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x86_interpreter.c
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#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include "x86_regs.h"
#include "dynamic_memory.h"
#include "dmem_utils.h"
#include "read_raw.h"
#include "read_elf.h"
#include "read_pe.h"
#include "xv6_syscall.h"
#include "pe_import.h"
static int strict_mode = 0;
static int use_xv6_syscall = 0;
static int use_pe_import = 0;
static pe_import_params import_params;
uint32_t regs[8];
uint32_t eip;
uint32_t eflags;
uint32_t segment_offsets[6];
void print_regs(FILE* fp) {
fprintf(fp, " EAX:%08"PRIx32" EBX:%08"PRIx32" ECX:%08"PRIx32" EDX:%08"PRIx32"\n",
regs[EAX], regs[EBX], regs[ECX], regs[EDX]);
fprintf(fp, " ESI:%08"PRIx32" EDI:%08"PRIx32" ESP:%08"PRIx32" EBP:%08"PRIx32"\n",
regs[ESI], regs[EDI], regs[ESP], regs[EBP]);
fprintf(fp, " EIP:%08"PRIx32"\n", eip);
fprintf(fp, "EFLAGS:%08"PRIx32
" (CF[%c] PF[%c] AF[%c] ZF[%c] SF[%c] IF[%c] DF[%c] OF[%c])\n", eflags,
eflags & CF ? 'x' : ' ', eflags & PF ? 'x' : ' ', eflags & AF ? 'x' : ' ',
eflags & ZF ? 'x' : ' ', eflags & SF ? 'x' : ' ', eflags & IF ? 'x' : ' ',
eflags & DF ? 'x' : ' ', eflags & OF ? 'x' : ' ');
}
int memory_access(uint8_t* data_read, uint32_t addr, uint8_t data, int we) {
if (dmemory_is_allocated(addr, 1)) {
if (we) dmemory_write(&data, addr, 1);
dmemory_read(data_read, addr, 1);
return 1;
} else {
return 0;
}
}
static uint32_t step_memread(int* success, uint32_t inst_addr, int segment, uint32_t addr, int size) {
uint32_t res = 0;
int i;
if (UINT32_MAX - segment_offsets[segment] < addr ||
(size <= 0 || UINT32_MAX - (segment_offsets[segment] + addr) < (uint32_t)(size - 1))) {
*success = 0;
return 0;
}
for (i = 0; i < size; i++) {
uint32_t this_addr = segment_offsets[segment] + addr + i;
uint8_t value;
if (!memory_access(&value, this_addr, 0, 0)) {
fprintf(stderr, "failed to read memory %08"PRIx32" at %08"PRIx32"\n\n", this_addr, inst_addr);
print_regs(stderr);
*success = 0;
return 0;
}
res |= value << (i * 8);
}
if (size < 4) {
if (res & (UINT32_C(0x80) << ((size - 1) * 8))) {
res |= UINT32_C(0xffffffff) << (size * 8);
} else {
res &= UINT32_C(0xffffffff) >> ((4 - size) * 8);
}
}
*success = 1;
return res;
}
static int step_memwrite(uint32_t inst_addr, int segment, uint32_t addr, uint32_t value, int size) {
int i;
if (UINT32_MAX - segment_offsets[segment] < addr ||
(size <= 0 || UINT32_MAX - (segment_offsets[segment] + addr) < (uint32_t)(size - 1))) {
return 0;
}
for (i = 0; i < size; i++) {
uint32_t this_addr = segment_offsets[segment] + addr + i;
uint8_t dummy_read;
if (!memory_access(&dummy_read, this_addr, (value >> (i * 8)) & 0xff, 1)) {
fprintf(stderr, "failed to write memory %08"PRIx32" at %08"PRIx32"\n\n", this_addr, inst_addr);
print_regs(stderr);
return 0;
}
}
return 1;
}
static int step_push(uint32_t inst_addr, uint32_t value, int op_width, int is_addr_16bit) {
uint32_t addr = regs[ESP];
if (is_addr_16bit) addr &= 0xffff;
addr -= op_width;
if (!step_memwrite(inst_addr, SS, addr, value, op_width)) return 0;
if (is_addr_16bit) {
regs[ESP] = (regs[ESP] & UINT32_C(0xffff0000)) | (addr & 0xffff);
