suyu/src/core/arm/disassembler/arm_disasm.cpp

966 lines
No EOL
25 KiB
C++

// Copyright 2006 The Android Open Source Project
#include <string>
#include "common/string_util.h"
#include "core/arm/disassembler/arm_disasm.h"
static const char *cond_names[] = {
"eq",
"ne",
"cs",
"cc",
"mi",
"pl",
"vs",
"vc",
"hi",
"ls",
"ge",
"lt",
"gt",
"le",
"",
"RESERVED"
};
const char *opcode_names[] = {
"invalid",
"undefined",
"adc",
"add",
"and",
"b",
"bl",
"bic",
"bkpt",
"blx",
"bx",
"cdp",
"clz",
"cmn",
"cmp",
"eor",
"ldc",
"ldm",
"ldr",
"ldrb",
"ldrbt",
"ldrh",
"ldrsb",
"ldrsh",
"ldrt",
"mcr",
"mla",
"mov",
"mrc",
"mrs",
"msr",
"mul",
"mvn",
"orr",
"pld",
"rsb",
"rsc",
"sbc",
"smlal",
"smull",
"stc",
"stm",
"str",
"strb",
"strbt",
"strh",
"strt",
"sub",
"swi",
"swp",
"swpb",
"teq",
"tst",
"umlal",
"umull",
"undefined",
"adc",
"add",
"and",
"asr",
"b",
"bic",
"bkpt",
"bl",
"blx",
"bx",
"cmn",
"cmp",
"eor",
"ldmia",
"ldr",
"ldrb",
"ldrh",
"ldrsb",
"ldrsh",
"lsl",
"lsr",
"mov",
"mul",
"mvn",
"neg",
"orr",
"pop",
"push",
"ror",
"sbc",
"stmia",
"str",
"strb",
"strh",
"sub",
"swi",
"tst",
NULL
};
// Indexed by the shift type (bits 6-5)
static const char *shift_names[] = {
"LSL",
"LSR",
"ASR",
"ROR"
};
static const char* cond_to_str(int cond) {
return cond_names[cond];
}
std::string ARM_Disasm::Disassemble(uint32_t addr, uint32_t insn)
{
Opcode opcode = Decode(insn);
switch (opcode) {
case OP_INVALID:
return "Invalid";
case OP_UNDEFINED:
return "Undefined";
case OP_ADC:
case OP_ADD:
case OP_AND:
case OP_BIC:
case OP_CMN:
case OP_CMP:
case OP_EOR:
case OP_MOV:
case OP_MVN:
case OP_ORR:
case OP_RSB:
case OP_RSC:
case OP_SBC:
case OP_SUB:
case OP_TEQ:
case OP_TST:
return DisassembleALU(opcode, insn);
case OP_B:
case OP_BL:
return DisassembleBranch(addr, opcode, insn);
case OP_BKPT:
return DisassembleBKPT(insn);
case OP_BLX:
// not supported yet
break;
case OP_BX:
return DisassembleBX(insn);
case OP_CDP:
return "cdp";
case OP_CLZ:
return DisassembleCLZ(insn);
case OP_LDC:
return "ldc";
case OP_LDM:
case OP_STM:
return DisassembleMemblock(opcode, insn);
case OP_LDR:
case OP_LDRB:
case OP_LDRBT:
case OP_LDRT:
case OP_STR:
case OP_STRB:
case OP_STRBT:
case OP_STRT:
return DisassembleMem(insn);
case OP_LDRH:
case OP_LDRSB:
case OP_LDRSH:
case OP_STRH:
return DisassembleMemHalf(insn);
case OP_MCR:
case OP_MRC:
return DisassembleMCR(opcode, insn);
case OP_MLA:
return DisassembleMLA(opcode, insn);
case OP_MRS:
return DisassembleMRS(insn);
case OP_MSR:
return DisassembleMSR(insn);
case OP_MUL:
return DisassembleMUL(opcode, insn);
case OP_PLD:
return DisassemblePLD(insn);
case OP_STC:
return "stc";
case OP_SWI:
return DisassembleSWI(insn);
case OP_SWP:
case OP_SWPB:
return DisassembleSWP(opcode, insn);
case OP_UMLAL:
case OP_UMULL:
case OP_SMLAL:
case OP_SMULL:
return DisassembleUMLAL(opcode, insn);
default:
return "Error";
}
return NULL;
}
std::string ARM_Disasm::DisassembleALU(Opcode opcode, uint32_t insn)
{
static const uint8_t kNoOperand1 = 1;
static const uint8_t kNoDest = 2;
static const uint8_t kNoSbit = 4;
std::string rn_str;
std::string rd_str;
uint8_t flags = 0;
uint8_t cond = (insn >> 28) & 0xf;
uint8_t is_immed = (insn >> 25) & 0x1;
uint8_t bit_s = (insn >> 20) & 1;
uint8_t rn = (insn >> 16) & 0xf;
uint8_t rd = (insn >> 12) & 0xf;
uint8_t immed = insn & 0xff;
const char* opname = opcode_names[opcode];
switch (opcode) {
case OP_CMN:
case OP_CMP:
case OP_TEQ:
case OP_TST:
flags = kNoDest | kNoSbit;
break;
case OP_MOV:
case OP_MVN:
flags = kNoOperand1;
break;
default:
break;
}
// The "mov" instruction ignores the first operand (rn).
