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https://github.com/jart/cosmopolitan.git
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Add x86_64-linux-gnu emulator
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
This commit is contained in:
Justine Tunney
parent
467504308a
commit
f4f4caab0e
1052 changed files with 65667 additions and 7825 deletions
271
tool/build/lib/divmul.c
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271
tool/build/lib/divmul.c
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/*-*- 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/limits.h"
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#include "libc/log/log.h"
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#include "tool/build/lib/divmul.h"
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#include "tool/build/lib/endian.h"
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#include "tool/build/lib/flags.h"
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#include "tool/build/lib/modrm.h"
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#include "tool/build/lib/throw.h"
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void OpDivAlAhAxEbSigned(struct Machine *m) {
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int8_t y, rem;
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int16_t x, quo;
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x = Read16(m->ax);
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y = Read8(GetModrmRegisterBytePointerRead(m));
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if (!y || (x == INT16_MIN && y < 0)) ThrowDivideError(m);
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quo = x / y;
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rem = x % y;
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if (!(INT8_MIN <= quo && quo <= INT8_MAX)) ThrowDivideError(m);
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m->ax[0] = quo & 0xff;
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m->ax[1] = rem & 0xff;
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}
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void OpDivAlAhAxEbUnsigned(struct Machine *m) {
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uint8_t y, rem;
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uint16_t x, quo;
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x = Read16(m->ax);
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y = Read8(GetModrmRegisterBytePointerRead(m));
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if (!y) ThrowDivideError(m);
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quo = x / y;
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rem = x % y;
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if (!(UINT8_MIN <= quo && quo <= UINT8_MAX)) ThrowDivideError(m);
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m->ax[0] = quo & 0xff;
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m->ax[1] = rem & 0xff;
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}
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static void OpDivRdxRaxEvqpSigned64(struct Machine *m, uint8_t *p) {
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int64_t y, rem;
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int128_t x, quo;
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x = (uint128_t)Read64(m->dx) << 64 | Read64(m->ax);
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y = Read64(p);
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if (!y || (x == INT128_MIN && y < 0)) ThrowDivideError(m);
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quo = x / y;
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rem = x % y;
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if (!(INT64_MIN <= quo && quo <= INT64_MAX)) ThrowDivideError(m);
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Write64(m->ax, quo);
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Write64(m->dx, rem);
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}
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static void OpDivRdxRaxEvqpSigned32(struct Machine *m, uint8_t *p) {
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int32_t y, rem;
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int64_t x, quo;
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x = (uint64_t)Read32(m->dx) << 32 | Read32(m->ax);
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y = Read32(p);
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if (!y || (x == INT64_MIN && y < 0)) ThrowDivideError(m);
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quo = x / y;
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rem = x % y;
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if (!(INT32_MIN <= quo && quo <= INT32_MAX)) ThrowDivideError(m);
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Write64(m->ax, quo & 0xffffffff);
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Write64(m->dx, rem & 0xffffffff);
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}
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static void OpDivRdxRaxEvqpSigned16(struct Machine *m, uint8_t *p) {
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int16_t y, rem;
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int32_t x, quo;
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x = (uint32_t)Read16(m->dx) << 16 | Read16(m->ax);
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y = Read16(p);
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if (!y || (x == INT32_MIN && y < 0)) ThrowDivideError(m);
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quo = x / y;
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rem = x % y;
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if (!(INT16_MIN <= quo && quo <= INT16_MAX)) ThrowDivideError(m);
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Write16(m->ax, quo);
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Write16(m->dx, rem);
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}
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static void OpDivRdxRaxEvqpUnsigned16(struct Machine *m, uint8_t *p) {
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uint16_t y, rem;
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uint32_t x, quo;
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x = (uint32_t)Read16(m->dx) << 16 | Read16(m->ax);
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y = Read16(p);
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if (!y) ThrowDivideError(m);
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quo = x / y;
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rem = x % y;
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if (!(UINT16_MIN <= quo && quo <= UINT16_MAX)) ThrowDivideError(m);
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Write16(m->ax, quo);
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Write16(m->dx, rem);
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}
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static void OpDivRdxRaxEvqpUnsigned32(struct Machine *m, uint8_t *p) {
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uint32_t y, rem;
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uint64_t x, quo;
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x = (uint64_t)Read32(m->dx) << 32 | Read32(m->ax);
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y = Read32(p);
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if (!y) ThrowDivideError(m);
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quo = x / y;
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rem = x % y;
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if (!(UINT32_MIN <= quo && quo <= UINT32_MAX)) ThrowDivideError(m);
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Write64(m->ax, quo & 0xffffffff);
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Write64(m->dx, rem & 0xffffffff);
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}
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static void OpDivRdxRaxEvqpUnsigned64(struct Machine *m, uint8_t *p) {
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uint64_t y, rem;
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uint128_t x, quo;
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x = (uint128_t)Read64(m->dx) << 64 | Read64(m->ax);
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y = Read64(p);
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if (!y) ThrowDivideError(m);
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quo = x / y;
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rem = x % y;
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if (!(UINT64_MIN <= quo && quo <= UINT64_MAX)) ThrowDivideError(m);
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Write64(m->ax, quo);
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Write64(m->dx, rem);
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}
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void OpDivRdxRaxEvqpSigned(struct Machine *m) {
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uint8_t *p;
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p = GetModrmRegisterWordPointerReadOszRexw(m);
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if (Rexw(m->xedd)) {
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OpDivRdxRaxEvqpSigned64(m, p);
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} else if (!Osz(m->xedd)) {
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OpDivRdxRaxEvqpSigned32(m, p);
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} else {
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OpDivRdxRaxEvqpSigned16(m, p);
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}
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}
