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

Same some space by introducing shorthand byte codes for SSE prefixes

Browse source 
Properly done, all SSE instructions which has the 66/F2/F3 opcode
multiplex need two prefixes: one to control the use of OSP and one to
control the use of REP.  However, it's a four-way select: np/66/F2/F3;
so introduce shorthand bytecodes for that purpose.
This commit is contained in:
H. Peter Anvin 2008-05-20 09:46:24 -07:00
parent 24860b0f0e
commit fff5a47e65
3 changed files with 53 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

27
assemble.c
View file

@ -91,6 +91,10 @@
* \335 - disassemble a rep (0xF3 byte) prefix as repe not rep.
* \340 - reserve <operand 0> bytes of uninitialized storage.
* Operand 0 had better be a segmentless constant.
* \360 - no SSE prefix (== \364\331)
* \361 - 66 SSE prefix (== \366\331)
* \362 - F2 SSE prefix (== \364\332)
* \363 - F3 SSE prefix (== \364\333)
* \364 - operand-size prefix (0x66) not permitted
* \365 - address-size prefix (0x67) not permitted
* \366 - operand-size prefix (0x66) used as opcode extension
@ -1077,6 +1081,13 @@ static int64_t calcsize(int32_t segment, int64_t offset, int bits,
else
length += ins->oprs[0].offset;
break;
case 0360:
break;
case 0361:
case 0362:
case 0363:
length++;
break;
case 0364:
case 0365:
break;
@ -1732,6 +1743,22 @@ static void gencode(int32_t segment, int64_t offset, int bits,
}
break;
case 0360:
break;
case 0361:
bytes[0] = 0x66;
out(offset, segment, bytes, OUT_RAWDATA, 1, NO_SEG, NO_SEG);
offset += 1;
break;
case 0362:
case 0363:
bytes[0] = c - 0362 + 0xf2;
out(offset, segment, bytes, OUT_RAWDATA, 1, NO_SEG, NO_SEG);
offset += 1;
break;
case 0364:
case 0365:
break;

20
disasm.c
View file

@ -874,6 +874,26 @@ static int matches(const struct itemplate *t, uint8_t *data,
case 0340:
return false;
case 0360:
if (prefix->osp || prefix->rep)
return false;
break;
case 0361:
if (!prefix->osp || prefix->rep)
return false;
break;
case 0362:
if (prefix->osp || prefix->rep != 0xf2)
return false;
break;
case 0363:
if (prefix->osp || prefix->rep != 0xf3)
return false;
break;
case 0364:
if (prefix->osp)
return false;

10
insns.pl
View file

@ -539,13 +539,13 @@ sub byte_code_compile($) {
} elsif ($prefix_ok && $op =~ /^(66|f2|f3|np)$/) {
# 66/F2/F3 prefix used as an opcode extension, or np = no prefix
if ($op eq '66') {
push(@codes, 0366, 0331);
push(@codes, 0361);
} elsif ($op eq 'f2') {
push(@codes, 0332, 0364);
push(@codes, 0362);
} elsif ($op eq 'f3') {
push(@codes, 0333, 0364);
push(@codes, 0363);
} else {
push(@codes, 0331, 0364);
push(@codes, 0360);
}
} elsif ($op =~ /^[0-9a-f]{2}$/) {
if (defined($litix) && $litix+$codes[$litix]+1 == scalar @codes) {
@ -678,6 +678,7 @@ sub byte_code_compile($) {
die "$0: $line: $op without 'i' and 's' operands\n";
}
push(@codes, 0172, ($oppos{'s'} << 3)+$oppos{'i'});
$prefix_ok = 0;
} elsif ($op =~ /^(is4|imz2)\=([0-9]+)$/) {
my $imm = $2;
if (!defined($oppos{'s'})) {
@ -687,6 +688,7 @@ sub byte_code_compile($) {
die "$0: $line: invalid imm4 value for $op: $imm\n";
}
push(@codes, 0173, ($oppos{'s'} << 4) + $imm);
$prefix_ok = 0;
} elsif ($op =~ /^([0-9a-f]{2})\+s$/) {
if (!defined($oppos{'i'})) {
die "$0: $op without 'i' operand\n";