int reg = instr->VmField();
if (format[0] == 'S') PrintSRegister(((reg << 1) | instr->MField()));
if (format[0] == 'D') PrintDRegister(reg);
return 2;
} else if (format[1] == 'd') {
int reg = instr->VdField();
if (format[0] == 'S') PrintSRegister(((reg << 1) | instr->DField()));
if (format[0] == 'D') PrintDRegister(reg);
return 2;
}
UNREACHABLE();
return -1;
}
int Decoder::FormatVFPinstruction(Instr* instr, const char* format) {
Print(format);
return 0;
}
// FormatOption takes a formatting string and interprets it based on
// the current instructions. The format string points to the first
// character of the option string (the option escape has already been
// consumed by the caller.) FormatOption returns the number of
// characters that were consumed from the formatting string.
int Decoder::FormatOption(Instr* instr, const char* format) {
switch (format[0]) {
case 'a': { // 'a: accumulate multiplies
if (instr->Bit(21) == 0) {
Print("ul");
} else {
Print("la");
}
return 1;
}
case 'b': { // 'b: byte loads or stores
if (instr->HasB()) {
Print("b");
}
return 1;
}
case 'c': { // 'cond: conditional execution
ASSERT(STRING_STARTS_WITH(format, "cond"));
PrintCondition(instr);
return 4;
}
case 'h': { // 'h: halfword operation for extra loads and stores
if (instr->HasH()) {
Print("h");
} else {
Print("b");
}
return 1;
}
case 'l': { // 'l: branch and link
if (instr->HasLink()) {
Print("l");
}
return 1;
}
case 'm': {
if (format[1] == 'e') { // 'memop: load/store instructions
ASSERT(STRING_STARTS_WITH(format, "memop"));
if (instr->HasL()) {
Print("ldr");
} else {
Print("str");
}
return 5;
}
// 'msg: for simulator break instructions
ASSERT(STRING_STARTS_WITH(format, "msg"));
byte* str =
reinterpret_cast<byte*>(instr->InstructionBits() & 0x0fffffff);
out_buffer_pos_ += v8i::OS::SNPrintF(out_buffer_ + out_buffer_pos_,
"%s", converter_.NameInCode(str));
return 3;
}
case 'o': {
if (format[3] == '1') {
// 'off12: 12-bit offset for load and store instructions
ASSERT(STRING_STARTS_WITH(format, "off12"));
out_buffer_pos_ += v8i::OS::SNPrintF(out_buffer_ + out_buffer_pos_,
"%d", instr->Offset12Field());
return 5;
}
// 'off8: 8-bit offset for extra load and store instructions
ASSERT(STRING_STARTS_WITH(format, "off8"));
int offs8 = (instr->ImmedHField() << 4) | instr->ImmedLField();
out_buffer_pos_ += v8i::OS::SNPrintF(out_buffer_ + out_buffer_pos_,
"%d", offs8);
return 4;
}
case 'p': { // 'pu: P and U bits for load and store instructions
ASSERT(STRING_STARTS_WITH(format, "pu"));
PrintPU(instr);
return 2;
}
case 'r': {
return FormatRegister(instr, format);
}
case 's': {
if (format[1] == 'h') { // 'shift_op or 'shift_rm
if (format[6] == 'o') { // 'shift_op
ASSERT(STRING_STARTS_WITH(format, "shift_op"));
if (instr->TypeField() == 0) {
PrintShiftRm(instr);
} else {
ASSERT(instr->TypeField() == 1);
PrintShiftImm(instr);
}
return 8;
} else { // 'shift_rm
ASSERT(STRING_STARTS_WITH(format, "shift_rm"));
PrintShiftRm(instr);
return 8;
}
} else if (format[1] == 'w') { // 'swi
ASSERT(STRING_STARTS_WITH(format, "swi"));
PrintSoftwareInterrupt(instr->SwiField());
return 3;
} else if (format[1] == 'i') { // 'sign: signed extra loads and stores
ASSERT(STRING_STARTS_WITH(format, "sign"));
if (instr->HasSign()) {
Print("s");
}
return 4;
}
// 's: S field of data processing instructions
if (instr->HasS()) {
Print("s");
}
return 1;
}
case 't': { // 'target: target of branch instructions
ASSERT(STRING_STARTS_WITH(format, "target"));
int off = (instr->SImmed24Field() << 2) + 8;
out_buffer_pos_ += v8i::OS::SNPrintF(
out_buffer_ + out_buffer_pos_,
"%+d -> %s",
off,
converter_.NameOfAddress(reinterpret_cast<byte*>(instr) + off));
return 6;
}
case 'u': { // 'u: signed or unsigned multiplies
// The manual gets the meaning of bit 22 backwards in the multiply
// instruction overview on page A3.16.2. The instructions that
// exist in u and s variants are the following:
// smull A4.1.87
// umull A4.1.129
// umlal A4.1.128
// smlal A4.1.76
// For these 0 means u and 1 means s. As can be seen on their individual
// pages. The other 18 mul instructions have the bit set or unset in
// arbitrary ways that are unrelated to the signedness of the instruction.
