core/font.c

   1 /*
   2  * -----------------------------------------------------------------------
   3  *
   4  *   Copyright 1994-2008 H. Peter Anvin - All Rights Reserved
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
   9  *   Boston MA 02111-1307, USA; either version 2 of the License, or
  10  *   (at your option) any later version; incorporated herein by reference.
  11  *
  12  * -----------------------------------------------------------------------
  13  *
  14  *
  15  * font.c
  16  *
  17  * VGA font handling code
  18  *
  19  */
  20
  21 #include <sys/io.h>
  22 #include <stdio.h>
  23 #include <fs.h>
  24
  25 #include "bios.h"
  26 #include "graphics.h"
  27 #include "core.h"
  28
  29 static __lowmem char fontbuf[8192];
  30
  31 extern uint8_t UserFont;
  32
  33 uint16_t GXPixCols = 1;         /* Graphics mode pixel columns */
  34 uint16_t GXPixRows = 1;         /* Graphics mode pixel rows */
  35
  36 /*
  37  * loadfont:    Load a .psf font file and install it onto the VGA console
  38  *              (if we're not on a VGA screen then ignore.)
  39  */
  40 void loadfont(const char *filename)
  41 {
  42         struct psfheader {
  43                 uint16_t magic;
  44                 uint8_t mode;
  45                 uint8_t height;
  46         } hdr;
  47         FILE *f;
  48         char *p;
  49         int i;
  50
  51         f = fopen(filename, "r");
  52         if (!f)
  53                 return;
  54
  55         p = trackbuf;
  56         /* Read header */
  57         if (_fread(&hdr, sizeof hdr, f) != sizeof hdr)
  58                 goto fail;
  59
  60         /* Magic number */
  61         if (hdr.magic != 0x0436)
  62                 goto fail;
  63
  64         /* File mode: font modes 0-5 supported */
  65         if (hdr.mode > 5)
  66                 goto fail;
  67
  68         /* VGA minimum/maximum */
  69         if (hdr.height < 2 || hdr.height > 32)
  70                 goto fail;
  71
  72         /* Load the actual font into the font buffer. */
  73         memset(fontbuf, 0, 256*32);
  74
  75         p = fontbuf;
  76         for (i = 0; i < 256; i++) {
  77                 if (_fread(p, hdr.height, f) != hdr.height)
  78                         goto fail;
  79                 p += 32;
  80         }
  81
  82         /* Loaded OK */
  83         VGAFontSize = hdr.height;
  84         UserFont = 1;           /* Set font flag */
  85         use_font();
  86
  87 fail:
  88         fclose(f);
  89 }
  90
  91 /*
  92  * use_font:
  93  *      This routine activates whatever font happens to be in the
  94  *      vgafontbuf, and updates the adjust_screen data.
  95  *      Must be called with CS = DS
  96  */
  97 void use_font(void)
  98 {
  99         com32sys_t ireg, oreg;
 100         uint8_t bytes = VGAFontSize;
 101
 102         /* Nonstandard mode? */
 103         if (UsingVGA & ~0x3)
 104                 syslinux_force_text_mode();
 105
 106         memset(&ireg, 0, sizeof(ireg));
 107
 108         ireg.es = SEG(fontbuf);
 109         ireg.ebp.w[0] = OFFS(fontbuf); /* ES:BP -> font */
 110
 111         /* Are we using a user-specified font? */
 112         if (UserFont & 0x1) {
 113                 /* Are we in graphics mode? */
 114                 if (UsingVGA & 0x1) {
 115                         uint8_t rows;
 116
 117                         rows = GXPixRows / bytes;
 118                         VidRows = rows - 1;
 119
 120                         /* Set user character table */
 121                         ireg.eax.w[0] = 0x1121;
 122                         ireg.ebx.b[0] = 0;
 123                         ireg.ecx.b[0] = bytes; /* bytes/character */
 124                         ireg.edx.b[0] = rows;
 125
 126                         __intcall(0x10, &ireg, &oreg);
 127
 128                         /* 8 pixels/character */
 129                         VidCols = ((GXPixCols >> 3) - 1);
 130
 131                         /* No need to call adjust_screen */
 132                         return;
 133                 } else {
 134                         ireg.eax.w[0] = 0x1110; /* Load into VGA RAM */
 135                         ireg.ebx.b[0] = 0;
 136                         ireg.ebx.b[1] = bytes; /* bytes/character */
 137                         ireg.ecx.w[0] = 256;
 138                         ireg.edx.w[0] = 0;
 139
 140                         __intcall(0x10, &ireg, &oreg);
 141
 142                         ireg.ebx.b[0] = 0;
 143                         ireg.eax.w[0] = 0x1103; /* Select page 0 */
 144                         __intcall(0x10, &ireg, NULL);
 145                 }
 146         }
 147
 148         adjust_screen();
 149 }
 150
 151 /*
 152  * adjust_screen: Set the internal variables associated with the screen size.
 153  *              This is a subroutine in case we're loading a custom font.
 154  */
 155 void adjust_screen(void)
 156 {
 157         com32sys_t ireg, oreg;
 158         volatile uint8_t *vidrows = (volatile uint8_t *)BIOS_vidrows;
 159         uint8_t rows, cols;
 160
 161         rows = *vidrows;
 162         if (!rows) {
 163                 /*
 164                  * No vidrows in BIOS, assume 25.
 165                  * (Remember: vidrows == rows-1)
 166                  */
 167                 rows = 24;
 168         }
 169
 170         VidRows = rows;
 171
 172         ireg.eax.b[1] = 0x0f;   /* Read video state */
 173         __intcall(0x10, &ireg, &oreg);
 174         cols = oreg.eax.b[1];
 175
 176         VidCols = --cols;       /* Store count-1 (same as rows) */
 177 }
 178
 179 void pm_adjust_screen(com32sys_t *regs __unused)
 180 {
 181         adjust_screen();
 182 }
 183
 184 void pm_userfont(com32sys_t *regs)
 185 {
 186         regs->es = SEG(fontbuf);
 187         regs->ebx.w[0] = OFFS(fontbuf);
 188 }