} else {
regs[ESP] = addr;
}
return 1;
}
static uint32_t step_pop(int* success, uint32_t inst_addr, int op_width, int is_addr_16bit) {
int memread_ok = 0;
uint32_t next_esp;
uint32_t value = step_memread(&memread_ok, inst_addr, SS,
is_addr_16bit ? regs[ESP] & 0xffff : regs[ESP], op_width);
if (!memread_ok) {
*success = 0;
return 0;
}
next_esp = regs[ESP] + op_width;
if (is_addr_16bit) {
regs[ESP] = (regs[ESP] & UINT32_C(0xffff0000)) | (next_esp & 0xffff);
} else {
regs[ESP] = next_esp;
}
*success = 1;
return value;
}
int step(void) {
uint32_t inst_addr = eip; /* エラー時の検証用 */
uint8_t fetch_data;
int memread_ok;
int is_data_16bit = 0;
int is_addr_16bit = 0;
int is_rep = 0;
int is_rep_while_zero = 0;
enum {
OP_ARITHMETIC,
OP_SHIFT,
OP_XCHG,
OP_CMPXCHG,
OP_MOV,
OP_CMOV,
OP_MOVZX,
OP_MOVSX,
OP_SETCC,
OP_LEA,
OP_INCDEC,
OP_NOT,
OP_MUL,
OP_IMUL,
OP_DIV,
OP_IDIV,
OP_PUSH,
OP_POP,
OP_PUSHA,
OP_POPA,
OP_PUSHF,
OP_POPF,
OP_STRING,
OP_CALL,
OP_JUMP,
OP_CALL_ABSOLUTE,
OP_JUMP_ABSOLUTE,
OP_CALL_FAR,
OP_JUMP_FAR,
OP_CBW,
OP_CWD,
OP_SAHF,
OP_LAHF,
OP_RETN,
OP_LEAVE,
OP_INT,
OP_INTO,
OP_IRET,
OP_LOOP,
OP_IN,
OP_OUT,
OP_HLT,
OP_CMC,
OP_SET_FLAG,
OP_CLEAR_FLAG,
OP_FPU,
} op_kind = OP_ARITHMETIC; /* 命令の種類 */
enum {
OP_ADD, OP_ADC, OP_SUB, OP_SBB, OP_AND, OP_OR, OP_XOR, OP_CMP, OP_TEST, OP_NEG,
OP_READ_MODRM, /* mod r/mの値を見て演算の種類を決める */
OP_READ_MODRM_MUL, /* mod r/mの値を見て演算の種類を決める(MUL系) */
OP_READ_MODRM_INC /* mod r/mの値を見て演算の種類を決める(INC系) */
} op_arithmetic_kind = OP_ADD; /* 演算命令の種類 */
enum {
OP_ROL, OP_ROR, OP_RCL, OP_RCR, OP_SHL, OP_SHR, OP_SAR,
OP_SHLD, OP_SHRD,
OP_READ_MODRM_SHIFT /* mod r/mの値を見て演算の種類を決める(シフト系) */
} op_shift_kind = OP_ROL;
enum {
OP_STR_MOV,
OP_STR_CMP,
OP_STR_STO,
OP_STR_LOD,
OP_STR_SCA,
OP_STR_IN,
OP_STR_OUT
} op_string_kind = OP_STR_MOV; /* ストリング命令の種類 */
int op_width = 1; /* オペランドのバイト数 */
int jmp_take = 0; /* ジャンプを行うか */
int use_mod_rm = 0; /* mod r/mを使うか */
int is_dest_reg = 0; /* mod r/mを使うとき、結果の書き込み先がr/mではなくregか */
int modrm_disable_src = 0; /* mod r/mを使う時、srcをmod r/mから設定するのをやめるか */
int direct_disp_size = 0; /* moffsを使うとき、そのサイズ */
int is_dest_direct_disp = 0; /* moffsをdestに使うか(sizeが0でないとき、偽 = srcに使う) */
int use_imm = 0; /* 即値を使うか */
int one_byte_imm = 0; /* 即値が1バイトか(偽 = オペランドのサイズ) */
int op_fpu_kind = 0; /* FPU系命令のカテゴリ */
int imul_store_upper = 0; /* IMUL命令において、上位の値を保存するか */
int imul_enable_dest = 0; /* IMUL命令において、destの指定を有効にするか(偽 = AL/AX/EAX固定) */
/* オペランドの情報 */
enum {
OP_KIND_IMM, /* 即値 (imm_value) */
OP_KIND_MEM, /* メモリ上のデータ (*_addr) */
OP_KIND_REG, /* AH/CH/DH/BHではないレジスタ上のデータ (*_reg_index) */
OP_KIND_REG_HIGH8 /* レジスタAH/CH/DH/BH上のデータ (*_reg_index) */
};
uint32_t src_addr = 0;
int src_kind = OP_KIND_IMM;
int src_reg_index = 0;
uint32_t dest_addr = 0;
int dest_kind = OP_KIND_IMM;
int dest_reg_index = 0;
int need_dest_value = 0;
int data_segment = DS;
uint32_t imm_value = 0; /* 即値の値 */
if (use_pe_import && import_params.iat_size >= 4 &&
import_params.iat_addr <= eip && eip - import_params.iat_addr < import_params.iat_size) {
int ret = pe_import(&eip, regs);
if (ret == 0) return 0;
if (ret < 0) {
print_regs(stderr);
return 0;
}
return 1;
}
/* プリフィックスを解析する */
for(;;) {
