mirror of
https://github.com/jart/cosmopolitan.git
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f4f4caab0e
I wanted a tiny scriptable meltdown proof way to run userspace programs and visualize how program execution impacts memory. It helps to explain how things like Actually Portable Executable works. It can show you how the GCC generated code is going about manipulating matrices and more. I didn't feel fully comfortable with Qemu and Bochs because I'm not smart enough to understand them. I wanted something like gVisor but with much stronger levels of assurances. I wanted a single binary that'll run, on all major operating systems with an embedded GPL barrier ZIP filesystem that is tiny enough to transpile to JavaScript and run in browsers too. https://justine.storage.googleapis.com/emulator625.mp4
192 lines
7.7 KiB
C
192 lines
7.7 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/calls.h"
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#include "libc/log/check.h"
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#include "libc/macros.h"
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#include "libc/stdio/stdio.h"
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#include "libc/str/str.h"
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#include "libc/sysv/consts/o.h"
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#include "third_party/xed/x86.h"
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const char kPrefixes[][8] = {
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{},
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{0x66},
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{0x67},
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{0x40},
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{0x6F},
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{0x66, 0x6F},
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{0x66, 0x40},
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{0x66, 0x6F},
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{0x67, 0x40},
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{0x67, 0x6F},
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{0x66, 0x67},
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{0x66, 0x67, 0x40},
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{0x66, 0x67, 0x6F},
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{0x0F},
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{0x0F, 0x66},
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{0x0F, 0x67},
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{0x0F, 0x40},
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{0x0F, 0x6F},
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{0x0F, 0x66, 0x6F},
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{0x0F, 0x66, 0x40},
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{0x0F, 0x66, 0x6F},
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{0x0F, 0x67, 0x40},
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{0x0F, 0x67, 0x6F},
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{0x0F, 0x66, 0x67},
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{0x0F, 0x66, 0x67, 0x40},
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{0x0F, 0x66, 0x67, 0x6F},
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{0xF3, 0x0F},
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{0xF3, 0x66, 0x0F},
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{0xF3, 0x67, 0x0F},
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{0xF3, 0x40, 0x0F},
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{0xF3, 0x6F, 0x0F},
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{0xF3, 0x66, 0x6F, 0x0F},
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{0xF3, 0x66, 0x40, 0x0F},
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{0xF3, 0x66, 0x6F, 0x0F},
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{0xF3, 0x67, 0x40, 0x0F},
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{0xF3, 0x67, 0x6F, 0x0F},
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{0xF3, 0x66, 0x67, 0x0F},
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{0xF3, 0x66, 0x67, 0x40, 0x0F},
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{0xF3, 0x66, 0x67, 0x6F, 0x0F},
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{0xF2, 0x0F},
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{0xF2, 0x66, 0x0F},
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{0xF2, 0x67, 0x0F},
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{0xF2, 0x40, 0x0F},
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{0xF2, 0x6F, 0x0F},
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{0xF2, 0x66, 0x6F, 0x0F},
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{0xF2, 0x66, 0x40, 0x0F},
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{0xF2, 0x66, 0x6F, 0x0F},
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{0xF2, 0x67, 0x40, 0x0F},
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{0xF2, 0x67, 0x6F, 0x0F},
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{0xF2, 0x66, 0x67, 0x0F},
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{0xF2, 0x66, 0x67, 0x40, 0x0F},
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{0xF2, 0x66, 0x67, 0x6F, 0x0F},
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};
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const uint8_t kModrmPicks[] = {
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0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x0, 0x8, 0x10,
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0x18, 0x20, 0x28, 0x30, 0x38, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45,
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0x46, 0x47, 0x40, 0x48, 0x50, 0x58, 0x60, 0x68, 0x70, 0x78, 0x80,
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0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x80, 0x88, 0x90, 0x98,
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0xa0, 0xa8, 0xb0, 0xb8, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6,
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0xc7, 0xc0, 0xc8, 0xd0, 0xd8, 0xe0, 0xe8, 0xf0, 0xf8,
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};
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const uint8_t kOpMap0[] = {
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
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30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44,
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45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,
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60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74,
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75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89,
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90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104,
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105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119,
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120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134,
