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// 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/disassembler.h"
#include "vm/globals.h" // Needed here to get TARGET_ARCH_MIPS.
#if defined(TARGET_ARCH_MIPS)
#include "platform/assert.h"
namespace dart {
class MIPSDecoder : public ValueObject {
public:
MIPSDecoder(char* buffer, size_t buffer_size)
: buffer_(buffer),
buffer_size_(buffer_size),
buffer_pos_(0) {
buffer_[buffer_pos_] = '\0';
}
~MIPSDecoder() {}
// Writes one disassembled instruction into 'buffer' (0-terminated).
// Returns true if the instruction was successfully decoded, false otherwise.
void InstructionDecode(Instr* instr);
private:
// Bottleneck functions to print into the out_buffer.
void Print(const char* str);
// Printing of common values.
void PrintRegister(Register reg);
void PrintFRegister(FRegister reg);
void PrintFormat(Instr* instr);
int FormatRegister(Instr* instr, const char* format);
int FormatFRegister(Instr* instr, const char* format);
int FormatOption(Instr* instr, const char* format);
void Format(Instr* instr, const char* format);
void Unknown(Instr* instr);
void DecodeSpecial(Instr* instr);
void DecodeSpecial2(Instr* instr);
void DecodeRegImm(Instr* instr);
void DecodeCop1(Instr* instr);
// Convenience functions.
char* get_buffer() const { return buffer_; }
char* current_position_in_buffer() { return buffer_ + buffer_pos_; }
size_t remaining_size_in_buffer() { return buffer_size_ - buffer_pos_; }
char* buffer_; // Decode instructions into this buffer.
size_t buffer_size_; // The size of the character buffer.
size_t buffer_pos_; // Current character position in buffer.
DISALLOW_ALLOCATION();
DISALLOW_COPY_AND_ASSIGN(MIPSDecoder);
};
// Support for assertions in the MIPSDecoder formatting functions.
#define STRING_STARTS_WITH(string, compare_string) \
(strncmp(string, compare_string, strlen(compare_string)) == 0)
// Append the str to the output buffer.
void MIPSDecoder::Print(const char* str) {
char cur = *str++;
while (cur != '\0' && (buffer_pos_ < (buffer_size_ - 1))) {
buffer_[buffer_pos_++] = cur;
cur = *str++;
}
buffer_[buffer_pos_] = '\0';
}
static const char* reg_names[kNumberOfCpuRegisters] = {
"r0" , "r1" , "r2" , "r3" , "r4" , "r5" , "r6" , "r7" ,
"r8" , "r9" , "r10", "r11", "r12", "r13", "r14", "r15",
"r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
"r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
};
static const char* freg_names[kNumberOfFRegisters] = {
"f0" , "f1" , "f2" , "f3" , "f4" , "f5" , "f6" , "f7" ,
"f8" , "f9" , "f10", "f11", "f12", "f13", "f14", "f15",
"f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23",
"f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31",
};
void MIPSDecoder::PrintRegister(Register reg) {
ASSERT(0 <= reg);
ASSERT(reg < kNumberOfCpuRegisters);
Print(reg_names[reg]);
}
void MIPSDecoder::PrintFRegister(FRegister reg) {
ASSERT(0 <= reg);
ASSERT(reg < kNumberOfFRegisters);
Print(freg_names[reg]);
}
// Handle all register based formatting in these functions to reduce the
// complexity of FormatOption.