/* 命令フェッチ */
fetch_data = step_memread(&memread_ok, inst_addr, CS, eip, 1);
if (!memread_ok) return 0;
eip++;
/* プリフィックスか判定 */
if (fetch_data == 0x26) { /* ES override */
data_segment = ES;
} else if (fetch_data == 0x2E) { /* CS override */
data_segment = CS;
} else if (fetch_data == 0x36) { /* SS override */
data_segment = SS;
} else if (fetch_data == 0x3E) { /* DS override */
data_segment = DS;
} else if (fetch_data == 0x64) { /* FS override */
data_segment = FS;
} else if (fetch_data == 0x65) { /* GS override */
data_segment = GS;
} else if (fetch_data == 0x9B) { /* wait */
/* 無視 */
} else if (fetch_data == 0xF0) { /* lock */
/* 無視 */
} else if (fetch_data == 0x66) { /* operand-size override */
is_data_16bit = 1;
} else if (fetch_data == 0x67) { /* address-size override */
is_addr_16bit = 1;
} else if (fetch_data == 0xF2) { /* repnz */
is_rep = 1;
is_rep_while_zero = 0;
} else if (fetch_data == 0xF3) { /* repz */
is_rep = 1;
is_rep_while_zero = 1;
} else {
break;
}
}
#define SET_JMP_TAKE \
switch (fetch_data & 0x0E) { \
case 0x0: jmp_take = (eflags & OF); break; /* JO */ \
case 0x2: jmp_take = (eflags & CF); break; /* JB */ \
case 0x4: jmp_take = (eflags & ZF); break; /* JZ */ \
case 0x6: jmp_take = (eflags & CF) || (eflags & ZF); break; /* JBE */ \
case 0x8: jmp_take = (eflags & SF); break; /* JS */ \
case 0xA: jmp_take = (eflags & PF); break; /* JP */ \
case 0xC: jmp_take = ((eflags & SF) != 0) != ((eflags & OF) != 0); break; /* JL */ \
case 0xE: jmp_take = (eflags & ZF) || (((eflags & SF) != 0) != ((eflags & OF) != 0)); break; /* JLE */ \
} \
if (fetch_data & 0x01) jmp_take = !jmp_take;
/* オペコードを解析する */
if (fetch_data == 0x0F) {
fetch_data = step_memread(&memread_ok, inst_addr, CS, eip, 1);
if (!memread_ok) return 0;
eip++;
if ((fetch_data & 0xF0) == 0x40) {
/* CMOVcc */
if (strict_mode) {
fprintf(stderr, "CMOVcc instruction, not in 80386, detected at %08"PRIx32"\n", inst_addr);
print_regs(stderr);
return 0;
}
op_kind = OP_CMOV;
op_width = is_data_16bit ? 2 : 4;
use_mod_rm = 1;
is_dest_reg = 1;
SET_JMP_TAKE
} else if ((fetch_data & 0xF0) == 0x80) {
/* Jcc rel16/32 */
op_kind = OP_JUMP;
op_width = is_data_16bit ? 2 : 4;
use_imm = 1;
SET_JMP_TAKE
} else if ((fetch_data & 0xF0) == 0x90) {
/* SETcc */
op_kind = OP_SETCC;
op_width = 1;
use_mod_rm = 1;
is_dest_reg = 0;
SET_JMP_TAKE
} else if ((fetch_data & 0xFE) == 0xA4 || (fetch_data & 0xFE) == 0xAC) {
/* SHLD/SHRD */
op_kind = OP_SHIFT;
op_shift_kind = (fetch_data & 8) ? OP_SHRD : OP_SHLD;
op_width = (is_data_16bit ? 2 : 4);
use_mod_rm = 1;
is_dest_reg = 0;
if ((fetch_data & 1) == 0) {
use_imm = 1;
one_byte_imm = 1;
}
need_dest_value = 1;
} else if (fetch_data == 0xAF) {
/* IMUL r16/32, r/m16/32 */
op_kind = OP_IMUL;
op_width = (is_data_16bit ? 2 : 4);
use_mod_rm = 1;
is_dest_reg = 1;
imul_enable_dest = 1;
need_dest_value = 1;
} else if ((fetch_data & 0xFE) == 0xB0) {
/* CMPXCHG */
if (strict_mode) {
fprintf(stderr, "CMPXCHG instruction, not in 80386, detected at %08"PRIx32"\n", inst_addr);
print_regs(stderr);
return 0;
}
op_kind = OP_CMPXCHG;
op_width = (fetch_data & 0x01) ? (is_data_16bit ? 2 : 4) : 1;
use_mod_rm = 1;
