disasm.cc
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// disasm.cc
// 1/27/2013 jichi
// Original source: http://hack-expo.void.ru/groups/blt/text/disasm.txt
//
// 7/19/2014 jichi: Need to add SSE instruction support for PCSX2
// Sample problematic input from Fate/Stay night PS2:
// 3024b80c -0f88 ae58dbd2 js pcsx2.030010c0
// 3024b812 0f1201 movlps xmm0,qword ptr ds:[ecx] ; jichi: hook here
// 3024b815 0f1302 movlps qword ptr ds:[edx],xmm0
#include "disasm.h"
#include <windows.h>
// disasm_flag values:
enum : unsigned {
C_66 = 0x00000001 // 66-prefix
, C_67 = 0x00000002 // 67-prefix
, C_LOCK = 0x00000004 // lock
, C_REP = 0x00000008 // repz/repnz
, C_SEG = 0x00000010 // seg-prefix
, C_OPCODE2 = 0x00000020 // 2nd opcode present (1st==0f)
, C_MODRM = 0x00000040 // modrm present
, C_SIB = 0x00000080 // sib present
, C_ANYPREFIX = (C_66|C_67|C_LOCK|C_REP|C_SEG)
};
DISASM_BEGIN_NAMESPACE
// These values are served as the output of disasm
// But the are currently unused and could make disasm thread-unsafe
namespace { // unnamed
BYTE disasm_seg // CS DS ES SS FS GS
, disasm_rep // REPZ/REPNZ
, disasm_opcode // opcode
, disasm_opcode2 // used when opcode==0f
, disasm_modrm // modxxxrm
, disasm_sib // scale-index-base
, disasm_mem[8] // mem addr value
, disasm_data[8] // data value
;
} // unnamed namespace
// return: length if success, 0 if error
size_t disasm(const void *opcode0)
{
const BYTE *opcode = (const BYTE *)opcode0;
DWORD disasm_len = 0, // 0 if error
disasm_flag = 0, // C_xxx
disasm_memsize = 0, // value = disasm_mem
disasm_datasize = 0, // value = disasm_data
disasm_defdata = 4, // == C_66 ? 2 : 4
disasm_defmem = 4; // == C_67 ? 2 : 4
retry:
disasm_opcode = *opcode++;
switch (disasm_opcode) {
case 0x99: // 7/20/2014 jichi: CDQ, size = 1
break;
case 0x00: case 0x01: case 0x02: case 0x03:
case 0x08: case 0x09: case 0x0a: case 0x0b:
case 0x10: case 0x11: case 0x12: case 0x13:
case 0x18: case 0x19: case 0x1a: case 0x1b:
case 0x20: case 0x21: case 0x22: case 0x23:
case 0x28: case 0x29: case 0x2a: case 0x2b:
case 0x30: case 0x31: case 0x32: case 0x33:
case 0x38: case 0x39: case 0x3a: case 0x3b:
case 0x62: case 0x63:
case 0x84: case 0x85: case 0x86: case 0x87:
case 0x88: case 0x89: case 0x8a: case 0x8b:
case 0x8c: case 0x8d: case 0x8e: case 0x8f:
case 0xc4: case 0xc5:
case 0xd0: case 0xd1: case 0xd2: case 0xd3:
case 0xd8: case 0xd9: case 0xda: case 0xdb:
case 0xdc: case 0xdd: case 0xde: case 0xdf:
case 0xfe: case 0xff:
disasm_flag |= C_MODRM;
break;
case 0xcd: disasm_datasize += *opcode==0x20 ? 1+4 : 1;
break;
case 0xf6:
case 0xf7: disasm_flag |= C_MODRM;
if (*opcode & 0x38) break;
// continue if <test ..., xx>
case 0x04: case 0x05: case 0x0c: case 0x0d:
case 0x14: case 0x15: case 0x1c: case 0x1d:
case 0x24: case 0x25: case 0x2c: case 0x2d:
case 0x34: case 0x35: case 0x3c: case 0x3d:
if (disasm_opcode & 1)
disasm_datasize += disasm_defdata;
else
disasm_datasize++;
break;
case 0x6a:
case 0xa8:
case 0xb0: case 0xb1: case 0xb2: case 0xb3:
case 0xb4: case 0xb5: case 0xb6: case 0xb7:
case 0xd4: case 0xd5:
case 0xe4: case 0xe5: case 0xe6: case 0xe7:
case 0x70: case 0x71: case 0x72: case 0x73:
case 0x74: case 0x75: case 0x76: case 0x77:
case 0x78: case 0x79: case 0x7a: case 0x7b:
case 0x7c: case 0x7d: case 0x7e: case 0x7f:
case 0xeb:
case 0xe0: case 0xe1: case 0xe2: case 0xe3:
disasm_datasize++;
break;
case 0x26: case 0x2e: case 0x36: case 0x3e:
