mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-07 23:13:34 +00:00
2d80bbc802
blinkenlights now does a pretty good job emulating what happens when binaries boot from BIOS into long mode. So it's been much easier to debug the bare metal process and wrinkle out many issues.
98 lines
3.5 KiB
C
98 lines
3.5 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/struct/iovec.h"
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#include "libc/nexgen32e/uart.h"
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#include "libc/sysv/consts/fileno.h"
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#include "tool/build/lib/ioports.h"
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static int OpE9Read(struct Machine *m) {
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int fd;
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uint8_t b;
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fd = STDIN_FILENO;
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if (fd >= m->fds.i) return -1;
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if (!m->fds.p[fd].cb) return -1;
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if (m->fds.p[fd].cb->readv(m->fds.p[fd].fd, &(struct iovec){&b, 1}, 1) == 1) {
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return b;
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} else {
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return -1;
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}
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}
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static void OpE9Write(struct Machine *m, uint8_t b) {
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int fd;
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fd = STDOUT_FILENO;
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if (fd >= m->fds.i) return;
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if (!m->fds.p[fd].cb) return;
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m->fds.p[fd].cb->writev(m->fds.p[fd].fd, &(struct iovec){&b, 1}, 1);
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}
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static int OpSerialIn(struct Machine *m, int r) {
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switch (r) {
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case UART_DLL:
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if (!m->dlab) {
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return OpE9Read(m);
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} else {
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return 0x01;
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}
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case UART_LSR:
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return UART_TTYDA | UART_TTYTXR | UART_TTYIDL;
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default:
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return 0;
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}
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}
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static void OpSerialOut(struct Machine *m, int r, uint32_t x) {
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switch (r) {
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case UART_DLL:
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if (!m->dlab) {
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return OpE9Write(m, x);
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}
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break;
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case UART_LCR:
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m->dlab = !!(x & UART_DLAB);
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break;
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default:
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break;
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}
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}
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uint64_t OpIn(struct Machine *m, uint16_t p) {
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switch (p) {
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case 0xE9:
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return OpE9Read(m);
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case 0x3F8 ... 0x3FF:
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return OpSerialIn(m, p - 0x3F8);
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default:
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return -1;
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}
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}
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void OpOut(struct Machine *m, uint16_t p, uint32_t x) {
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switch (p) {
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case 0xE9:
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OpE9Write(m, x);
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break;
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case 0x3F8 ... 0x3FF:
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OpSerialOut(m, p - 0x3F8, x);
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break;
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default:
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break;
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}
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}
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