is_dest_reg = 0;
need_dest_value = 1;
} else if ((fetch_data & 0xFE) == 0xB6) {
/* MOVZX */
op_kind = OP_MOVZX;
op_width = (fetch_data & 0x01) ? 2 : 1;
use_mod_rm = 1;
is_dest_reg = 1;
} else if ((fetch_data & 0xFE) == 0xBE) {
/* MOVSX */
op_kind = OP_MOVSX;
op_width = (fetch_data & 0x01) ? 2 : 1;
use_mod_rm = 1;
is_dest_reg = 1;
} else {
fprintf(stderr, "unsupported opcode \"0f %02"PRIx8"\" at %08"PRIx32"\n\n", fetch_data, inst_addr);
print_regs(stderr);
return 0;
}
} else {
if (fetch_data <= 0x3F && (fetch_data & 0x07) <= 0x05) {
/* パターンに沿った演算命令 */
op_kind = OP_ARITHMETIC;
/* オペランドを解析 */
switch (fetch_data & 0x07) {
case 0x00: /* r/m8, r8 */
op_width = 1;
use_mod_rm = 1;
is_dest_reg = 0;
break;
case 0x01: /* r/m16/32, r16/32 */
op_width = (is_data_16bit ? 2 : 4);
use_mod_rm = 1;
is_dest_reg = 0;
break;
case 0x02: /* r8, r/m8 */
op_width = 1;
use_mod_rm = 1;
is_dest_reg = 1;
break;
case 0x03: /* r16/32, r/m16/32 */
op_width = (is_data_16bit ? 2 : 4);
use_mod_rm = 1;
is_dest_reg = 1;
break;
case 0x04: /* AL, imm8 */
op_width = 1;
use_mod_rm = 0;
use_imm = 1;
src_kind = OP_KIND_IMM;
dest_kind = OP_KIND_REG;
dest_reg_index = EAX;
break;
case 0x05: /* eAX, imm16/32 */
op_width = (is_data_16bit ? 2 : 4);
use_mod_rm = 0;
use_imm = 1;
src_kind = OP_KIND_IMM;
dest_kind = OP_KIND_REG;
dest_reg_index = EAX;
break;
}
/* 演算の種類を解析 */
switch(fetch_data >> 3) {
case 0: op_arithmetic_kind = OP_ADD; break;
case 1: op_arithmetic_kind = OP_OR; break;
case 2: op_arithmetic_kind = OP_ADC; break;
case 3: op_arithmetic_kind = OP_SBB; break;
case 4: op_arithmetic_kind = OP_AND; break;
case 5: op_arithmetic_kind = OP_SUB; break;
case 6: op_arithmetic_kind = OP_XOR; break;
case 7: op_arithmetic_kind = OP_CMP; break;
}
need_dest_value = 1;
} else if (0x40 <= fetch_data && fetch_data < 0x50) {
/* INC/DEC */
op_kind = OP_INCDEC;
op_width = (is_data_16bit ? 2 : 4);
use_mod_rm = 0;
src_kind = OP_KIND_IMM;
dest_kind = OP_KIND_REG;
dest_reg_index = fetch_data & 0x07;
imm_value = (fetch_data < 0x48 ? 1 : -1);
need_dest_value = 1;
} else if (0x50 <= fetch_data && fetch_data < 0x60) {
/* PUSH/POP */
op_width = (is_data_16bit ? 2 : 4);
use_mod_rm = 0;
if (fetch_data < 0x58) {
op_kind = OP_PUSH;
src_kind = OP_KIND_REG;
src_reg_index = fetch_data & 0x07;
} else {
op_kind = OP_POP;
dest_kind = OP_KIND_REG;
dest_reg_index = fetch_data & 0x07;
}
} else if (fetch_data == 0x60) {
/* PUSHA */
op_kind = OP_PUSHA;
} else if (fetch_data == 0x61) {
/* POPA */
op_kind = OP_POPA;
} else if (fetch_data == 0x68) {
/* PUSH imm16/32 */
op_kind = OP_PUSH;
op_width = (is_data_16bit ? 2 : 4);
use_imm = 1;
src_kind = OP_KIND_IMM;
} else if (fetch_data == 0x69) {
/* IMUL r16/32, r/m16/32, imm16/32 */
op_kind = OP_IMUL;
op_width = (is_data_16bit ? 2 : 4);
use_mod_rm = 1;
is_dest_reg = 1;
use_imm = 1;
imul_enable_dest = 1;
} else if (fetch_data == 0x6A) {
/* PUSH imm8 */
op_kind = OP_PUSH;
op_width = (is_data_16bit ? 2 : 4);
use_imm = 1;
one_byte_imm = 1;
src_kind = OP_KIND_IMM;
} else if (fetch_data == 0x6B) {
/* IMUL r16/32, r/m16/32, imm8 */
op_kind = OP_IMUL;
op_width = (is_data_16bit ? 2 : 4);
use_mod_rm = 1;
is_dest_reg = 1;
use_imm = 1;
