cosmopolitan/libc/calls/readv-serial.c
Justine Tunney 933411ba99 Improve synchronization
- Fix bugs in kDos2Errno definition
- malloc() should now be thread safe
- Fix bug in rollup.com header generator
- Fix open(O_APPEND) on the New Technology
- Fix select() on the New Technology and test it
- Work towards refactoring i/o for thread safety
- Socket reads and writes on NT now poll for signals
- Work towards i/o completion ports on the New Technology
- Make read() and write() intermittently check for signals
- Blinkenlights keyboard i/o so much better on NT w/ poll()
- You can now poll() files and sockets at the same time on NT
- Fix bug in appendr() that manifests with dlmalloc footers off
2022-04-15 15:31:55 -07:00

48 lines
2.5 KiB
C

/*-*- 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/calls/internal.h"
#include "libc/nexgen32e/uart.internal.h"
#include "libc/runtime/pc.internal.h"
static bool IsDataAvailable(struct Fd *fd) {
return inb(fd->handle + UART_LSR) & UART_TTYDA;
}
static int GetFirstIov(struct iovec *iov, int iovlen) {
int i;
for (i = 0; i < iovlen; ++i) {
if (iov[i].iov_len) {
return i;
}
}
return -1;
}
ssize_t sys_readv_serial(struct Fd *fd, const struct iovec *iov, int iovlen) {
size_t i;
if ((i = GetFirstIov(iov, iovlen)) != -1) {
while (!IsDataAvailable(fd)) {
__builtin_ia32_pause();
}
((char *)iov[i].iov_base)[0] = inb(fd->handle);
return 1;
} else {
return 0;
}
}