procyberian/nasm
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Correct /is4 encoding for EVEX instructions

Browse source 
For EVEX instructions, /is4 can contain a fifth register bit, encoded
in bit 3 of the imm8.  Properly generate this case, and simplifiy the
/is4 generation code somewhat.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
H. Peter Anvin 2016-09-20 16:39:46 -07:00
parent ae707bace4
commit 976ba73062
1 changed files with 19 additions and 18 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

37
assemble.c
View file

@ -1435,6 +1435,7 @@ static void gencode(int32_t segment, int64_t offset, int bits,
const uint8_t *codes = temp->code;
uint8_t opex = 0;
enum ea_type eat = EA_SCALAR;
int r;
ins->rex_done = false;
@ -1607,36 +1608,36 @@ static void gencode(int32_t segment, int64_t offset, int bits,
break;
case 0172:
{
int mask = ins->prefixes[PPS_VEX] == P_EVEX ? 7 : 15;
const struct operand *opy;
c = *codes++;
opx = &ins->oprs[c >> 3];
bytes[0] = nasm_regvals[opx->basereg] << 4;
opx = &ins->oprs[c & 7];
if (opx->segment != NO_SEG || opx->wrt != NO_SEG) {
opy = &ins->oprs[c & 7];
if (opy->segment != NO_SEG || opy->wrt != NO_SEG) {
nasm_error(ERR_NONFATAL,
"non-absolute expression not permitted as argument %d",
c & 7);
} else {
if (opx->offset & ~15) {
nasm_error(ERR_WARNING | ERR_PASS2 | ERR_WARN_NOV,
"four-bit argument exceeds bounds");
}
bytes[0] |= opx->offset & 15;
} else if (opy->offset & ~mask) {
nasm_error(ERR_WARNING | ERR_PASS2 | ERR_WARN_NOV,
"is4 argument exceeds bounds");
}
out(offset, segment, bytes, OUT_RAWDATA, 1, NO_SEG, NO_SEG);
offset++;
break;
c = opy->offset & mask;
goto emit_is4;
}
case 0173:
c = *codes++;
opx = &ins->oprs[c >> 4];
bytes[0] = nasm_regvals[opx->basereg] << 4;
bytes[0] |= c & 15;
out(offset, segment, bytes, OUT_RAWDATA, 1, NO_SEG, NO_SEG);
offset++;
break;
c &= 15;
goto emit_is4;
case4(0174):
bytes[0] = nasm_regvals[opx->basereg] << 4;
c = 0;
emit_is4:
r = nasm_regvals[opx->basereg];
bytes[0] = (r << 4) | ((r & 0x10) >> 1) | c;
out(offset, segment, bytes, OUT_RAWDATA, 1, NO_SEG, NO_SEG);
offset++;
break;