int MIPSDecoder::FormatRegister(Instr* instr, const char* format) {
ASSERT(format[0] == 'r');
switch (format[1]) {
case 's': { // 'rs: Rs register
PrintRegister(instr->RsField());
return 2;
}
case 't': { // 'rt: Rt register
PrintRegister(instr->RtField());
return 2;
}
case 'd': { // 'rd: Rd register
PrintRegister(instr->RdField());
return 2;
}
}
UNREACHABLE();
return -1;
}
int MIPSDecoder::FormatFRegister(Instr* instr, const char* format) {
ASSERT(format[0] == 'f');
switch (format[1]) {
case 's': { // 'fs: Fs register
PrintFRegister(instr->FsField());
return 2;
}
case 't': { // 'ft: Ft register
PrintFRegister(instr->FtField());
return 2;
}
case 'd': { // 'fd: Fd register
PrintFRegister(instr->FdField());
return 2;
}
}
UNREACHABLE();
return -1;
}
void MIPSDecoder::PrintFormat(Instr *instr) {
switch (instr->FormatField()) {
case FMT_S: {
Print("s");
break;
}
case FMT_D: {
Print("d");
break;
}
case FMT_W: {
Print("w");
break;
}
case FMT_L: {
Print("l");
break;
}
case FMT_PS: {
Print("ps");
break;
}
default: {
Print("unknown");
break;
}
}
}
// 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 MIPSDecoder::FormatOption(Instr* instr, const char* format) {
switch (format[0]) {
case 'c': {
ASSERT(STRING_STARTS_WITH(format, "code"));
buffer_pos_ += OS::SNPrint(current_position_in_buffer(),
remaining_size_in_buffer(),
"0x%x",
instr->BreakCodeField());
return 4;
}
case 'h': {
ASSERT(STRING_STARTS_WITH(format, "hint"));
if (instr->SaField() == 0x10) {
// The high bit of the SA field is the only one that means something for
// JALR and JR. TODO(zra): Fill in the other cases for PREF if needed.
buffer_pos_ += OS::SNPrint(current_position_in_buffer(),
remaining_size_in_buffer(),
".hb");
} else if (instr->SaField() != 0) {
buffer_pos_ += OS::SNPrint(current_position_in_buffer(),
remaining_size_in_buffer(),
".unknown");
}
return 4;
}
case 'd': {
ASSERT(STRING_STARTS_WITH(format, "dest"));
int off = instr->SImmField() << 2;
uword destination =
reinterpret_cast<uword>(instr) + off + Instr::kInstrSize;
buffer_pos_ += OS::SNPrint(current_position_in_buffer(),
remaining_size_in_buffer(),
"%#" Px "",
destination);
return 4;
}
case 'i': {
ASSERT(STRING_STARTS_WITH(format, "imm"));
if (format[3] == 'u') {
int32_t imm = instr->UImmField();
buffer_pos_ += OS::SNPrint(current_position_in_buffer(),
remaining_size_in_buffer(),
"0x%x",
imm);
} else {
ASSERT(STRING_STARTS_WITH(format, "imms"));
int32_t imm = instr->SImmField();
buffer_pos_ += OS::SNPrint(current_position_in_buffer(),
remaining_size_in_buffer(),
"%d",
imm);
}
return 4;
}
case 'r': {
return FormatRegister(instr, format);
}
case 'f': {
if (format[1] == 'm') {
ASSERT(STRING_STARTS_WITH(format, "fmt"));
PrintFormat(instr);
return 3;
} else {
return FormatFRegister(instr, format);
}
}
case 's': {
ASSERT(STRING_STARTS_WITH(format, "sa"));
buffer_pos_ += OS::SNPrint(current_position_in_buffer(),
remaining_size_in_buffer(),
"%d",
instr->SaField());
return 2;
}
default: {
UNREACHABLE();
}
}
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 MIPSDecoder::Format(Instr* instr, const char* format) {
char cur = *format++;
while ((cur != 0) && (buffer_pos_ < (buffer_size_ - 1))) {
if (cur == '\'') { // Single quote is used as the formatting escape.
format += FormatOption(instr, format);
} else {
buffer_[buffer_pos_++] = cur;
}
cur = *format++;
}
buffer_[buffer_pos_] = '\0';
}
// For currently unimplemented decodings the disassembler calls Unknown(instr)
// which will just print "unknown" of the instruction bits.