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135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149,
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150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164,
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165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179,
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180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194,
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195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209,
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210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223, 224,
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225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237, 238, 239,
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240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251, 252, 253, 254,
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255,
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};
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void WriteOp(int fd, struct XedDecodedInst *xedd) {
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int i;
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char buf[128], *p;
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p = stpcpy(buf, ".byte ");
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for (i = 0; i < xedd->length; ++i) {
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if (i) *p++ = ',';
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*p++ = '0';
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*p++ = 'x';
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*p++ = "0123456789abcdef"[(xedd->bytes[i] & 0xf0) >> 4];
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*p++ = "0123456789abcdef"[xedd->bytes[i] & 0x0f];
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}
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*p++ = '\n';
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CHECK_NE(-1, write(fd, buf, p - buf));
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}
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int main(int argc, char *argv[]) {
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int i, j, k, l, m, n, p, o, fd;
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uint8_t op[16];
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struct XedDecodedInst xedd[1];
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fd = open("/tmp/ops.s", O_CREAT | O_TRUNC | O_RDWR, 0644);
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for (o = 0; o < ARRAYLEN(kOpMap0); ++o) {
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for (p = 0; p < ARRAYLEN(kPrefixes); ++p) {
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memset(op, 0x55, 16);
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n = strlen(kPrefixes[p]);
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memcpy(op, kPrefixes[p], n);
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op[n] = kOpMap0[o];
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xed_decoded_inst_zero_set_mode(xedd, XED_MACHINE_MODE_LONG_64);
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if (!xed_instruction_length_decode(xedd, op, XED_MAX_INSTRUCTION_BYTES)) {
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if (xedd->op.has_modrm && xedd->op.has_sib) {
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for (i = 0; i < ARRAYLEN(kModrmPicks); ++i) {
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for (j = 0; j < ARRAYLEN(kModrmPicks); ++j) {
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memset(op, 0x55, 16);
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n = strlen(kPrefixes[p]);
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memcpy(op, kPrefixes[p], n);
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op[n] = kOpMap0[o];
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op[xedd->op.pos_modrm] = kModrmPicks[i];
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op[xedd->op.pos_sib] = kModrmPicks[j];
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xed_decoded_inst_zero_set_mode(xedd, XED_MACHINE_MODE_LONG_64);
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if (!xed_instruction_length_decode(xedd, op,
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XED_MAX_INSTRUCTION_BYTES)) {
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WriteOp(fd, xedd);
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}
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}
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}
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} else if (xedd->op.has_modrm) {
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for (i = 0; i < ARRAYLEN(kModrmPicks); ++i) {
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memset(op, 0x55, 16);
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n = strlen(kPrefixes[p]);
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memcpy(op, kPrefixes[p], n);
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op[n] = kOpMap0[o];
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op[xedd->op.pos_modrm] = kModrmPicks[i];
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xed_decoded_inst_zero_set_mode(xedd, XED_MACHINE_MODE_LONG_64);
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if (!xed_instruction_length_decode(xedd, op,
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XED_MAX_INSTRUCTION_BYTES)) {
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WriteOp(fd, xedd);
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}
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}
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} else {
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WriteOp(fd, xedd);
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}
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}
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}
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}
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close(fd);
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system("as -o /tmp/ops.o /tmp/ops.s");
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system("objdump -wd /tmp/ops.o |"
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" grep -v data16 |"
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" grep -v addr32 |"
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" grep -v '(bad)' |"
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" sed 's/^[ :[:xdigit:]]*//' |"
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" sed 's/^[ :[:xdigit:]]*//' |"
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" sed 's/[[:space:]]#.*$//' |"
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" grep -v 'rex\\.' |"
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" sort -u");
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return 0;
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}
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