/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/log/check.h"
#include "libc/str/str.h"
#include "third_party/zlib/zlib.h"
#include "tool/build/lib/dis.h"
#include "tool/build/lib/high.h"
#include "tool/build/lib/modrm.h"
static const char kJcxz[3][6] = {"jcxz", "jecxz", "jrcxz"};
static const char kAluOp[8][4] = {"add", "or", "adc", "sbb",
"and", "sub", "xor", "cmp"};
static const char kBitOp[8][4] = {"rol", "ror", "rcl", "rcr",
"shl", "shr", "sal", "sar"};
static const char kCc[16][3] = {"o", "no", "b", "ae", "e", "ne", "be", "a",
"s", "ns", "p", "np", "l", "ge", "le", "g"};
static bool IsProbablyByteOp(struct XedDecodedInst *x) {
return !(x->op.opcode & 1);
}
static int IsRepOpcode(struct Dis *d) {
switch (d->xedd->op.opcode & ~1) {
case 0x6C: // INS
return 1;
case 0x6E: // OUTS
return 1;
case 0xA4: // MOVS
return 1;
case 0xAA: // STOS
return 1;
case 0xAC: // LODS
return 1;
case 0xA6: // CMPS
return 2;
case 0xAE: // SCAS
return 2;
default:
return 0;
}
}
static char *DisRepPrefix(struct Dis *d, char *p) {
const char *s;
if (Rep(d->xedd->op.rde) && d->xedd->op.map == XED_ILD_MAP0) {
switch (IsRepOpcode(d)) {
case 0:
break;
case 1:
p = stpcpy(p, "rep ");
break;
case 2:
p = stpcpy(p, Rep(d->xedd->op.rde) == 2 ? "repnz " : "repz ");
break;
default:
break;
}
}
return p;
}
static char *DisBranchTaken(struct Dis *d, char *p) {
switch (d->xedd->op.hint) {
case XED_HINT_NTAKEN:
return stpcpy(p, ",pn");
case XED_HINT_TAKEN:
return stpcpy(p, ",pt");
default:
return p;
}
}
static char *DisName(struct Dis *d, char *bp, const char *name,
bool ambiguous) {
char *p, *np;
uint32_t rde;
bool notbyte, notlong, wantsuffix, wantsuffixsd;
p = bp;
rde = d->xedd->op.rde;
if (d->xedd->op.lock) p = stpcpy(p, "lock ");
p = DisRepPrefix(d, p);
if (strcmp(name, "BIT") == 0) {
p = stpcpy(p, kBitOp[ModrmReg(rde)]);
} else if (strcmp(name, "nop") == 0 && d->xedd->op.rep) {
p = stpcpy(p, "pause");
} else if (strcmp(name, "CALL") == 0) {
p = stpcpy(p, "call");
} else if (strcmp(name, "JMP") == 0) {
p = stpcpy(p, "jmp");
} else if (strcmp(name, "jcxz") == 0) {
p = stpcpy(p, kJcxz[Eamode(rde)]);
p = DisBranchTaken(d, p);
} else if (strcmp(name, "loop") == 0 || strcmp(name, "loope") == 0 ||
strcmp(name, "loopne") == 0) {
p = stpcpy(p, name);
if (Eamode(rde) != Mode(rde)) {
*p++ = "wl"[Eamode(rde)];
*p = '\0';
}
p = DisBranchTaken(d, p);
} else if (strcmp(name, "cwtl") == 0) {
if (Osz(rde)) name = "cbtw";
if (Rexw(rde)) name = "cltq";
p = stpcpy(p, name);
} else if (strcmp(name, "cltd") == 0) {
if (Osz(rde)) name = "cwtd";
if (Rexw(rde)) name = "cqto";
p = stpcpy(p, name);
} else {
notbyte = false;
notlong = false;
wantsuffix = false;
wantsuffixsd = false;
for (np = name; *np && (islower(*np) || isdigit(*np)); ++np) {
*p++ = *np;
}
if (strcmp(name, "ALU") == 0) {
p = stpcpy(p, kAluOp[(d->xedd->op.opcode & 070) >> 3]);
} else if (strcmp(name, "ALU2") == 0) {
p = stpcpy(p, kAluOp[ModrmReg(rde)]);
} else if (strcmp(np, "WLQ") == 0) {
notbyte = true;
wantsuffix = true;
} else if (strcmp(np, "CC") == 0) {
p = stpcpy(p, kCc[d->xedd->op.opcode & 15]);
p = DisBranchTaken(d, p);
} else if (strcmp(np, "WQ") == 0) {
notbyte = true;
notlong = Eamode(rde) != XED_MODE_REAL;
wantsuffix = true;
} else if (strcmp(np, "LQ") == 0 || strcmp(np, "WL") == 0) {
notbyte = true;
wantsuffix = true;
} else if (strcmp(np, "SD") == 0) {
notbyte = true;
wantsuffixsd = true;
} else if (strcmp(np, "ABS") == 0) {
if (Rexw(rde)) p = stpcpy(p, "abs");
}
if (wantsuffixsd) {
if (Osz(rde)) {
*p++ = 'd';
} else {
*p++ = 's';
}
} else if (wantsuffix || (ambiguous && !startswith(name, "f") &&
!startswith(name, "set"))) {
if (Osz(rde)) {
if (ambiguous || Mode(rde) != XED_MODE_REAL) {
*p++ = 'w';
}
} else if (Rexw(rde)) {
*p++ = 'q';
} else if (ambiguous && !notbyte && IsProbablyByteOp(d->xedd)) {
*p++ = 'b';
} else if (!notlong) {
*p++ = 'l';
}
}
}
*p++ = ' ';
while (p - bp < 8) *p++ = ' ';
*p = '\0';
return p;
}
/**
* Disassembles instruction based on string spec.
* @see DisSpec()
*/
char *DisInst(struct Dis *d, char *p, const char *spec) {
long i, n;
char sbuf[64];
char args[4][256];
char *s, *name, *state;
bool hasarg, hasmodrm, hasregister, hasmemory;
CHECK_EQ(0, (int)d->xedd->op.error);
DCHECK_LT(strlen(spec), 128);
hasarg = false;
hasmodrm = d->xedd->op.has_modrm;
hasmemory = hasmodrm && !IsModrmRegister(d->xedd->op.rde);
hasregister = hasmodrm && IsModrmRegister(d->xedd->op.rde);
name = strtok_r(strcpy(sbuf, spec), " ", &state);
for (n = 0; (s = strtok_r(NULL, " ", &state)); ++n) {
hasarg = true;
hasregister |= *s == '%';
hasmemory |= *s == 'O';
CHECK_LT(DisArg(d, args[n], s) - args[n], sizeof(args[n]));
}
p = HighStart(p, g_high.keyword);
p = DisName(d, p, name, hasarg && !hasregister && hasmemory);
p = HighEnd(p);
for (i = 0; i < n; ++i) {
if (i && args[n - i][0]) {
*p++ = ',';
}
p = stpcpy(p, args[n - i - 1]);
}
return p;
}