mirror of
https://github.com/jart/cosmopolitan.git
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85 lines
3.6 KiB
C
85 lines
3.6 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 2021 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/internal.h"
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#include "libc/intrin/safemacros.internal.h"
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#include "libc/nexgen32e/rdtsc.h"
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#include "libc/nexgen32e/uart.internal.h"
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#include "libc/runtime/pc.internal.h"
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#include "libc/sock/internal.h"
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#include "libc/sock/struct/pollfd.h"
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#include "libc/sysv/consts/poll.h"
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#ifdef __x86_64__
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int sys_poll_metal(struct pollfd *fds, size_t nfds, unsigned timeout_ms) {
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int rc;
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size_t i;
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bool blocking;
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uint64_t start, timeout;
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if (!timeout_ms) {
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start = 0;
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timeout = 0;
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blocking = false;
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} else {
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start = rdtsc();
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timeout = timeout_ms;
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timeout *= 3; /* approx. cycles to nanoseconds */
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timeout *= 1000000;
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blocking = true;
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}
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for (rc = 0;;) {
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for (i = 0; i < nfds; ++i) {
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fds[i].revents = 0;
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if (fds[i].fd >= 0) {
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if (__isfdopen(fds[i].fd)) {
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switch (g_fds.p[fds[i].fd].kind) {
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case kFdSerial:
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if ((fds[i].events & POLLIN) &&
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(inb(g_fds.p[fds[i].fd].handle + UART_LSR) & UART_TTYDA)) {
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fds[i].revents |= POLLIN;
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}
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if ((fds[i].events & POLLOUT) &&
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(inb(g_fds.p[fds[i].fd].handle + UART_LSR) & UART_TTYTXR)) {
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fds[i].revents |= POLLOUT;
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}
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break;
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case kFdFile:
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if (fds[i].events & (POLLIN | POLLOUT)) {
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fds[i].revents |= fds[i].events & (POLLIN | POLLOUT);
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}
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break;
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default:
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fds[i].revents = POLLNVAL;
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break;
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}
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} else {
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fds[i].revents = POLLNVAL;
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}
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}
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if (fds[i].revents) ++rc;
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}
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if (rc || !blocking || unsignedsubtract(rdtsc(), start) >= timeout) {
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break;
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} else {
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__builtin_ia32_pause();
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}
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}
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return rc;
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}
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#endif
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