// None of these 18 instructions exist in both a 'u' and an 's' variant.
if (instr->Bit(22) == 0) {
Print("u");
} else {
Print("s");
}
return 1;
}
case 'v': {
return FormatVFPinstruction(instr, format);
}
case 'S':
case 'D': {
return FormatVFPRegister(instr, format);
}
case 'w': { // 'w: W field of load and store instructions
if (instr->HasW()) {
Print("!");
}
return 1;
}
default: {
UNREACHABLE();
break;
}
}
UNREACHABLE();
return -1;
}
// Format takes a formatting string for a whole instruction and prints it into
// the output buffer. All escaped options are handed to FormatOption to be
// parsed further.
void Decoder::Format(Instr* instr, const char* format) {
char cur = *format++;
while ((cur != 0) && (out_buffer_pos_ < (out_buffer_.length() - 1))) {
if (cur == '\'') { // Single quote is used as the formatting escape.
format += FormatOption(instr, format);
} else {
out_buffer_[out_buffer_pos_++] = cur;
}
cur = *format++;
}
out_buffer_[out_buffer_pos_] = '\0';
}
// For currently unimplemented decodings the disassembler calls Unknown(instr)
// which will just print "unknown" of the instruction bits.
void Decoder::Unknown(Instr* instr) {
Format(instr, "unknown");
}
void Decoder::DecodeType01(Instr* instr) {
int type = instr->TypeField();
if ((type == 0) && instr->IsSpecialType0()) {
// multiply instruction or extra loads and stores
if (instr->Bits(7, 4) == 9) {
if (instr->Bit(24) == 0) {
// multiply instructions
if (instr->Bit(23) == 0) {
if (instr->Bit(21) == 0) {
// The MUL instruction description (A 4.1.33) refers to Rd as being
// the destination for the operation, but it confusingly uses the
// Rn field to encode it.
Format(instr, "mul'cond's 'rn, 'rm, 'rs");
} else {
// The MLA instruction description (A 4.1.28) refers to the order
// of registers as "Rd, Rm, Rs, Rn". But confusingly it uses the
// Rn field to encode the Rd register and the Rd field to encode
// the Rn register.