case 0x64: case 0x65:
if (disasm_flag & C_SEG) return 0;
disasm_flag |= C_SEG;
disasm_seg = disasm_opcode;
goto retry;
case 0xf0:
if (disasm_flag & C_LOCK) return 0;
disasm_flag |= C_LOCK;
goto retry;
case 0xf2: case 0xf3:
if (disasm_flag & C_REP) return 0;
disasm_flag |= C_REP;
disasm_rep = disasm_opcode;
goto retry;
case 0x66:
if (disasm_flag & C_66) return 0;
disasm_flag |= C_66;
disasm_defdata = 2;
goto retry;
case 0x67:
if (disasm_flag & C_67) return 0;
disasm_flag |= C_67;
disasm_defmem = 2;
goto retry;
case 0x6b:
case 0x80:
case 0x82:
case 0x83:
case 0xc0:
case 0xc1:
case 0xc6: disasm_datasize++;
disasm_flag |= C_MODRM;
break;
case 0x69:
case 0x81:
case 0xc7:
disasm_datasize += disasm_defdata;
disasm_flag |= C_MODRM;
break;
case 0x9a:
case 0xea: disasm_datasize += 2 + disasm_defdata;
break;
case 0xa0:
case 0xa1:
case 0xa2:
case 0xa3: disasm_memsize += disasm_defmem;
break;
case 0x68:
case 0xa9:
case 0xb8: case 0xb9: case 0xba: case 0xbb:
case 0xbc: case 0xbd: case 0xbe: case 0xbf:
case 0xe8:
case 0xe9:
disasm_datasize += disasm_defdata;
break;
case 0xc2:
case 0xca: disasm_datasize += 2;
break;
case 0xc8:
disasm_datasize += 3;
break;
case 0xf1:
return 0;
case 0x0f:
// 7/19/2014 jichi: 0x0f1201 = movlps xmm0,qword ptr ds:[ecx]
// Given 0x0f1201, 0x0f will be strip off here and left 0x1201
disasm_flag |= C_OPCODE2;
disasm_opcode2 = *opcode++;
switch (disasm_opcode2) {
case 0x00: case 0x01: case 0x02: case 0x03:
case 0x90: case 0x91: case 0x92: case 0x93:
case 0x94: case 0x95: case 0x96: case 0x97:
case 0x98: case 0x99: case 0x9a: case 0x9b:
case 0x9c: case 0x9d: case 0x9e: case 0x9f:
case 0xa3:
case 0xa5:
case 0xab:
case 0xad:
case 0xaf:
case 0xb0: case 0xb1: case 0xb2: case 0xb3:
case 0xb4: case 0xb5: case 0xb6: case 0xb7:
case 0xbb:
case 0xbc: case 0xbd: case 0xbe: case 0xbf:
case 0xc0:
case 0xc1:
// 7/19/2014 jichi: Add more cases for SSE instructions
// Sample instructions I need to consider
// 0f1201 movlps xmm0,qword ptr ds:[ecx] ; jichi: hook here
// 0f1302 movlps qword ptr ds:[edx],xmm0
case 0x12:
case 0x13:
disasm_flag |= C_MODRM;
break;
case 0x06:
case 0x08: case 0x09: case 0x0a: case 0x0b:
case 0xa0: case 0xa1: case 0xa2: case 0xa8:
case 0xa9:
case 0xaa:
case 0xc8: case 0xc9: case 0xca: case 0xcb:
case 0xcc: case 0xcd: case 0xce: case 0xcf:
break;
case 0x80: case 0x81: case 0x82: case 0x83:
case 0x84: case 0x85: case 0x86: case 0x87:
case 0x88: case 0x89: case 0x8a: case 0x8b:
case 0x8c: case 0x8d: case 0x8e: case 0x8f:
disasm_datasize += disasm_defdata;
break;
case 0xa4:
case 0xac:
case 0xba:
default: return 0; // 7/19/2014 jichi: error
} // 0F-switch
break;
} // switch
if (disasm_flag & C_MODRM) {
disasm_modrm = *opcode++;
BYTE mod = disasm_modrm & 0xc0;
BYTE rm = disasm_modrm & 0x07;
if (mod != 0xc0) {
if (mod == 0x40)
disasm_memsize++;
if (mod == 0x80)
disasm_memsize += disasm_defmem;
if (disasm_defmem == 2) { // modrm16
if (mod == 0x00 && rm == 0x06)
disasm_memsize += 2;
} else { // modrm32
if (rm == 0x04) {
disasm_flag |= C_SIB;
disasm_sib = *opcode++;
rm = disasm_sib & 0x07;
}
if (rm == 0x05 && mod == 0x00)
disasm_memsize += 4;
}
}
} // C_MODRM
for (DWORD i = 0; i < disasm_memsize; i++)
disasm_mem[i] = *opcode++;
for (DWORD i = 0; i < disasm_datasize; i++)
disasm_data[i] = *opcode++;
disasm_len = opcode - (const BYTE *)opcode0;
return disasm_len;
} // disasm
DISASM_END_NAMESPACE
// EOF