rn_str[0] = 0;
if ((flags & kNoOperand1) == 0) {
rn_str = StringFromFormat("r%d, ", rn);
}
// The following instructions do not write the result register (rd):
// tst, teq, cmp, cmn.
rd_str[0] = 0;
if ((flags & kNoDest) == 0) {
rd_str = StringFromFormat("r%d, ", rd);
}
const char *sbit_str = "";
if (bit_s && !(flags & kNoSbit))
sbit_str = "s";
if (is_immed) {
return StringFromFormat("%s%s%s\t%s%s#%u ; 0x%x",
opname, cond_to_str(cond), sbit_str, rd_str.c_str(), rn_str.c_str(), immed, immed);
}
uint8_t shift_is_reg = (insn >> 4) & 1;
uint8_t rotate = (insn >> 8) & 0xf;
uint8_t rm = insn & 0xf;
uint8_t shift_type = (insn >> 5) & 0x3;
uint8_t rs = (insn >> 8) & 0xf;
uint8_t shift_amount = (insn >> 7) & 0x1f;
uint32_t rotated_val = immed;
uint8_t rotate2 = rotate << 1;
rotated_val = (rotated_val >> rotate2) | (rotated_val << (32 - rotate2));
if (!shift_is_reg && shift_type == 0 && shift_amount == 0) {
return StringFromFormat("%s%s%s\t%s%sr%d",
opname, cond_to_str(cond), sbit_str, rd_str.c_str(), rn_str.c_str(), rm);
}
const char *shift_name = shift_names[shift_type];
if (shift_is_reg) {
return StringFromFormat("%s%s%s\t%s%sr%d, %s r%d",
opname, cond_to_str(cond), sbit_str, rd_str.c_str(), rn_str.c_str(), rm,
shift_name, rs);
}
if (shift_amount == 0) {
if (shift_type == 3) {
return StringFromFormat("%s%s%s\t%s%sr%d, RRX",
opname, cond_to_str(cond), sbit_str, rd_str.c_str(), rn_str.c_str(), rm);
}
shift_amount = 32;
}
return StringFromFormat("%s%s%s\t%s%sr%d, %s #%u",
opname, cond_to_str(cond), sbit_str, rd_str.c_str(), rn_str.c_str(), rm,
shift_name, shift_amount);
}
std::string ARM_Disasm::DisassembleBranch(uint32_t addr, Opcode opcode, uint32_t insn)
{
uint8_t cond = (insn >> 28) & 0xf;
uint32_t offset = insn & 0xffffff;
// Sign-extend the 24-bit offset
if ((offset >> 23) & 1)
offset |= 0xff000000;
// Pre-compute the left-shift and the prefetch offset
offset <<= 2;
offset += 8;
addr += offset;
const char *opname = opcode_names[opcode];
return StringFromFormat("%s%s\t0x%x", opname, cond_to_str(cond), addr);
}
std::string ARM_Disasm::DisassembleBX(uint32_t insn)
{
uint8_t cond = (insn >> 28) & 0xf;
uint8_t rn = insn & 0xf;
return StringFromFormat("bx%s\tr%d", cond_to_str(cond), rn);
}
std::string ARM_Disasm::DisassembleBKPT(uint32_t insn)
{
uint32_t immed = (((insn >> 8) & 0xfff) << 4) | (insn & 0xf);
return StringFromFormat("bkpt\t#%d", immed);
}
std::string ARM_Disasm::DisassembleCLZ(uint32_t insn)
{
uint8_t cond = (insn >> 28) & 0xf;
uint8_t rd = (insn >> 12) & 0xf;
uint8_t rm = insn & 0xf;
return StringFromFormat("clz%s\tr%d, r%d", cond_to_str(cond), rd, rm);
}
std::string ARM_Disasm::DisassembleMemblock(Opcode opcode, uint32_t insn)
{
std::string tmp_reg;
std::string tmp_list;