Format(instr, "mla'cond's 'rn, 'rm, 'rs, 'rd");
}
} else {
// The signed/long multiply instructions use the terms RdHi and RdLo
// when referring to the target registers. They are mapped to the Rn
// and Rd fields as follows:
// RdLo == Rd field
// RdHi == Rn field
// The order of registers is: <RdLo>, <RdHi>, <Rm>, <Rs>
Format(instr, "'um'al'cond's 'rd, 'rn, 'rm, 'rs");
}
} else {
Unknown(instr); // not used by V8
}
} else {
// extra load/store instructions
switch (instr->PUField()) {
case 0: {
if (instr->Bit(22) == 0) {
Format(instr, "'memop'cond'sign'h 'rd, ['rn], -'rm");
} else {
Format(instr, "'memop'cond'sign'h 'rd, ['rn], #-'off8");
}
break;
}
case 1: {
if (instr->Bit(22) == 0) {
Format(instr, "'memop'cond'sign'h 'rd, ['rn], +'rm");
} else {
Format(instr, "'memop'cond'sign'h 'rd, ['rn], #+'off8");
}
break;
}
case 2: {
if (instr->Bit(22) == 0) {
Format(instr, "'memop'cond'sign'h 'rd, ['rn, -'rm]'w");
} else {
Format(instr, "'memop'cond'sign'h 'rd, ['rn, #-'off8]'w");
}
break;
}
case 3: {
if (instr->Bit(22) == 0) {
Format(instr, "'memop'cond'sign'h 'rd, ['rn, +'rm]'w");
} else {
Format(instr, "'memop'cond'sign'h 'rd, ['rn, #+'off8]'w");
}
break;
}
default: {
// The PU field is a 2-bit field.
UNREACHABLE();
break;
}
}
return;
}
} else {
switch (instr->OpcodeField()) {
case AND: {
Format(instr, "and'cond's 'rd, 'rn, 'shift_op");
break;
}
case EOR: {
Format(instr, "eor'cond's 'rd, 'rn, 'shift_op");
break;
}
case SUB: {
Format(instr, "sub'cond's 'rd, 'rn, 'shift_op");
break;
}
case RSB: {
Format(instr, "rsb'cond's 'rd, 'rn, 'shift_op");
break;
}
case ADD: {
Format(instr, "add'cond's 'rd, 'rn, 'shift_op");
break;
}
case ADC: {
Format(instr, "adc'cond's 'rd, 'rn, 'shift_op");
break;
}
case SBC: {
Format(instr, "sbc'cond's 'rd, 'rn, 'shift_op");
break;
}
case RSC: {
Format(instr, "rsc'cond's 'rd, 'rn, 'shift_op");
break;
}
case TST: {
if (instr->HasS()) {
Format(instr, "tst'cond 'rn, 'shift_op");
} else {
Unknown(instr); // not used by V8
}
break;
}
case TEQ: {
if (instr->HasS()) {
Format(instr, "teq'cond 'rn, 'shift_op");
} else {
switch (instr->Bits(7, 4)) {
case BX:
Format(instr, "bx'cond 'rm");
break;
case BLX:
Format(instr, "blx'cond 'rm");
break;
default:
Unknown(instr); // not used by V8
break;
}
}
break;
}
case CMP: {
if (instr->HasS()) {
Format(instr, "cmp'cond 'rn, 'shift_op");
} else {
Unknown(instr); // not used by V8
}
break;
}
case CMN: {
if (instr->HasS()) {
Format(instr, "cmn'cond 'rn, 'shift_op");
} else {
switch (instr->Bits(7, 4)) {
case CLZ:
Format(instr, "clz'cond 'rd, 'rm");
break;
default:
Unknown(instr); // not used by V8
break;
}
}
break;
}
case ORR: {
Format(instr, "orr'cond's 'rd, 'rn, 'shift_op");
break;
}
case MOV: {
Format(instr, "mov'cond's 'rd, 'shift_op");
break;
}
case BIC: {
Format(instr, "bic'cond's 'rd, 'rn, 'shift_op");
break;
}
case MVN: {
Format(instr, "mvn'cond's 'rd, 'shift_op");
break;
}
default: {
// The Opcode field is a 4-bit field.
UNREACHABLE();
break;
}
}
}
}
void Decoder::DecodeType2(Instr* instr) {
switch (instr->PUField()) {
case 0: {
if (instr->HasW()) {
Unknown(instr); // not used in V8
}
Format(instr, "'memop'cond'b 'rd, ['rn], #-'off12");
break;
}
case 1: {
if (instr->HasW()) {
Unknown(instr); // not used in V8
}
Format(instr, "'memop'cond'b 'rd, ['rn], #+'off12");
break;
}
case 2: {
Format(instr, "'memop'cond'b 'rd, ['rn, #-'off12]'w");
break;
}
case 3: {
Format(instr, "'memop'cond'b 'rd, ['rn, #+'off12]'w");
break;
}
default: {
// The PU field is a 2-bit field.
