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Add VGA support on bare metal (#588)

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If your main module has this declaration:

    STATIC_YOINK("vga_console");

Then a VGA driver will be linked into your executable which
displays your stdio characters on the PC display, whereas
before we could only use the serial port. Your display is an
ANSI terminal and it's still a work in progress.
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tkchia 2022-09-07 09:41:08 +08:00 • committed by GitHub
parent 598640864a
commit 3fdb1c14f1
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11 changed files with 1556 additions and 5 deletions
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libc/vga/writev-vga.c Normal file
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/*-*- 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│
╞══════════════════════════════════════════════════════════════════════════════╡
│ This is free and unencumbered software released into the public domain. │
│ │
│ Anyone is free to copy, modify, publish, use, compile, sell, or │
│ distribute this software, either in source code form or as a compiled │
│ binary, for any purpose, commercial or non-commercial, and by any │
│ means. │
│ │
│ In jurisdictions that recognize copyright laws, the author or authors │
│ of this software dedicate any and all copyright interest in the │
│ software to the public domain. We make this dedication for the benefit │
│ of the public at large and to the detriment of our heirs and │
│ successors. We intend this dedication to be an overt act of │
│ relinquishment in perpetuity of all present and future rights to this │
│ software under copyright law. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, │
│ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF │
│ MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. │
│ IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR │
│ OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, │
│ ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR │
│ OTHER DEALINGS IN THE SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/struct/fd.internal.h"
#include "libc/calls/struct/iovec.h"
#include "libc/calls/struct/iovec.internal.h"
#include "libc/vga/vga.internal.h"
#include "libc/runtime/pc.internal.h"
#include "libc/str/str.h"
static struct Tty vga_tty;
#ifdef VGA_USE_WCS
static wchar_t vga_wcs[VGA_TTY_HEIGHT * VGA_TTY_WIDTH];
#else
static wchar_t * const vga_wcs = NULL;
#endif
ssize_t sys_writev_vga(struct Fd *fd, const struct iovec *iov, int iovlen) {
size_t i, wrote = 0;
ssize_t res = 0;
for (i = 0; i < iovlen; ++i) {
void *input = iov[i].iov_base;
size_t len = iov[i].iov_len;
res = _TtyWrite(&vga_tty, input, len);
if (res < 0)
break;
wrote += res;
if (res != len)
return wrote;
}
if (!wrote)
return res;
return wrote;
}
__attribute__((__constructor__)) static textstartup void _vga_init(void) {
void * const vid_buf = (void *)(BANE + 0xb8000ull);
/* Get the initial cursor position from the BIOS data area. */
typedef struct {
unsigned char col, row;
} bios_curs_pos_t;
bios_curs_pos_t pos = *(bios_curs_pos_t *)(BANE + 0x0450ull);
/*
* Initialize our tty structure from the current screen contents & current
* cursor position.
*/
_StartTty(&vga_tty, VGA_TTY_HEIGHT, VGA_TTY_WIDTH, pos.row, pos.col,
vid_buf, vga_wcs);
}