uint8_t cond = (insn >> 28) & 0xf;
uint8_t write_back = (insn >> 21) & 0x1;
uint8_t bit_s = (insn >> 22) & 0x1;
uint8_t is_up = (insn >> 23) & 0x1;
uint8_t is_pre = (insn >> 24) & 0x1;
uint8_t rn = (insn >> 16) & 0xf;
uint16_t reg_list = insn & 0xffff;
const char *opname = opcode_names[opcode];
const char *bang = "";
if (write_back)
bang = "!";
const char *carret = "";
if (bit_s)
carret = "^";
const char *comma = "";
tmp_list[0] = 0;
for (int ii = 0; ii < 16; ++ii) {
if (reg_list & (1 << ii)) {
tmp_list += StringFromFormat("%sr%d", comma, ii);
comma = ",";
}
}
const char *addr_mode = "";
if (is_pre) {
if (is_up) {
addr_mode = "ib";
} else {
addr_mode = "db";
}
} else {
if (is_up) {
addr_mode = "ia";
} else {
addr_mode = "da";
}
}
return StringFromFormat("%s%s%s\tr%d%s, {%s}%s",
opname, cond_to_str(cond), addr_mode, rn, bang, tmp_list.c_str(), carret);
}
std::string ARM_Disasm::DisassembleMem(uint32_t insn)
{
uint8_t cond = (insn >> 28) & 0xf;
uint8_t is_reg = (insn >> 25) & 0x1;
uint8_t is_load = (insn >> 20) & 0x1;
uint8_t write_back = (insn >> 21) & 0x1;
uint8_t is_byte = (insn >> 22) & 0x1;
uint8_t is_up = (insn >> 23) & 0x1;
uint8_t is_pre = (insn >> 24) & 0x1;
uint8_t rn = (insn >> 16) & 0xf;
uint8_t rd = (insn >> 12) & 0xf;
uint16_t offset = insn & 0xfff;
const char *opname = "ldr";
if (!is_load)
opname = "str";
const char *bang = "";
if (write_back)
bang = "!";
const char *minus = "";
if (is_up == 0)
minus = "-";
const char *byte = "";
if (is_byte)
byte = "b";
if (is_reg == 0) {
if (is_pre) {
if (offset == 0) {
return StringFromFormat("%s%s%s\tr%d, [r%d]",
opname, cond_to_str(cond), byte, rd, rn);
} else {
return StringFromFormat("%s%s%s\tr%d, [r%d, #%s%u]%s",
opname, cond_to_str(cond), byte, rd, rn, minus, offset, bang);
}
} else {
const char *transfer = "";
if (write_back)
transfer = "t";
return StringFromFormat("%s%s%s%s\tr%d, [r%d], #%s%u",
opname, cond_to_str(cond), byte, transfer, rd, rn, minus, offset);
}
}
uint8_t rm = insn & 0xf;
uint8_t shift_type = (insn >> 5) & 0x3;
uint8_t shift_amount = (insn >> 7) & 0x1f;
const char *shift_name = shift_names[shift_type];
if (is_pre) {
if (shift_amount == 0) {
if (shift_type == 0) {
return StringFromFormat("%s%s%s\tr%d, [r%d, %sr%d]%s",
opname, cond_to_str(cond), byte, rd, rn, minus, rm, bang);
}
if (shift_type == 3) {
return StringFromFormat("%s%s%s\tr%d, [r%d, %sr%d, RRX]%s",
opname, cond_to_str(cond), byte, rd, rn, minus, rm, bang);
}
shift_amount = 32;
}
return StringFromFormat("%s%s%s\tr%d, [r%d, %sr%d, %s #%u]%s",
opname, cond_to_str(cond), byte, rd, rn, minus, rm,
shift_name, shift_amount, bang);
}
const char *transfer = "";
if (write_back)
transfer = "t";
if (shift_amount == 0) {
if (shift_type == 0) {
return StringFromFormat("%s%s%s%s\tr%d, [r%d], %sr%d",