UNREACHABLE();
break;
}
}
}
void Decoder::DecodeType3(Instr* instr) {
switch (instr->PUField()) {
case 0: {
ASSERT(!instr->HasW());
Format(instr, "'memop'cond'b 'rd, ['rn], -'shift_rm");
break;
}
case 1: {
ASSERT(!instr->HasW());
Format(instr, "'memop'cond'b 'rd, ['rn], +'shift_rm");
break;
}
case 2: {
Format(instr, "'memop'cond'b 'rd, ['rn, -'shift_rm]'w");
break;
}
case 3: {
Format(instr, "'memop'cond'b 'rd, ['rn, +'shift_rm]'w");
break;
}
default: {
// The PU field is a 2-bit field.
UNREACHABLE();
break;
}
}
}
void Decoder::DecodeType4(Instr* instr) {
ASSERT(instr->Bit(22) == 0); // Privileged mode currently not supported.
if (instr->HasL()) {
Format(instr, "ldm'cond'pu 'rn'w, 'rlist");
} else {
Format(instr, "stm'cond'pu 'rn'w, 'rlist");
}
}
void Decoder::DecodeType5(Instr* instr) {
Format(instr, "b'l'cond 'target");
}
void Decoder::DecodeType6(Instr* instr) {
DecodeType6CoprocessorIns(instr);
}
void Decoder::DecodeType7(Instr* instr) {
if (instr->Bit(24) == 1) {
Format(instr, "swi'cond 'swi");
} else {
DecodeTypeVFP(instr);
}
}
void Decoder::DecodeUnconditional(Instr* instr) {
if (instr->Bits(7, 4) == 0xB && instr->Bits(27, 25) == 0 && instr->HasL()) {
Format(instr, "'memop'h'pu 'rd, ");
bool immediate = instr->HasB();
switch (instr->PUField()) {
case 0: {
// Post index, negative.
if (instr->HasW()) {
Unknown(instr);
break;
}
if (immediate) {
Format(instr, "['rn], #-'imm12");
} else {
Format(instr, "['rn], -'rm");
}
break;
}
case 1: {
// Post index, positive.
if (instr->HasW()) {
Unknown(instr);
break;
}
if (immediate) {
Format(instr, "['rn], #+'imm12");
} else {
Format(instr, "['rn], +'rm");
}
break;
}
case 2: {
// Pre index or offset, negative.
if (immediate) {
Format(instr, "['rn, #-'imm12]'w");
} else {
Format(instr, "['rn, -'rm]'w");
}
break;
}
case 3: {
// Pre index or offset, positive.
if (immediate) {
Format(instr, "['rn, #+'imm12]'w");
} else {
Format(instr, "['rn, +'rm]'w");
}
break;
}
default: {
// The PU field is a 2-bit field.