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void OpDivRdxRaxEvqpUnsigned(struct Machine *m) {
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uint8_t *p;
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p = GetModrmRegisterWordPointerReadOszRexw(m);
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if (Rexw(m->xedd)) {
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OpDivRdxRaxEvqpUnsigned64(m, p);
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} else if (!Osz(m->xedd)) {
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OpDivRdxRaxEvqpUnsigned32(m, p);
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} else {
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OpDivRdxRaxEvqpUnsigned16(m, p);
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}
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}
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void OpMulAxAlEbSigned(struct Machine *m) {
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bool of;
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int16_t ax;
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uint8_t *p;
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p = GetModrmRegisterBytePointerRead(m);
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__builtin_mul_overflow((int8_t)Read8(m->ax), (int8_t)Read8(p), &ax);
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of = (int)ax != (int8_t)ax;
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m->flags = SetFlag(m->flags, FLAGS_CF, of);
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m->flags = SetFlag(m->flags, FLAGS_OF, of);
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Write16(m->ax, ax);
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}
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void OpMulAxAlEbUnsigned(struct Machine *m) {
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int ax;
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bool of;
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uint8_t *p;
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p = GetModrmRegisterBytePointerRead(m);
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__builtin_mul_overflow(Read8(m->ax), Read8(p), &ax);
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of = (uint8_t)ax != ax;
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m->flags = SetFlag(m->flags, FLAGS_CF, of);
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m->flags = SetFlag(m->flags, FLAGS_OF, of);
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Write16(m->ax, ax);
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}
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void OpMulRdxRaxEvqpSigned(struct Machine *m) {
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bool of;
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uint8_t *p;
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int32_t dxax;
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int64_t edxeax;
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int128_t rdxrax;
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p = GetModrmRegisterWordPointerReadOszRexw(m);
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if (Rexw(m->xedd)) {
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__builtin_mul_overflow((int128_t)(int64_t)Read64(m->ax), (int64_t)Read64(p),
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&rdxrax);
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of = (int128_t)rdxrax != (int64_t)rdxrax;
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Write64(m->ax, rdxrax);
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Write64(m->dx, rdxrax >> 64);
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} else if (!Osz(m->xedd)) {
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__builtin_mul_overflow((int64_t)(int32_t)Read32(m->ax), (int32_t)Read32(p),
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&edxeax);
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of = (int64_t)edxeax != (int32_t)edxeax;
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Write64(m->ax, edxeax);
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Write64(m->dx, edxeax >> 32);
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} else {
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__builtin_mul_overflow((int32_t)(int16_t)Read16(m->ax), (int16_t)Read16(p),
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&dxax);
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of = (int32_t)dxax != (int16_t)dxax;
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Write16(m->ax, dxax);
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Write16(m->dx, dxax >> 16);
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}
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m->flags = SetFlag(m->flags, FLAGS_CF, of);
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m->flags = SetFlag(m->flags, FLAGS_OF, of);
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}
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void OpMulRdxRaxEvqpUnsigned(struct Machine *m) {
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bool of;
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uint8_t *p;
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uint32_t dxax;
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uint64_t edxeax;
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uint128_t rdxrax;
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p = GetModrmRegisterWordPointerReadOszRexw(m);
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if (Rexw(m->xedd)) {
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__builtin_mul_overflow((uint128_t)Read64(m->ax), Read64(p), &rdxrax);
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of = (uint64_t)rdxrax != rdxrax;
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Write64(m->ax, rdxrax);
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Write64(m->dx, rdxrax >> 64);
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} else if (!Osz(m->xedd)) {
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__builtin_mul_overflow((uint64_t)Read32(m->ax), Read32(p), &edxeax);
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of = (uint32_t)edxeax != edxeax;
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Write64(m->ax, edxeax);
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Write64(m->dx, edxeax >> 32);
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} else {
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__builtin_mul_overflow((uint32_t)(uint16_t)Read16(m->ax),
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(uint16_t)Read16(p), &dxax);
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of = (uint16_t)dxax != dxax;
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Write16(m->ax, dxax);
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Write16(m->dx, dxax >> 16);
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}
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m->flags = SetFlag(m->flags, FLAGS_CF, of);
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m->flags = SetFlag(m->flags, FLAGS_OF, of);
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}
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static void AluImul(struct Machine *m, uint8_t *a, uint8_t *b) {
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unsigned of;
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if (Rexw(m->xedd)) {
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int64_t x, y, z;
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x = Read64(a);
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y = Read64(b);
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of = __builtin_mul_overflow(x, y, &z);
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Write64(RegRexrReg(m), z);
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} else if (!Osz(m->xedd)) {
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int32_t x, y, z;
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x = Read32(a);
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y = Read32(b);
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of = __builtin_mul_overflow(x, y, &z);
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Write64(RegRexrReg(m), z & 0xffffffff);
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} else {
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int16_t x, y, z;
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x = Read16(a);
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y = Read16(b);
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of = __builtin_mul_overflow(x, y, &z);
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Write16(RegRexrReg(m), z);
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}
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m->flags = SetFlag(m->flags, FLAGS_CF, of);
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m->flags = SetFlag(m->flags, FLAGS_OF, of);
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}
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void OpImulGvqpEvqp(struct Machine *m) {
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AluImul(m, RegRexrReg(m), GetModrmRegisterWordPointerReadOszRexw(m));
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}
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void OpImulGvqpEvqpImm(struct Machine *m) {
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uint8_t b[8];
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Write64(b, m->xedd->op.uimm0);
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AluImul(m, GetModrmRegisterWordPointerReadOszRexw(m), b);
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}
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