opname, cond_to_str(cond), byte, transfer, rd, rn, minus, rm);
}
if (shift_type == 3) {
return StringFromFormat("%s%s%s%s\tr%d, [r%d], %sr%d, RRX",
opname, cond_to_str(cond), byte, transfer, rd, rn, minus, rm);
}
shift_amount = 32;
}
return StringFromFormat("%s%s%s%s\tr%d, [r%d], %sr%d, %s #%u",
opname, cond_to_str(cond), byte, transfer, rd, rn, minus, rm,
shift_name, shift_amount);
}
std::string ARM_Disasm::DisassembleMemHalf(uint32_t insn)
{
uint8_t cond = (insn >> 28) & 0xf;
uint8_t is_load = (insn >> 20) & 0x1;
uint8_t write_back = (insn >> 21) & 0x1;
uint8_t is_immed = (insn >> 22) & 0x1;
uint8_t is_up = (insn >> 23) & 0x1;
uint8_t is_pre = (insn >> 24) & 0x1;
uint8_t rn = (insn >> 16) & 0xf;
uint8_t rd = (insn >> 12) & 0xf;
uint8_t bits_65 = (insn >> 5) & 0x3;
uint8_t rm = insn & 0xf;
uint8_t offset = (((insn >> 8) & 0xf) << 4) | (insn & 0xf);
const char *opname = "ldr";
if (is_load == 0)
opname = "str";
const char *width = "";
if (bits_65 == 1)
width = "h";
else if (bits_65 == 2)
width = "sb";
else
width = "sh";
const char *bang = "";
if (write_back)
bang = "!";
const char *minus = "";
if (is_up == 0)
minus = "-";
if (is_immed) {
if (is_pre) {
if (offset == 0) {
return StringFromFormat("%s%sh\tr%d, [r%d]", opname, cond_to_str(cond), rd, rn);
} else {
return StringFromFormat("%s%sh\tr%d, [r%d, #%s%u]%s",
opname, cond_to_str(cond), rd, rn, minus, offset, bang);
}
} else {
return StringFromFormat("%s%sh\tr%d, [r%d], #%s%u",
opname, cond_to_str(cond), rd, rn, minus, offset);
}
}
if (is_pre) {
return StringFromFormat("%s%sh\tr%d, [r%d, %sr%d]%s",
opname, cond_to_str(cond), rd, rn, minus, rm, bang);
} else {
return StringFromFormat("%s%sh\tr%d, [r%d], %sr%d",
opname, cond_to_str(cond), rd, rn, minus, rm);
}
}
std::string ARM_Disasm::DisassembleMCR(Opcode opcode, uint32_t insn)
{
uint8_t cond = (insn >> 28) & 0xf;
uint8_t crn = (insn >> 16) & 0xf;
uint8_t crd = (insn >> 12) & 0xf;
uint8_t cpnum = (insn >> 8) & 0xf;
uint8_t opcode2 = (insn >> 5) & 0x7;
uint8_t crm = insn & 0xf;
const char *opname = opcode_names[opcode];
return StringFromFormat("%s%s\t%d, 0, r%d, cr%d, cr%d, {%d}",
opname, cond_to_str(cond), cpnum, crd, crn, crm, opcode2);
}
std::string ARM_Disasm::DisassembleMLA(Opcode opcode, uint32_t insn)
{
uint8_t cond = (insn >> 28) & 0xf;
uint8_t rd = (insn >> 16) & 0xf;
uint8_t rn = (insn >> 12) & 0xf;
uint8_t rs = (insn >> 8) & 0xf;
uint8_t rm = insn & 0xf;
uint8_t bit_s = (insn >> 20) & 1;
const char *opname = opcode_names[opcode];
return StringFromFormat("%s%s%s\tr%d, r%d, r%d, r%d",
opname, cond_to_str(cond), bit_s ? "s" : "", rd, rm, rs, rn);
}
std::string ARM_Disasm::DisassembleUMLAL(Opcode opcode, uint32_t insn)
{
uint8_t cond = (insn >> 28) & 0xf;