UNREACHABLE();
break;
}
}
return;
}
Format(instr, "break 'msg");
}
// void Decoder::DecodeTypeVFP(Instr* instr)
// vmov: Sn = Rt
// vmov: Rt = Sn
// vcvt: Dd = Sm
// vcvt: Sd = Dm
// Dd = vadd(Dn, Dm)
// Dd = vsub(Dn, Dm)
// Dd = vmul(Dn, Dm)
// Dd = vdiv(Dn, Dm)
// vcmp(Dd, Dm)
// VMRS
void Decoder::DecodeTypeVFP(Instr* instr) {
ASSERT((instr->TypeField() == 7) && (instr->Bit(24) == 0x0) );
if (instr->Bit(23) == 1) {
if ((instr->Bits(21, 19) == 0x7) &&
(instr->Bits(18, 16) == 0x5) &&
(instr->Bits(11, 9) == 0x5) &&
(instr->Bit(8) == 1) &&
(instr->Bit(6) == 1) &&
(instr->Bit(4) == 0)) {
Format(instr, "vcvt.s32.f64'cond 'Sd, 'Dm");
} else if ((instr->Bits(21, 19) == 0x7) &&
(instr->Bits(18, 16) == 0x0) &&
(instr->Bits(11, 9) == 0x5) &&
(instr->Bit(8) == 1) &&
(instr->Bit(7) == 1) &&
(instr->Bit(6) == 1) &&
(instr->Bit(4) == 0)) {
Format(instr, "vcvt.f64.s32'cond 'Dd, 'Sm");
} else if ((instr->Bit(21) == 0x0) &&
(instr->Bit(20) == 0x0) &&
(instr->Bits(11, 9) == 0x5) &&
(instr->Bit(8) == 1) &&
(instr->Bit(6) == 0) &&
(instr->Bit(4) == 0)) {
Format(instr, "vdiv.f64'cond 'Dd, 'Dn, 'Dm");
} else if ((instr->Bits(21, 20) == 0x3) &&
(instr->Bits(19, 16) == 0x4) &&
(instr->Bits(11, 9) == 0x5) &&
(instr->Bit(8) == 0x1) &&
(instr->Bit(6) == 0x1) &&
(instr->Bit(4) == 0x0)) {
Format(instr, "vcmp.f64'cond 'Dd, 'Dm");
} else if ((instr->Bits(23, 20) == 0xF) &&
(instr->Bits(19, 16) == 0x1) &&
(instr->Bits(11, 8) == 0xA) &&
(instr->Bits(7, 5) == 0x0) &&
(instr->Bit(4) == 0x1) &&
(instr->Bits(3, 0) == 0x0)) {
if (instr->Bits(15, 12) == 0xF)
Format(instr, "vmrs'cond APSR, FPSCR");
else
Unknown(instr); // Not used by V8.
} else {
Unknown(instr); // Not used by V8.
}
} else if (instr->Bit(21) == 1) {
if ((instr->Bit(20) == 0x1) &&
(instr->Bits(11, 9) == 0x5) &&
(instr->Bit(8) == 0x1) &&
(instr->Bit(6) == 0) &&
(instr->Bit(4) == 0)) {
Format(instr, "vadd.f64'cond 'Dd, 'Dn, 'Dm");
} else if ((instr->Bit(20) == 0x1) &&
(instr->Bits(11, 9) == 0x5) &&
(instr->Bit(8) == 0x1) &&
(instr->Bit(6) == 1) &&
(instr->Bit(4) == 0)) {
Format(instr, "vsub.f64'cond 'Dd, 'Dn, 'Dm");
} else if ((instr->Bit(20) == 0x0) &&
(instr->Bits(11, 9) == 0x5) &&
(instr->Bit(8) == 0x1) &&
(instr->Bit(6) == 0) &&
(instr->Bit(4) == 0)) {
Format(instr, "vmul.f64'cond 'Dd, 'Dn, 'Dm");
} else {
Unknown(instr); // Not used by V8.
}
} else {
if ((instr->Bit(20) == 0x0) &&
(instr->Bits(11, 8) == 0xA) &&
(instr->Bits(6, 5) == 0x0) &&
(instr->Bit(4) == 1) &&
(instr->Bits(3, 0) == 0x0)) {
Format(instr, "vmov'cond 'Sn, 'rt");
} else if ((instr->Bit(20) == 0x1) &&
(instr->Bits(11, 8) == 0xA) &&
(instr->Bits(6, 5) == 0x0) &&
(instr->Bit(4) == 1) &&
(instr->Bits(3, 0) == 0x0)) {
Format(instr, "vmov'cond 'rt, 'Sn");
} else {
Unknown(instr); // Not used by V8.
}
}
}
// Decode Type 6 coprocessor instructions.
// Dm = vmov(Rt, Rt2)
// <Rt, Rt2> = vmov(Dm)
void Decoder::DecodeType6CoprocessorIns(Instr* instr) {
ASSERT((instr->TypeField() == 6));
if (instr->Bit(23) == 1) {
Unknown(instr); // Not used by V8.