void MIPSDecoder::Unknown(Instr* instr) {
Format(instr, "unknown");
}
void MIPSDecoder::DecodeSpecial(Instr* instr) {
ASSERT(instr->OpcodeField() == SPECIAL);
switch (instr->FunctionField()) {
case ADDU: {
Format(instr, "addu 'rd, 'rs, 'rt");
break;
}
case AND: {
Format(instr, "and 'rd, 'rs, 'rt");
break;
}
case BREAK: {
Format(instr, "break 'code");
if (instr->BreakCodeField() == Instr::kStopMessageCode) {
const char* message = *reinterpret_cast<const char**>(
reinterpret_cast<intptr_t>(instr) - Instr::kInstrSize);
buffer_pos_ += OS::SNPrint(current_position_in_buffer(),
remaining_size_in_buffer(),
" ; \"%s\"",
message);
}
break;
}
case DIV: {
Format(instr, "div 'rs, 'rt");
break;
}
case DIVU: {
Format(instr, "divu 'rs, 'rt");
break;
}
case JALR: {
Format(instr, "jalr'hint 'rd, 'rs");
break;
}
case JR: {
Format(instr, "jr'hint 'rs");
break;
}
case MFHI: {
Format(instr, "mfhi 'rd");
break;
}
case MFLO: {
Format(instr, "mflo 'rd");
break;
}
case MOVCI: {
if (instr->Bit(16)) {
Format(instr, "movt 'rd, 'rs");
} else {
Format(instr, "movf 'rd, 'rs");
}
break;
}
case MOVN: {
Format(instr, "movn 'rd, 'rs, 'rt");
break;
}
case MOVZ: {
Format(instr, "movz 'rd, 'rs, 'rt");
break;
}
case MTHI: {
Format(instr, "mthi 'rs");
break;
}
case MTLO: {
Format(instr, "mtlo 'rs");
break;
}
case MULT: {
Format(instr, "mult 'rs, 'rt");
break;
}
case MULTU: {
Format(instr, "multu 'rs, 'rt");
break;
}
case NOR: {
Format(instr, "nor 'rd, 'rs, 'rt");
break;
}
case OR: {
if (instr->RsField() == 0 && instr->RtField() == 0) {
Format(instr, "mov 'rd, 0");
} else if (instr->RsField() == R0) {
Format(instr, "mov 'rd, 'rt");
} else if (instr->RtField() == R0) {
Format(instr, "mov 'rd, 'rs");
} else {
Format(instr, "or 'rd, 'rs, 'rt");
}
break;
}
case SLL: {
if ((instr->RdField() == R0) &&
(instr->RtField() == R0) &&
(instr->SaField() == 0)) {
Format(instr, "nop");
} else {
Format(instr, "sll 'rd, 'rt, 'sa");
}
break;
}
case SLLV: {
Format(instr, "sllv 'rd, 'rt, 'rs");
break;
}
case SLT: {
Format(instr, "slt 'rd, 'rs, 'rt");
break;
}
case SLTU: {
Format(instr, "sltu 'rd, 'rs, 'rt");
break;
}
case SRA: {
if (instr->RsField() == 0) {
Format(instr, "sra 'rd, 'rt, 'sa");
} else {
Unknown(instr);
}
break;
}
case SRAV: {
Format(instr, "srav 'rd, 'rt, 'rs");
break;
}
case SRL: {
if (instr->RsField() == 0) {
Format(instr, "srl 'rd, 'rt, 'sa");
} else {
Unknown(instr);
}
break;
}
case SRLV: {
if (instr->SaField() == 0) {
Format(instr, "srlv 'rd, 'rt, 'rs");
} else {
Unknown(instr);
}
break;
}
case SUBU: {
Format(instr, "subu 'rd, 'rs, 'rt");
break;
}
case XOR: {
Format(instr, "xor 'rd, 'rs, 'rt");
break;
}
default: {
Unknown(instr);
break;
}
}
}
void MIPSDecoder::DecodeSpecial2(Instr* instr) {