one_byte_imm = 1;
imul_enable_dest = 1;
} else if ((fetch_data & 0xFC) == 0x6C) {
/* INS/OUTS */
op_kind = OP_STRING;
op_string_kind = (fetch_data & 0x03) < 2 ? OP_STR_IN : OP_STR_OUT;
op_width = (fetch_data & 0x01) ? (is_data_16bit ? 2 : 4) : 1;
} else if ((0x70 <= fetch_data && fetch_data < 0x80) || fetch_data == 0xE3 || fetch_data == 0xEB) {
/* 分岐 */
op_kind = OP_JUMP;
if (fetch_data == 0xE3) {
/* JCXZ */
jmp_take = ((is_data_16bit ? regs[ECX] & 0xffff : regs[ECX]) == 0);
} else if (fetch_data == 0xEB) {
/* JMP */
jmp_take = 1;
} else {
SET_JMP_TAKE
}
op_width = 1;
use_imm = 1;
} else if (0x80 <= fetch_data && fetch_data <= 0x83) {
/* 定数との演算 */
op_kind = OP_ARITHMETIC;
op_arithmetic_kind = OP_READ_MODRM;
op_width = (fetch_data & 1 ? (is_data_16bit ? 2 : 4) : 1);
use_mod_rm = 1;
modrm_disable_src = 1;
is_dest_reg = 0;
use_imm = 1;
src_kind = OP_KIND_IMM;
if (fetch_data == 0x83) one_byte_imm = 1;
need_dest_value = 1;
} else if (0x84 <= fetch_data && fetch_data <= 0x8B) {
/* 演算 */
if ((fetch_data & 0xFE) == 0x84) {
op_kind = OP_ARITHMETIC;
op_arithmetic_kind = OP_TEST;
need_dest_value = 1;
} else if ((fetch_data & 0xFE) == 0x86) {
op_kind = OP_XCHG;
need_dest_value = 1;
} else {
op_kind = OP_MOV;
}
op_width = (fetch_data & 1 ? (is_data_16bit ? 2 : 4) : 1);
use_mod_rm = 1;
is_dest_reg = (fetch_data & 2);
} else if (fetch_data == 0x8D) {
/* LEA */
op_kind = OP_LEA;
op_width = 4;
use_mod_rm = 1;
is_dest_reg = 1;
} else if (fetch_data == 0x8F) {
/* POP r/m16/32 */
op_kind = OP_POP;
op_width = (is_data_16bit ? 2 : 4);
use_mod_rm = 1;
modrm_disable_src = 1;
is_dest_reg = 0;
} else if (0x90 <= fetch_data && fetch_data < 0x98) {
/* XCHG r16/32, eAX */
op_kind = OP_XCHG;
op_width = (is_data_16bit ? 2 : 4);
src_kind = OP_KIND_REG;
src_reg_index = (fetch_data & 0x07);
dest_kind = OP_KIND_REG;
dest_reg_index = EAX;
need_dest_value = 1;
} else if (fetch_data == 0x98) {
/* CBW/CWDE */
op_kind = OP_CBW;
op_width = (is_data_16bit ? 2 : 4);
src_kind = OP_KIND_REG;
src_reg_index = EAX;
dest_kind = OP_KIND_REG;
dest_reg_index = EAX;
} else if (fetch_data == 0x99) {
/* CWD/CDQ */
op_kind = OP_CWD;
op_width = (is_data_16bit ? 2 : 4);
src_kind = OP_KIND_REG;
src_reg_index = EAX;
dest_kind = OP_KIND_REG;
dest_reg_index = EDX;
} else if (fetch_data == 0x9C) {
/* PUSHF */
op_kind = OP_PUSHF;
op_width = (is_data_16bit ? 2 : 4);
} else if (fetch_data == 0x9D) {
/* POPF */
op_kind = OP_POPF;
op_width = (is_data_16bit ? 2 : 4);
} else if (fetch_data == 0x9E) {
/* SAHF */
op_kind = OP_SAHF;
op_width = 1;
src_kind = OP_KIND_REG;
src_reg_index = EAX;
} else if (fetch_data == 0x9F) {
/* LAHF */
op_kind = OP_LAHF;
op_width = 1;
dest_kind = OP_KIND_REG;
dest_reg_index = EAX;
} else if ((fetch_data & 0xFC) == 0xA0) {
/* MOV with moffs */
op_kind = OP_MOV;
op_width = (fetch_data & 0x01) ? (is_data_16bit ? 2 : 4) : 1;
direct_disp_size = (is_addr_16bit ? 2 : 4);
if ((fetch_data & 0x2) == 0) {
is_dest_direct_disp = 0;
dest_kind = OP_KIND_REG;
dest_reg_index = EAX;
} else {
is_dest_direct_disp = 1;
src_kind = OP_KIND_REG;
src_reg_index = EAX;
}
} else if (0xA4 <= fetch_data && fetch_data <= 0xAF && (fetch_data & 0xFE) != 0xA8) {