uint8_t rdhi = (insn >> 16) & 0xf;
uint8_t rdlo = (insn >> 12) & 0xf;
uint8_t rs = (insn >> 8) & 0xf;
uint8_t rm = insn & 0xf;
uint8_t bit_s = (insn >> 20) & 1;
const char *opname = opcode_names[opcode];
return StringFromFormat("%s%s%s\tr%d, r%d, r%d, r%d",
opname, cond_to_str(cond), bit_s ? "s" : "", rdlo, rdhi, rm, rs);
}
std::string ARM_Disasm::DisassembleMUL(Opcode opcode, uint32_t insn)
{
uint8_t cond = (insn >> 28) & 0xf;
uint8_t rd = (insn >> 16) & 0xf;
uint8_t rs = (insn >> 8) & 0xf;
uint8_t rm = insn & 0xf;
uint8_t bit_s = (insn >> 20) & 1;
const char *opname = opcode_names[opcode];
return StringFromFormat("%s%s%s\tr%d, r%d, r%d",
opname, cond_to_str(cond), bit_s ? "s" : "", rd, rm, rs);
}
std::string ARM_Disasm::DisassembleMRS(uint32_t insn)
{
uint8_t cond = (insn >> 28) & 0xf;
uint8_t rd = (insn >> 12) & 0xf;
uint8_t ps = (insn >> 22) & 1;
return StringFromFormat("mrs%s\tr%d, %s", cond_to_str(cond), rd, ps ? "spsr" : "cpsr");
}
std::string ARM_Disasm::DisassembleMSR(uint32_t insn)
{
char flags[8];
int flag_index = 0;
uint8_t cond = (insn >> 28) & 0xf;
uint8_t is_immed = (insn >> 25) & 0x1;
uint8_t pd = (insn >> 22) & 1;
uint8_t mask = (insn >> 16) & 0xf;
if (mask & 1)
flags[flag_index++] = 'c';
if (mask & 2)
flags[flag_index++] = 'x';
if (mask & 4)
flags[flag_index++] = 's';
if (mask & 8)
flags[flag_index++] = 'f';
flags[flag_index] = 0;
if (is_immed) {
uint32_t immed = insn & 0xff;
uint8_t rotate = (insn >> 8) & 0xf;
uint8_t rotate2 = rotate << 1;
uint32_t rotated_val = (immed >> rotate2) | (immed << (32 - rotate2));
return StringFromFormat("msr%s\t%s_%s, #0x%x",
cond_to_str(cond), pd ? "spsr" : "cpsr", flags, rotated_val);
}
uint8_t rm = insn & 0xf;
return StringFromFormat("msr%s\t%s_%s, r%d",
cond_to_str(cond), pd ? "spsr" : "cpsr", flags, rm);
}
std::string ARM_Disasm::DisassemblePLD(uint32_t insn)
{
uint8_t is_reg = (insn >> 25) & 0x1;
uint8_t is_up = (insn >> 23) & 0x1;
uint8_t rn = (insn >> 16) & 0xf;
const char *minus = "";
if (is_up == 0)
minus = "-";
if (is_reg) {
uint8_t rm = insn & 0xf;
return StringFromFormat("pld\t[r%d, %sr%d]", rn, minus, rm);
}
uint16_t offset = insn & 0xfff;
if (offset == 0) {
return StringFromFormat("pld\t[r%d]", rn);
} else {
return StringFromFormat("pld\t[r%d, #%s%u]", rn, minus, offset);
}
}
std::string ARM_Disasm::DisassembleSWI(uint32_t insn)
{
uint8_t cond = (insn >> 28) & 0xf;
uint32_t sysnum = insn & 0x00ffffff;
return StringFromFormat("swi%s 0x%x", cond_to_str(cond), sysnum);
}
std::string ARM_Disasm::DisassembleSWP(Opcode opcode, uint32_t insn)
{
uint8_t cond = (insn >> 28) & 0xf;
uint8_t rn = (insn >> 16) & 0xf;
uint8_t rd = (insn >> 12) & 0xf;
uint8_t rm = insn & 0xf;
const char *opname = opcode_names[opcode];
