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Initial support for generating DREX suffixes

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Initial support for generating DREX suffixes.  Not used yet.  No
disassembler support yet, and no support for "operand X must match
operand Y."
This commit is contained in:
H. Peter Anvin 2007-09-17 16:55:04 -07:00
parent 8f94f988f0
commit 401c07e20d
2 changed files with 66 additions and 3 deletions
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64
assemble.c
View File

@ -39,9 +39,16 @@
* \150..\153 - an immediate dword or signed byte for operand 0..3
* \154..\157 - or 2 (s-field) into next opcode byte if operand 0..3
* is a signed byte rather than a dword.
* \160..\163 - this instruction uses DREX rather than REX, with the
* OC0 field set to 0, and the dest field taken from
* operand 0..3.
* \164..\167 - this instruction uses DREX rather than REX, with the
* OC0 field set to 1, and the dest field taken from
* operand 0..3.
* \170 - encodes the literal byte 0. (Some compilers don't take
* kindly to a zero byte in the _middle_ of a compile time
* string constant, so I had to put this hack in.)
* \171 - placement of DREX suffix in the absence of an EA
* \2ab - a ModRM, calculated on EA in operand a, with the spare
* field equal to digit b.
* \30x - might be an 0x67 byte, depending on the address size of
@ -843,9 +850,25 @@ static int32_t calcsize(int32_t segment, int32_t offset, int bits,
codes += 2;
length++;
break;
case 0160:
case 0161:
case 0162:
case 0163:
length++;
ins->rex |= REX_D;
break;
case 0164:
case 0165:
case 0166:
case 0167:
length++;
ins->rex |= REX_D|REX_OC;
break;
case 0170:
length++;
break;
case 0171:
break;
case 0300:
case 0301:
case 0302:
@ -945,7 +968,14 @@ static int32_t calcsize(int32_t segment, int32_t offset, int bits,
}
ins->rex &= rex_mask;
if (ins->rex & REX_REAL) {
if (ins->rex & REX_D) {
if (ins->rex & REX_H) {
errfunc(ERR_NONFATAL, "cannot use high register in drex instruction");
return -1;
}
length++;
} else if (ins->rex & REX_REAL) {
if (ins->rex & REX_H) {
errfunc(ERR_NONFATAL, "cannot use high register in rex instruction");
return -1;
@ -964,7 +994,7 @@ static int32_t calcsize(int32_t segment, int32_t offset, int bits,
}
#define EMIT_REX() \
if((ins->rex & REX_REAL) && (bits == 64)) { \
if (!(ins->rex & REX_D) && (ins->rex & REX_REAL) && (bits == 64)) { \
ins->rex = (ins->rex & REX_REAL)|REX_P; \
out(offset, segment, &ins->rex, OUT_RAWDATA+1, NO_SEG, NO_SEG); \
ins->rex = 0; \
@ -1320,12 +1350,33 @@ static void gencode(int32_t segment, int32_t offset, int bits,
offset++;
break;
case 0160:
case 0161:
case 0162:
case 0163:
case 0164:
case 0165:
case 0166:
case 0167:
ins->drexdst = regval(&ins->oprs[c & 3]);
break;
case 0170:
bytes[0] = 0;
out(offset, segment, bytes, OUT_RAWDATA + 1, NO_SEG, NO_SEG);
offset += 1;
break;
case 0171:
bytes[0] =
(ins->drexdst << 4) |
(ins->rex & REX_OC ? 0x08 : 0) |
(ins->rex & (REX_R|REX_X|REX_B));
ins->rex = 0;
out(offset, segment, bytes, OUT_RAWDATA + 1, NO_SEG, NO_SEG);
offset++;
break;
case 0300:
case 0301:
case 0302:
@ -1487,6 +1538,15 @@ static void gencode(int32_t segment, int32_t offset, int bits,
if (ea_data.sib_present)
*p++ = ea_data.sib;
/* DREX suffixes come between the SIB and the displacement */
if (ins->rex & REX_D) {
*p++ =
(ins->drexdst << 4) |
(ins->rex & REX_OC ? 0x08 : 0) |
(ins->rex & (REX_R|REX_X|REX_B));
ins->rex = 0;
}
s = p - bytes;
out(offset, segment, bytes, OUT_RAWDATA + s,
NO_SEG, NO_SEG);

5
nasm.h
View File

@ -540,6 +540,8 @@ enum ccode { /* condition code names */
/*
* REX flags
*/
#define REX_OC 0x0200 /* DREX suffix has the OC0 bit set */
#define REX_D 0x0100 /* Instruction uses DREX instead of REX */
#define REX_H 0x80 /* High register present, REX forbidden */
#define REX_P 0x40 /* REX prefix present/required */
#define REX_L 0x20 /* Use LOCK prefix instead of REX.R */
@ -622,7 +624,8 @@ typedef struct { /* an instruction itself */
int eops_float; /* true if DD and floating */
int32_t times; /* repeat count (TIMES prefix) */
int forw_ref; /* is there a forward reference? */
uint8_t rex; /* Special REX Prefix */
int rex; /* Special REX Prefix */
int drexdst; /* Destination register for DREX suffix */
} insn;
enum geninfo { GI_SWITCH };