src/arch/i386/core/video_subr.c

   1 /*
   2  *
   3  * modified from linuxbios code
   4  * by Cai Qiang <rimy2000@hotmail.com>
   5  *
   6  */
   7
   8 #include "stddef.h"
   9 #include "string.h"
  10 #include <gpxe/io.h>
  11 #include "console.h"
  12 #include <gpxe/init.h>
  13 #include "vga.h"
  14
  15 struct console_driver vga_console;
  16
  17 static char *vidmem;            /* The video buffer */
  18 static int video_line, video_col;
  19
  20 #define VIDBUFFER 0xB8000
  21
  22 static void memsetw(void *s, int c, unsigned int n)
  23 {
  24         unsigned int i;
  25         u16 *ss = (u16 *) s;
  26
  27         for (i = 0; i < n; i++) {
  28                 ss[i] = ( u16 ) c;
  29         }
  30 }
  31
  32 static void video_init(void)
  33 {
  34         static int inited=0;
  35
  36         vidmem = (char *)phys_to_virt(VIDBUFFER);
  37
  38         if (!inited) {
  39                 video_line = 0;
  40                 video_col = 0;
  41
  42                 memsetw(vidmem, VGA_ATTR_CLR_WHT, 2*1024); //
  43
  44                 inited=1;
  45         }
  46 }
  47
  48 static void video_scroll(void)
  49 {
  50         int i;
  51
  52         memcpy(vidmem, vidmem + COLS * 2, (LINES - 1) * COLS * 2);
  53         for (i = (LINES - 1) * COLS * 2; i < LINES * COLS * 2; i += 2)
  54                 vidmem[i] = ' ';
  55 }
  56
  57 static void vga_putc(int byte)
  58 {
  59         if (byte == '\n') {
  60                 video_line++;
  61                 video_col = 0;
  62
  63         } else if (byte == '\r') {
  64                 video_col = 0;
  65
  66         } else if (byte == '\b') {
  67                 video_col--;
  68
  69         } else if (byte == '\t') {
  70                 video_col += 4;
  71
  72         } else if (byte == '\a') {
  73                 //beep
  74                 //beep(500);
  75
  76         } else {
  77                 vidmem[((video_col + (video_line *COLS)) * 2)] = byte;
  78                 vidmem[((video_col + (video_line *COLS)) * 2) +1] = VGA_ATTR_CLR_WHT;
  79                 video_col++;
  80         }
  81         if (video_col < 0) {
  82                 video_col = 0;
  83         }
  84         if (video_col >= COLS) {
  85                 video_line++;
  86                 video_col = 0;
  87         }
  88         if (video_line >= LINES) {
  89                 video_scroll();
  90                 video_line--;
  91         }
  92         // move the cursor
  93         write_crtc((video_col + (video_line *COLS)) >> 8, CRTC_CURSOR_HI);
  94         write_crtc((video_col + (video_line *COLS)) & 0x0ff, CRTC_CURSOR_LO);
  95 }
  96
  97 struct console_driver vga_console __console_driver = {
  98         .putchar = vga_putc,
  99         .disabled = 1,
 100 };
 101
 102 struct init_fn video_init_fn __init_fn ( INIT_EARLY ) = {
 103         .initialise = video_init,
 104 };