core/font.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 1994-2008 H. Peter Anvin - All Rights Reserved
   4  *   Copyright 2013 Intel Corporation
   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  *
  16  * font.c
  17  *
  18  * VGA font handling code
  19  *
  20  */
  21
  22 #include <syslinux/firmware.h>
  23 #include <syslinux/video.h>
  24 #include <sys/io.h>
  25 #include <stdio.h>
  26 #include <fs.h>
  27
  28 #include "bios.h"
  29 #include "graphics.h"
  30 #include "core.h"
  31
  32 __export uint8_t UserFont = 0;          /* Using a user-specified font */
  33
  34 __export __lowmem char fontbuf[8192];
  35
  36 uint16_t GXPixCols = 1;         /* Graphics mode pixel columns */
  37 uint16_t GXPixRows = 1;         /* Graphics mode pixel rows */
  38
  39 /*
  40  * loadfont:    Load a .psf font file and install it onto the VGA console
  41  *              (if we're not on a VGA screen then ignore.)
  42  */
  43 __export void loadfont(const char *filename)
  44 {
  45         struct psfheader {
  46                 uint16_t magic;
  47                 uint8_t mode;
  48                 uint8_t height;
  49         } hdr;
  50         FILE *f;
  51
  52         f = fopen(filename, "r");
  53         if (!f)
  54                 return;
  55
  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         if (_fread(fontbuf, 256*hdr.height, f) != 256*hdr.height)
  75             goto fail;
  76
  77         /* Loaded OK */
  78         VGAFontSize = hdr.height;
  79         UserFont = 1;           /* Set font flag */
  80         use_font();
  81
  82 fail:
  83         fclose(f);
  84 }
  85
  86 /*
  87  * use_font:
  88  *      This routine activates whatever font happens to be in the
  89  *      vgafontbuf, and updates the bios_adjust_screen data.
  90  *      Must be called with CS = DS
  91  */
  92 void use_font(void)
  93 {
  94         com32sys_t ireg, oreg;
  95         uint8_t bytes = VGAFontSize;
  96
  97         /* Nonstandard mode? */
  98         if (UsingVGA & ~0x3)
  99                 syslinux_force_text_mode();
 100
 101         memset(&ireg, 0, sizeof(ireg));
 102
 103         ireg.es = SEG(fontbuf);
 104         ireg.ebp.w[0] = OFFS(fontbuf); /* ES:BP -> font */
 105
 106         /* Are we using a user-specified font? */
 107         if (UserFont & 0x1) {
 108                 /* Are we in graphics mode? */
 109                 if (UsingVGA & 0x1) {
 110                         uint8_t rows;
 111
 112                         rows = GXPixRows / bytes;
 113                         VidRows = rows - 1;
 114
 115                         /* Set user character table */
 116                         ireg.eax.w[0] = 0x1121;
 117                         ireg.ebx.b[0] = 0;
 118                         ireg.ecx.b[0] = bytes; /* bytes/character */
 119                         ireg.edx.b[0] = rows;
 120
 121                         __intcall(0x10, &ireg, &oreg);
 122
 123                         /* 8 pixels/character */
 124                         VidCols = ((GXPixCols >> 3) - 1);
 125
 126                         /* No need to call bios_adjust_screen */
 127                         return;
 128                 } else {
 129                         ireg.eax.w[0] = 0x1110; /* Load into VGA RAM */
 130                         ireg.ebx.b[0] = 0;
 131                         ireg.ebx.b[1] = bytes; /* bytes/character */
 132                         ireg.ecx.w[0] = 256;
 133                         ireg.edx.w[0] = 0;
 134
 135                         __intcall(0x10, &ireg, &oreg);
 136
 137                         memset(&ireg, 0, sizeof(ireg));
 138                         ireg.ebx.b[0] = 0;
 139                         ireg.eax.w[0] = 0x1103; /* Select page 0 */
 140                         __intcall(0x10, &ireg, NULL);
 141                 }
 142
 143         }
 144
 145         bios_adjust_screen();
 146 }
 147
 148 /*
 149  * bios_adjust_screen: Set the internal variables associated with the screen size.
 150  *              This is a subroutine in case we're loading a custom font.
 151  */
 152 void bios_adjust_screen(void)
 153 {
 154         com32sys_t ireg, oreg;
 155         volatile uint8_t *vidrows = (volatile uint8_t *)BIOS_vidrows;
 156         uint8_t rows, cols;
 157
 158         memset(&ireg, 0, sizeof(ireg));
 159
 160         rows = *vidrows;
 161         if (!rows) {
 162                 /*
 163                  * No vidrows in BIOS, assume 25.
 164                  * (Remember: vidrows == rows-1)
 165                  */
 166                 rows = 24;
 167         }
 168
 169         VidRows = rows;
 170
 171         ireg.eax.b[1] = 0x0f;   /* Read video state */
 172         __intcall(0x10, &ireg, &oreg);
 173         cols = oreg.eax.b[1];
 174
 175         VidCols = --cols;       /* Store count-1 (same as rows) */
 176 }
 177
 178 void adjust_screen(void)
 179 {
 180         if (firmware->adjust_screen)
 181                 firmware->adjust_screen();
 182 }
 183
 184 void pm_adjust_screen(com32sys_t *regs __unused)
 185 {
 186         adjust_screen();
 187 }
 188
 189 void pm_userfont(com32sys_t *regs)
 190 {
 191         regs->es = SEG(fontbuf);
 192         regs->ebx.w[0] = OFFS(fontbuf);
 193 }