ASSERT(instr->OpcodeField() == SPECIAL2);
switch (instr->FunctionField()) {
case MADD: {
Format(instr, "madd 'rs, 'rt");
break;
}
case MADDU: {
Format(instr, "maddu 'rs, 'rt");
break;
}
case CLO: {
Format(instr, "clo 'rd, 'rs");
break;
}
case CLZ: {
Format(instr, "clz 'rd, 'rs");
break;
}
default: {
Unknown(instr);
break;
}
}
}
void MIPSDecoder::DecodeRegImm(Instr* instr) {
ASSERT(instr->OpcodeField() == REGIMM);
switch (instr->RegImmFnField()) {
case BGEZ: {
Format(instr, "bgez 'rs, 'dest");
break;
}
case BGEZAL: {
Format(instr, "bgezal 'rs, 'dest");
break;
}
case BLTZAL: {
Format(instr, "bltzal 'rs, 'dest");
break;
}
case BGEZL: {
Format(instr, "bgezl 'rs, 'dest");
break;
}
case BLTZ: {
Format(instr, "bltz 'rs, 'dest");
break;
}
case BLTZL: {
Format(instr, "bltzl 'rs, 'dest");
break;
}
default: {
Unknown(instr);
break;
}
}
}
void MIPSDecoder::DecodeCop1(Instr* instr) {
ASSERT(instr->OpcodeField() == COP1);
if (instr->HasFormat()) {
// If the rs field is a valid format, then the function field identifies
// the instruction.
switch (instr->Cop1FunctionField()) {
case COP1_ADD: {
Format(instr, "add.'fmt 'fd, 'fs, 'ft");
break;
}
case COP1_SUB: {
Format(instr, "sub.'fmt 'fd, 'fs, 'ft");
break;
}
case COP1_MUL: {
Format(instr, "mul.'fmt 'fd, 'fs, 'ft");
break;
}
case COP1_DIV: {
Format(instr, "div.'fmt 'fd, 'fs, 'ft");
break;
}
case COP1_SQRT: {
Format(instr, "sqrt.'fmt 'fd, 'fs");
break;
}
case COP1_MOV: {
Format(instr, "mov.'fmt 'fd, 'fs");
break;
}
case COP1_NEG: {
Format(instr, "neg.'fmt 'fd, 'fs");
break;
}
case COP1_C_F: {
Format(instr, "c.f.'fmt 'fs, 'ft");
break;
}
case COP1_C_UN: {
Format(instr, "c.un.'fmt 'fs, 'ft");
break;
}
case COP1_C_EQ: {
Format(instr, "c.eq.'fmt 'fs, 'ft");
break;
}
case COP1_C_UEQ: {
Format(instr, "c.ueq.'fmt 'fs, 'ft");
break;
}
case COP1_C_OLT: {
Format(instr, "c.olt.'fmt 'fs, 'ft");
break;
}
case COP1_C_ULT: {
Format(instr, "c.ult.'fmt 'fs, 'ft");
break;
}
case COP1_C_OLE: {
Format(instr, "c.ole.'fmt 'fs, 'ft");
break;
}
case COP1_C_ULE: {
Format(instr, "c.ule.'fmt 'fs, 'ft");
break;
}
case COP1_CVT_D: {
Format(instr, "cvt.d.'fmt 'fd, 'fs");
break;
}
case COP1_CVT_W: {
Format(instr, "cvt.w.'fmt 'fd, 'fs");
break;
}
default: {
Unknown(instr);
break;
}
}
} else {
// If the rs field isn't a valid format, then it must be a sub-opcode.
switch (instr->Cop1SubField()) {
case COP1_MF: {
if (instr->Bits(0, 11) != 0) {
Unknown(instr);
} else {
Format(instr, "mfc1 'rt, 'fs");
}
break;
}
case COP1_MT: {
if (instr->Bits(0, 11) != 0) {
Unknown(instr);
} else {
Format(instr, "mtc1 'rt, 'fs");
}
break;
}
case COP1_BC: {
ASSERT(instr->Bit(17) == 0);
if (instr->Bit(16) == 1) { // Branch on true.
