/*
* decode_prefixes
*
* Extracts instruction prefixes.
*/
static int
decode_prefixes(struct ud *u)
{
int done = 0;
uint8_t curr, last = 0;
UD_RETURN_ON_ERROR(u);
do {
last = curr;
curr = inp_next(u);
UD_RETURN_ON_ERROR(u);
if (u->inp_ctr == MAX_INSN_LENGTH) {
UD_RETURN_WITH_ERROR(u, "max instruction length");
}
switch (curr)
{
case 0x2E:
u->pfx_seg = UD_R_CS;
break;
case 0x36:
u->pfx_seg = UD_R_SS;
break;
case 0x3E:
u->pfx_seg = UD_R_DS;
break;
case 0x26:
u->pfx_seg = UD_R_ES;
break;
case 0x64:
u->pfx_seg = UD_R_FS;
break;
case 0x65:
u->pfx_seg = UD_R_GS;
break;
case 0x67: /* adress-size override prefix */
u->pfx_adr = 0x67;
break;
case 0xF0:
u->pfx_lock = 0xF0;
break;
case 0x66:
u->pfx_opr = 0x66;
break;
case 0xF2:
u->pfx_str = 0xf2;
break;
case 0xF3:
u->pfx_str = 0xf3;
break;
default:
/* consume if rex */
done = (u->dis_mode == 64 && (curr & 0xF0) == 0x40) ? 0 : 1;
break;
}
} while (!done);
/* rex prefixes in 64bit mode, must be the last prefix */
if (u->dis_mode == 64 && (last & 0xF0) == 0x40) {
u->pfx_rex = last;
}
return 0;
}
/*
* decode_prefixes
*
* Extracts instruction prefixes.
*/
static int
decode_prefixes(struct ud *u)
{
int done = 0;
uint8_t curr;
UD_RETURN_ON_ERROR(u);
do {
ud_inp_next(u);
UD_RETURN_ON_ERROR(u);
if (inp_len(u) == MAX_INSN_LENGTH) {
UD_RETURN_WITH_ERROR(u, "max instruction length");
}
curr = inp_curr(u);
switch (curr)
{
case 0x2E :
u->pfx_seg = UD_R_CS;
break;
case 0x36 :
u->pfx_seg = UD_R_SS;
break;
case 0x3E :
u->pfx_seg = UD_R_DS;
break;
case 0x26 :
u->pfx_seg = UD_R_ES;
break;
case 0x64 :
u->pfx_seg = UD_R_FS;
break;
case 0x65 :
u->pfx_seg = UD_R_GS;
break;
case 0x67 : /* adress-size override prefix */
u->pfx_adr = 0x67;
break;
case 0xF0 :
u->pfx_lock = 0xF0;
break;
case 0x66:
u->pfx_opr = 0x66;
break;
case 0xF2:
u->pfx_str = 0xf2;
break;
case 0xF3:
u->pfx_str = 0xf3;
break;
default:
done = 1;
break;
}
} while (!done);
if (u->dis_mode == 64 && (curr & 0xF0) == 0x40) {
/* rex prefixes in 64bit mode, must be the last prefix
*/
u->pfx_rex = curr;
} else {
/* rewind back one byte in stream, since the above loop
* stops with a non-prefix byte.
*/
inp_back(u);
}
return 0;
}