/* ストリング命令 */
op_kind = OP_STRING;
switch (fetch_data & 0xFE) {
case 0xA4: op_string_kind = OP_STR_MOV; break;
case 0xA6: op_string_kind = OP_STR_CMP; break;
case 0xAA: op_string_kind = OP_STR_STO; break;
case 0xAC: op_string_kind = OP_STR_LOD; break;
case 0xAE: op_string_kind = OP_STR_SCA; break;
}
op_width = (fetch_data & 1 ? (is_data_16bit ? 2 : 4) : 1);
if (op_string_kind == OP_STR_STO || op_string_kind == OP_STR_SCA) {
src_kind = OP_KIND_REG;
src_reg_index = EAX;
} else if (op_string_kind == OP_STR_LOD) {
dest_kind = OP_KIND_REG;
dest_reg_index = EAX;
}
} else if (fetch_data == 0xA8 || fetch_data == 0xA9) {
/* TEST AL/AX/EAX, imm8/imm16/imm32 */
op_kind = OP_ARITHMETIC;
op_arithmetic_kind = OP_TEST;
op_width = (fetch_data & 1 ? (is_data_16bit ? 2 : 4) : 1);
use_imm = 1;
src_kind = OP_KIND_IMM;
dest_kind = OP_KIND_REG;
dest_reg_index = EAX;
need_dest_value = 1;
} else if (0xB0 <= fetch_data && fetch_data <= 0xBF) {
/* MOV r, imm */
op_kind = OP_MOV;
op_width = (fetch_data & 0x08 ? (is_data_16bit ? 2 : 4) : 1);
use_imm = 1;
src_kind = OP_KIND_IMM;
dest_kind = OP_KIND_REG;
dest_reg_index = fetch_data & 0x07;
} else if (fetch_data == 0xC0 || fetch_data == 0xC1 || (0xD0 <= fetch_data && fetch_data <= 0xD3)) {
/* シフト */
op_kind = OP_SHIFT;
op_shift_kind = OP_READ_MODRM_SHIFT;
op_width = (fetch_data & 1 ? (is_data_16bit ? 2 : 4) : 1);
use_mod_rm = 1;
modrm_disable_src = 1;
is_dest_reg = 0;
switch (fetch_data & 0xFE) {
case 0xC0:
use_imm = 1;
src_kind = OP_KIND_IMM;
one_byte_imm = 1;
break;
case 0xD0:
src_kind = OP_KIND_IMM;
imm_value = 1;
break;
case 0xD2:
src_kind = OP_KIND_REG;
src_reg_index = ECX;
break;
}
need_dest_value = 1;
} else if (fetch_data == 0xC2 || fetch_data == 0xC3) {
/* RETN */
op_kind = OP_RETN;
op_width = 2;
if (fetch_data == 0xC2) {
use_imm = 1;
} else {
imm_value = 0;
}
} else if (fetch_data == 0xC6 || fetch_data == 0xC7) {
/* MOV r, imm */
op_kind = OP_MOV;
op_width = (fetch_data & 1 ? (is_data_16bit ? 2 : 4) : 1);
use_mod_rm = 1;
modrm_disable_src = 1;
is_dest_reg = 0;
use_imm = 1;
src_kind = OP_KIND_IMM;
need_dest_value = 1;
} else if (fetch_data == 0xC9) {
/* LEAVE */
op_kind = OP_LEAVE;
op_width = is_data_16bit ? 2 : 4;
} else if (fetch_data == 0xCC || fetch_data == 0xCD) {
/* INT */
op_kind = OP_INT;
op_width = 1;
if (fetch_data == 0xCC) {
imm_value = 3;
} else {
use_imm = 1;
}
} else if (fetch_data == 0xCE) {
/* INTO */
op_kind = OP_INTO;
} else if (fetch_data == 0xCF) {
/* IRET */
op_kind = OP_IRET;
} else if ((fetch_data & 0xF8) == 0xD8) {
/* FPU instructions */
op_kind = OP_FPU;
use_mod_rm = 1;
op_fpu_kind = fetch_data & 0x07;
} else if (fetch_data == 0xE0 || fetch_data == 0xE1 || fetch_data == 0xE2) {
/* LOOP* */
op_kind = OP_LOOP;
use_imm = 1;
one_byte_imm = 1;
op_width = is_data_16bit ? 2 : 4;
src_kind = OP_KIND_REG;
src_reg_index = ECX;
dest_kind = OP_KIND_REG;
dest_reg_index = ECX;
switch (fetch_data) {
case 0xE0: jmp_take = !(eflags & ZF); break;
case 0xE1: jmp_take = (eflags & ZF); break;
case 0xE2: jmp_take = 1; break;
}
} else if ((fetch_data & 0xFC) == 0xE4 || (fetch_data & 0xFC) == 0xEC) {
/* IN/OUT */