return StringFromFormat("%s%s\tr%d, r%d, [r%d]", opname, cond_to_str(cond), rd, rm, rn);
}
Opcode ARM_Disasm::Decode(uint32_t insn) {
uint32_t bits27_26 = (insn >> 26) & 0x3;
switch (bits27_26) {
case 0x0:
return Decode00(insn);
case 0x1:
return Decode01(insn);
case 0x2:
return Decode10(insn);
case 0x3:
return Decode11(insn);
}
return OP_INVALID;
}
Opcode ARM_Disasm::Decode00(uint32_t insn) {
uint8_t bit25 = (insn >> 25) & 0x1;
uint8_t bit4 = (insn >> 4) & 0x1;
if (bit25 == 0 && bit4 == 1) {
if ((insn & 0x0ffffff0) == 0x012fff10) {
// Bx instruction
return OP_BX;
}
if ((insn & 0x0ff000f0) == 0x01600010) {
// Clz instruction
return OP_CLZ;
}
if ((insn & 0xfff000f0) == 0xe1200070) {
// Bkpt instruction
return OP_BKPT;
}
uint32_t bits7_4 = (insn >> 4) & 0xf;
if (bits7_4 == 0x9) {
if ((insn & 0x0ff00ff0) == 0x01000090) {
// Swp instruction
uint8_t bit22 = (insn >> 22) & 0x1;
if (bit22)
return OP_SWPB;
return OP_SWP;
}
// One of the multiply instructions
return DecodeMUL(insn);
}
uint8_t bit7 = (insn >> 7) & 0x1;
if (bit7 == 1) {
// One of the load/store halfword/byte instructions
return DecodeLDRH(insn);
}
}
// One of the data processing instructions
return DecodeALU(insn);
}
Opcode ARM_Disasm::Decode01(uint32_t insn) {
uint8_t is_reg = (insn >> 25) & 0x1;
uint8_t bit4 = (insn >> 4) & 0x1;
if (is_reg == 1 && bit4 == 1)
return OP_UNDEFINED;
uint8_t is_load = (insn >> 20) & 0x1;
uint8_t is_byte = (insn >> 22) & 0x1;
if ((insn & 0xfd70f000) == 0xf550f000) {
// Pre-load
return OP_PLD;
}
if (is_load) {
if (is_byte) {
// Load byte
return OP_LDRB;
}
// Load word
return OP_LDR;
}
if (is_byte) {
// Store byte
return OP_STRB;
}
// Store word
return OP_STR;
}
Opcode ARM_Disasm::Decode10(uint32_t insn) {
uint8_t bit25 = (insn >> 25) & 0x1;
if (bit25 == 0) {
// LDM/STM
uint8_t is_load = (insn >> 20) & 0x1;
if (is_load)
return OP_LDM;
return OP_STM;
}
// Branch or Branch with link
uint8_t is_link = (insn >> 24) & 1;
uint32_t offset = insn & 0xffffff;
// Sign-extend the 24-bit offset
if ((offset >> 23) & 1)
offset |= 0xff000000;
// Pre-compute the left-shift and the prefetch offset
offset <<= 2;
offset += 8;
if (is_link == 0)
return OP_B;
return OP_BL;
}
Opcode ARM_Disasm::Decode11(uint32_t insn) {
uint8_t bit25 = (insn >> 25) & 0x1;
if (bit25 == 0) {
// LDC, SDC
uint8_t is_load = (insn >> 20) & 0x1;
if (is_load) {
// LDC
return OP_LDC;
}
// STC
return OP_STC;
}
uint8_t bit24 = (insn >> 24) & 0x1;
if (bit24 == 0x1) {
// SWI
return OP_SWI;
}
uint8_t bit4 = (insn >> 4) & 0x1;
uint8_t cpnum = (insn >> 8) & 0xf;
if (cpnum == 15) {
// Special case for coprocessor 15
uint8_t opcode = (insn >> 21) & 0x7;
if (bit4 == 0 || opcode != 0) {
// This is an unexpected bit pattern. Create an undefined
// instruction in case this is ever executed.