} else if (instr->Bit(22) == 1) {
if ((instr->Bits(27, 24) == 0xC) &&
(instr->Bit(22) == 1) &&
(instr->Bits(11, 8) == 0xB) &&
(instr->Bits(7, 6) == 0x0) &&
(instr->Bit(4) == 1)) {
if (instr->Bit(20) == 0) {
Format(instr, "vmov'cond 'Dm, 'rt, 'rn");
} else if (instr->Bit(20) == 1) {
Format(instr, "vmov'cond 'rt, 'rn, 'Dm");
}
} else {
Unknown(instr); // Not used by V8.
}
} else if (instr->Bit(21) == 1) {
Unknown(instr); // Not used by V8.
} else {
Unknown(instr); // Not used by V8.
}
}
// Disassemble the instruction at *instr_ptr into the output buffer.
int Decoder::InstructionDecode(byte* instr_ptr) {
Instr* instr = Instr::At(instr_ptr);
// Print raw instruction bytes.
out_buffer_pos_ += v8i::OS::SNPrintF(out_buffer_ + out_buffer_pos_,
"%08x ",
instr->InstructionBits());
if (instr->ConditionField() == special_condition) {
DecodeUnconditional(instr);
return Instr::kInstrSize;
}
switch (instr->TypeField()) {
case 0:
case 1: {
DecodeType01(instr);
break;
}
case 2: {
DecodeType2(instr);
break;
}
case 3: {
DecodeType3(instr);
break;
}
case 4: {
DecodeType4(instr);
break;
}
case 5: {
DecodeType5(instr);
break;
}
case 6: {
DecodeType6(instr);
break;
}
case 7: {
DecodeType7(instr);
break;
}
default: {
// The type field is 3-bits in the ARM encoding.
UNREACHABLE();
break;
}
}
return Instr::kInstrSize;
}
} } // namespace assembler::arm
//------------------------------------------------------------------------------
namespace disasm {
namespace v8i = v8::internal;
const char* NameConverter::NameOfAddress(byte* addr) const {
static v8::internal::EmbeddedVector<char, 32> tmp_buffer;
v8::internal::OS::SNPrintF(tmp_buffer, "%p", addr);
return tmp_buffer.start();
}
const char* NameConverter::NameOfConstant(byte* addr) const {
return NameOfAddress(addr);
}
const char* NameConverter::NameOfCPURegister(int reg) const {
return assembler::arm::Registers::Name(reg);
}
const char* NameConverter::NameOfByteCPURegister(int reg) const {
UNREACHABLE(); // ARM does not have the concept of a byte register
return "nobytereg";
}
const char* NameConverter::NameOfXMMRegister(int reg) const {
UNREACHABLE(); // ARM does not have any XMM registers
return "noxmmreg";
}
const char* NameConverter::NameInCode(byte* addr) const {
// The default name converter is called for unknown code. So we will not try
// to access any memory.
return "";
}
//------------------------------------------------------------------------------
Disassembler::Disassembler(const NameConverter& converter)
: converter_(converter) {}
Disassembler::~Disassembler() {}
int Disassembler::InstructionDecode(v8::internal::Vector<char> buffer,
byte* instruction) {
assembler::arm::Decoder d(converter_, buffer);
return d.InstructionDecode(instruction);
}
int Disassembler::ConstantPoolSizeAt(byte* instruction) {
int instruction_bits = *(reinterpret_cast<int*>(instruction));
if ((instruction_bits & 0xfff00000) == 0x03000000) {
return instruction_bits & 0x0000ffff;
} else {
return -1;
}
}
void Disassembler::Disassemble(FILE* f, byte* begin, byte* end) {
NameConverter converter;
Disassembler d(converter);
for (byte* pc = begin; pc < end;) {
v8::internal::EmbeddedVector<char, 128> buffer;
buffer[0] = '\0';
byte* prev_pc = pc;
pc += d.InstructionDecode(buffer, pc);
fprintf(f, "%p %08x %s\n",
prev_pc, *reinterpret_cast<int32_t*>(prev_pc), buffer.start());
}
}
} // namespace disasm
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