op_width = (fetch_data & 0x01) ? (is_data_16bit ? 2 : 4) : 1;
if (fetch_data <= 0xE7) {
use_imm = 1;
one_byte_imm = 1;
}
if ((fetch_data & 0x03) < 2) {
op_kind = OP_IN;
src_kind = OP_KIND_REG;
src_reg_index = EAX;
if (fetch_data <= 0xE7) {
dest_kind = OP_KIND_IMM;
} else {
dest_kind = OP_KIND_REG;
dest_reg_index = EDX;
need_dest_value = 1;
}
} else {
op_kind = OP_OUT;
dest_kind = OP_KIND_REG;
dest_reg_index = EAX;
if (fetch_data <= 0xE7) {
src_kind = OP_KIND_IMM;
} else {
src_kind = OP_KIND_REG;
src_reg_index = EDX;
}
}
} else if (fetch_data == 0xE8) {
/* CALL */
op_kind = OP_CALL;
op_width = is_data_16bit ? 2 : 4;
use_imm = 1;
} else if (fetch_data == 0xE9) {
/* JUMP */
op_kind = OP_JUMP;
op_width = is_data_16bit ? 2 : 4;
use_imm = 1;
jmp_take = 1;
} else if (fetch_data == 0xF4) {
/* HLT */
op_kind = OP_HLT;
} else if (fetch_data == 0xF5) {
/* CMC */
op_kind = OP_CMC;
} else if (0xF8 <= fetch_data && fetch_data <= 0xFD) {
/* CLC/STC/CLI/STI/CLD/STD */
op_kind = (fetch_data & 0x01) ? OP_SET_FLAG : OP_CLEAR_FLAG;
switch (fetch_data & 0xFE) {
case 0xF8: imm_value = CF; break;
case 0xFA: imm_value = IF; break;
case 0xFC: imm_value = DF; break;
}
} else if ((fetch_data & 0xFE) == 0xF6) {
/* TEST/NOT/NEG/MUL/IMUL/DIV/IDIV */
op_kind = OP_ARITHMETIC;
op_arithmetic_kind = OP_READ_MODRM_MUL;
op_width = (fetch_data & 0x01) ? (is_data_16bit ? 2 : 4) : 1;
use_mod_rm = 1;
} else if ((fetch_data & 0xFE) == 0xFE) {
/* INC/DEC/CALL/CALLF/JMP/JMPF/PUSH */
op_arithmetic_kind = OP_READ_MODRM_INC;
op_width = (fetch_data & 0x01) ? (is_data_16bit ? 2 : 4) : 1;
use_mod_rm = 1;
} else {
fprintf(stderr, "unsupported opcode %02"PRIx8" at %08"PRIx32"\n\n", fetch_data, inst_addr);
print_regs(stderr);
return 0;
}
}
/* mod r/mを解析する */
int use_sib = 0; /* sibを使うか */
int disp_size = 0; /* dispのバイト数 */
int reg_index = 0; /* mod r/m中のregから取得したレジスタ番号 */
int reg_is_high = 0; /* mod r/m中のregがAH/CH/DH/BHか */
int modrm_reg_index = 0; /* mod r/m中のmod r/mで使うレジスタ番号 */
int modrm_reg_is_high = 0; /* mod r/m中のmod r/mで使うレジスタがAH/CH/DH/BHか */
int modrm_reg2_index = 0; /* mod r/m中のmod r/mで使う2個目のレジスタ番号 */
int modrm_reg2_scale = 0; /* mod r/m中のmod r/mで使う2個目のレジスタの係数 */
int modrm_no_reg = 0; /* mod r/m中のmod r/mの実効アドレスで最初のレジスタを使わないか */
int modrm_is_mem = 0; /* mod r/m中のmod r/mがメモリか */
if (use_mod_rm) {
uint8_t mod_rm = step_memread(&memread_ok, inst_addr, CS, eip, 1);
if (!memread_ok) return 0;
eip++;
int mod = (mod_rm >> 6) & 3;
int reg = (mod_rm >> 3) & 7;
int rm = mod_rm & 7;
if (op_arithmetic_kind == OP_READ_MODRM) {
/* 「mod r/mを見て決定する」演算を決定する */
static const int kind_table[] = {
OP_ADD, OP_OR, OP_ADC, OP_SBB, OP_AND, OP_SUB, OP_XOR, OP_CMP
};
op_arithmetic_kind = kind_table[reg];
} else if (op_arithmetic_kind == OP_READ_MODRM_MUL) {
/* 「mod r/mを見て決定する」MUL系の演算を決定する */
static const int op_table[] = {
OP_ARITHMETIC, OP_ARITHMETIC, OP_NOT, OP_ARITHMETIC,
OP_MUL, OP_IMUL, OP_DIV, OP_IDIV
};
op_kind = op_table[reg];
if (reg <= 1) {
op_arithmetic_kind = OP_TEST;
} else if (reg == 3) {
op_arithmetic_kind = OP_NEG;
}
if (reg <= 1) {
use_imm = 1;
src_kind = OP_KIND_IMM;
}
if (reg <= 3) need_dest_value = 1;
if (4 <= reg) is_dest_reg = 1;