return OP_UNDEFINED;
}
// MRC, MCR
uint8_t is_mrc = (insn >> 20) & 0x1;
if (is_mrc)
return OP_MRC;
return OP_MCR;
}
if (bit4 == 0) {
// CDP
return OP_CDP;
}
// MRC, MCR
uint8_t is_mrc = (insn >> 20) & 0x1;
if (is_mrc)
return OP_MRC;
return OP_MCR;
}
Opcode ARM_Disasm::DecodeMUL(uint32_t insn) {
uint8_t bit24 = (insn >> 24) & 0x1;
if (bit24 != 0) {
// This is an unexpected bit pattern. Create an undefined
// instruction in case this is ever executed.
return OP_UNDEFINED;
}
uint8_t bit23 = (insn >> 23) & 0x1;
uint8_t bit22_U = (insn >> 22) & 0x1;
uint8_t bit21_A = (insn >> 21) & 0x1;
if (bit23 == 0) {
// 32-bit multiply
if (bit22_U != 0) {
// This is an unexpected bit pattern. Create an undefined
// instruction in case this is ever executed.
return OP_UNDEFINED;
}
if (bit21_A == 0)
return OP_MUL;
return OP_MLA;
}
// 64-bit multiply
if (bit22_U == 0) {
// Unsigned multiply long
if (bit21_A == 0)
return OP_UMULL;
return OP_UMLAL;
}
// Signed multiply long
if (bit21_A == 0)
return OP_SMULL;
return OP_SMLAL;
}
Opcode ARM_Disasm::DecodeLDRH(uint32_t insn) {
uint8_t is_load = (insn >> 20) & 0x1;
uint8_t bits_65 = (insn >> 5) & 0x3;
if (is_load) {
if (bits_65 == 0x1) {
// Load unsigned halfword
return OP_LDRH;
} else if (bits_65 == 0x2) {
// Load signed byte
return OP_LDRSB;
}
// Signed halfword
if (bits_65 != 0x3) {
// This is an unexpected bit pattern. Create an undefined
// instruction in case this is ever executed.
return OP_UNDEFINED;
}
// Load signed halfword
return OP_LDRSH;
}
// Store halfword
if (bits_65 != 0x1) {
// This is an unexpected bit pattern. Create an undefined
// instruction in case this is ever executed.
return OP_UNDEFINED;
}
// Store halfword
return OP_STRH;
}
Opcode ARM_Disasm::DecodeALU(uint32_t insn) {
uint8_t is_immed = (insn >> 25) & 0x1;
uint8_t opcode = (insn >> 21) & 0xf;
uint8_t bit_s = (insn >> 20) & 1;
uint8_t shift_is_reg = (insn >> 4) & 1;
uint8_t bit7 = (insn >> 7) & 1;
if (!is_immed && shift_is_reg && (bit7 != 0)) {
// This is an unexpected bit pattern. Create an undefined
// instruction in case this is ever executed.
return OP_UNDEFINED;
}
switch (opcode) {
case 0x0:
return OP_AND;
case 0x1:
return OP_EOR;
case 0x2:
return OP_SUB;
case 0x3:
return OP_RSB;
case 0x4:
return OP_ADD;
case 0x5:
return OP_ADC;
case 0x6:
return OP_SBC;
case 0x7:
return OP_RSC;
case 0x8:
if (bit_s)
return OP_TST;
return OP_MRS;
case 0x9:
if (bit_s)
return OP_TEQ;
return OP_MSR;
case 0xa:
if (bit_s)
return OP_CMP;
return OP_MRS;
case 0xb:
if (bit_s)
return OP_CMN;
return OP_MSR;
case 0xc:
return OP_ORR;
case 0xd:
return OP_MOV;
case 0xe:
return OP_BIC;
case 0xf:
return OP_MVN;
}
// Unreachable
return OP_INVALID;
}