Format(instr, "bc1t 'dest");
} else { // Branch on false.
Format(instr, "bc1f 'dest");
}
break;
}
default: {
Unknown(instr);
break;
}
}
}
}
void MIPSDecoder::InstructionDecode(Instr* instr) {
switch (instr->OpcodeField()) {
case SPECIAL: {
DecodeSpecial(instr);
break;
}
case SPECIAL2: {
DecodeSpecial2(instr);
break;
}
case REGIMM: {
DecodeRegImm(instr);
break;
}
case COP1: {
DecodeCop1(instr);
break;
}
case ADDIU: {
Format(instr, "addiu 'rt, 'rs, 'imms");
break;
}
case ANDI: {
Format(instr, "andi 'rt, 'rs, 'immu");
break;
}
case BEQ: {
Format(instr, "beq 'rs, 'rt, 'dest");
break;
}
case BEQL: {
Format(instr, "beql 'rs, 'rt, 'dest");
break;
}
case BGTZ: {
Format(instr, "bgtz 'rs, 'dest");
break;
}
case BGTZL: {
Format(instr, "bgtzl 'rs, 'dest");
break;
}
case BLEZ: {
Format(instr, "blez 'rs, 'dest");
break;
}
case BLEZL: {
Format(instr, "blezl 'rs, 'dest");
break;
}
case BNE: {
Format(instr, "bne 'rs, 'rt, 'dest");
break;
}
case BNEL: {
Format(instr, "bnel 'rs, 'rt, 'dest");
break;
}
case LB: {
Format(instr, "lb 'rt, 'imms('rs)");
break;
}
case LBU: {
Format(instr, "lbu 'rt, 'imms('rs)");
break;
}
case LDC1: {
Format(instr, "ldc1 'ft, 'imms('rs)");
break;
}
case LH: {
Format(instr, "lh 'rt, 'imms('rs)");
break;
}
case LHU: {
Format(instr, "lhu 'rt, 'imms('rs)");
break;
}
case LUI: {
Format(instr, "lui 'rt, 'immu");
break;
}
case LW: {
Format(instr, "lw 'rt, 'imms('rs)");
break;
}
case LWC1: {
Format(instr, "lwc1 'ft, 'imms('rs)");
break;
}
case ORI: {
Format(instr, "ori 'rt, 'rs, 'immu");
break;
}
case SB: {
Format(instr, "sb 'rt, 'imms('rs)");
break;
}
case SLTI: {
Format(instr, "slti 'rt, 'rs, 'imms");
break;
}
case SLTIU: {
Format(instr, "sltiu 'rt, 'rs, 'imms");
break;
}
case SH: {
Format(instr, "sh 'rt, 'imms('rs)");
break;
}
case SDC1: {
Format(instr, "sdc1 'ft, 'imms('rs)");
break;
}
case SW: {
Format(instr, "sw 'rt, 'imms('rs)");
break;
}
case SWC1: {
Format(instr, "swc1 'ft, 'imms('rs)");
break;
}
case XORI: {
Format(instr, "xori 'rt, 'rs, 'immu");
break;
}
default: {
Unknown(instr);
break;
}
}
}
void Disassembler::DecodeInstruction(char* hex_buffer, intptr_t hex_size,
char* human_buffer, intptr_t human_size,
int* out_instr_len, uword pc) {
MIPSDecoder decoder(human_buffer, human_size);
Instr* instr = Instr::At(pc);
decoder.InstructionDecode(instr);
OS::SNPrint(hex_buffer, hex_size, "%08x", instr->InstructionBits());
if (out_instr_len) {
*out_instr_len = Instr::kInstrSize;
}
}
} // namespace dart
#endif // defined TARGET_ARCH_MIPS