if (reg == 4 || reg == 5) imul_store_upper = 1;
} else if (op_arithmetic_kind == OP_READ_MODRM_INC) {
/* 「mod r/mを見て決定する」INC系の演算を決定する */
static const int op_table[] = {
OP_INCDEC, OP_INCDEC,
OP_CALL_ABSOLUTE, OP_CALL_FAR,
OP_JUMP_ABSOLUTE, OP_JUMP_FAR,
OP_PUSH, 0
};
op_kind = op_table[reg];
if (reg <= 1) {
imm_value = (reg == 0 ? 1 : -1);
need_dest_value = 1;
} else if (reg <= 6) {
if (op_width == 1) {
fprintf(stderr, "undefined operation reg=%d at %08"PRIx32"\n", reg, inst_addr);
print_regs(stderr);
return 0;
}
is_dest_reg = 1;
} else {
fprintf(stderr, "undefined operation reg=%d at %08"PRIx32"\n", reg, inst_addr);
print_regs(stderr);
return 0;
}
}
if (op_shift_kind == OP_READ_MODRM_SHIFT) {
/* 「mod r/mを見て決定する」シフト系の演算を決定する */
static const int kind_table[] = {
OP_ROL, OP_ROR, OP_RCL, OP_RCR, OP_SHL, OP_SHR, OP_SHL, OP_SAR
};
op_shift_kind = kind_table[reg];
}
if (op_kind == OP_FPU) {
/* FPU系の演算を決定する */
if (op_fpu_kind == 3 && reg == 4) {
/* FNINIT/FINIT */
/* 無視 */
} else {
fprintf(stderr, "FPU operations are unimplemented at %08"PRIx32"\n", inst_addr);
print_regs(stderr);
return 0;
}
}
if (op_width == 1 && (op_kind != OP_MOVZX && op_kind != OP_MOVSX)) {
if (reg < 4) {
reg_index = reg;
reg_is_high = 0;
} else {
reg_index = reg & 3;
reg_is_high = 1;
}
} else {
reg_index = reg;
reg_is_high = 0;
}
if (mod == 3) {
/* レジスタオペランド */
if (op_width == 1) {
if (rm < 4) {
modrm_reg_index = rm;
modrm_reg_is_high = 0;
} else {
modrm_reg_index = rm & 3;
modrm_reg_is_high = 1;
}
} else {
modrm_reg_index = rm;
modrm_reg_is_high = 0;
}
} else {
/* メモリオペランド */
modrm_is_mem = 1;
if (is_addr_16bit) {
/* 16-bit mod r/m */
if (mod == 0 && rm == 5) {
modrm_no_reg = 1;
disp_size = 2;
} else {
switch (rm) {
case 0: case 1: case 7: modrm_reg_index = EBX; break;
case 2: case 3: case 6: modrm_reg_index = EBP; break;
case 4: modrm_reg_index = ESI; break;
case 5: modrm_reg_index = EDI; break;
}
if (rm == 0 || rm == 2) {
modrm_reg2_index = ESI;
modrm_reg2_scale = 1;
} else if (rm == 1 || rm == 3) {
modrm_reg2_index = EDI;
modrm_reg2_scale = 1;
}
switch (mod) {
case 0: disp_size = 0; break;
case 1: disp_size = 1; break;
case 2: disp_size = 2; break;
}
}
} else {
/* 32-bit mod r/m */
if (mod == 0 && rm == 5) {
modrm_no_reg = 1;
disp_size = 4;
} else {
if (rm == 4) {
use_sib = 1;
} else {
modrm_reg_index = rm;
}
switch (mod) {
case 0: disp_size = 0; break;
case 1: disp_size = 1; break;
case 2: disp_size = 4; break;
}
}
}
}
}
/* SIBを解析する */
if (use_sib) {
uint8_t sib = step_memread(&memread_ok, inst_addr, CS, eip, 1);
if (!memread_ok) return 0;
eip++;
int ss = (sib >> 6) & 3;
int idx = (sib >> 3) & 7;
int r32 = sib & 7;
modrm_reg_index = r32;
if (idx != 4) {
modrm_reg2_index = idx;
switch (ss) {
case 0: modrm_reg2_scale = 1; break;
case 1: modrm_reg2_scale = 2; break;
case 2: modrm_reg2_scale = 4; break;
case 3: modrm_reg2_scale = 8; break;
}
}
if (r32 == 5 && disp_size == 0) {
disp_size = 4;
modrm_no_reg = 1;
}
}
/* dispを解析する */
uint32_t disp = 0;
if (!use_mod_rm) disp_size = direct_disp_size;
if (disp_size > 0) {
disp = step_memread(&memread_ok, inst_addr, CS, eip, disp_size);
if (!memread_ok) return 0;
eip += disp_size;
}