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 <sys/io.h>
  24 #include <stdio.h>
  25 #include <fs.h>
  26
  27 #include "bios.h"
  28 #include "graphics.h"
  29 #include "core.h"
  30
  31 __export uint8_t UserFont = 0;          /* Using a user-specified font */
  32
  33 __export __lowmem char fontbuf[8192];
  34
  35 uint16_t GXPixCols = 1;         /* Graphics mode pixel columns */
  36 uint16_t GXPixRows = 1;         /* Graphics mode pixel rows */
  37
  38 /*
  39  * loadfont:    Load a .psf font file and install it onto the VGA console
  40  *              (if we're not on a VGA screen then ignore.)
  41  */
  42 __export void loadfont(const char *filename)
  43 {
  44         struct psfheader {
  45                 uint16_t magic;
  46                 uint8_t mode;
  47                 uint8_t height;
  48         } hdr;
  49         FILE *f;
  50
  51         f = fopen(filename, "r");
  52         if (!f)
  53                 return;
  54
  55         /* Read header */
  56         if (_fread(&hdr, sizeof hdr, f) != sizeof hdr)
  57                 goto fail;
  58
  59         /* Magic number */
  60         if (hdr.magic != 0x0436)
  61                 goto fail;
  62
  63         /* File mode: font modes 0-5 supported */
  64         if (hdr.mode > 5)
  65                 goto fail;
  66
  67         /* VGA minimum/maximum */
  68         if (hdr.height < 2 || hdr.height > 32)
  69                 goto fail;
  70
  71         /* Load the actual font into the font buffer. */
  72         memset(fontbuf, 0, 256*32);
  73         if (_fread(fontbuf, 256*hdr.height, f) != 256*hdr.height)
  74             goto fail;
  75
  76         /* Loaded OK */
  77         VGAFontSize = hdr.height;
  78         UserFont = 1;           /* Set font flag */
  79         use_font();
  80
  81 fail:
  82         fclose(f);
  83 }
  84
  85 /*
  86  * use_font:
  87  *      This routine activates whatever font happens to be in the
  88  *      vgafontbuf, and updates the bios_adjust_screen data.
  89  *      Must be called with CS = DS
  90  */
  91 void use_font(void)
  92 {
  93         com32sys_t ireg, oreg;
  94         uint8_t bytes = VGAFontSize;
  95
  96         /* Nonstandard mode? */
  97         if (UsingVGA & ~0x3)
  98                 syslinux_force_text_mode();
  99
 100         memset(&ireg, 0, sizeof(ireg));
 101
 102         ireg.es = SEG(fontbuf);
 103         ireg.ebp.w[0] = OFFS(fontbuf); /* ES:BP -> font */
 104
 105         /* Are we using a user-specified font? */
 106         if (UserFont & 0x1) {
 107                 /* Are we in graphics mode? */
 108                 if (UsingVGA & 0x1) {
 109                         uint8_t rows;
 110
 111                         rows = GXPixRows / bytes;
 112                         VidRows = rows - 1;
 113
 114                         /* Set user character table */
 115                         ireg.eax.w[0] = 0x1121;
 116                         ireg.ebx.b[0] = 0;
 117                         ireg.ecx.b[0] = bytes; /* bytes/character */
 118                         ireg.edx.b[0] = rows;
 119
 120                         __intcall(0x10, &ireg, &oreg);
 121
 122                         /* 8 pixels/character */
 123                         VidCols = ((GXPixCols >> 3) - 1);
 124
 125                         /* No need to call bios_adjust_screen */
 126                         return;
 127                 } else {
 128                         ireg.eax.w[0] = 0x1110; /* Load into VGA RAM */
 129                         ireg.ebx.b[0] = 0;
 130                         ireg.ebx.b[1] = bytes; /* bytes/character */
 131                         ireg.ecx.w[0] = 256;
 132                         ireg.edx.w[0] = 0;
 133
 134                         __intcall(0x10, &ireg, &oreg);
 135
 136                         ireg.ebx.b[0] = 0;
 137                         ireg.eax.w[0] = 0x1103; /* Select page 0 */
 138                         __intcall(0x10, &ireg, NULL);
 139                 }
 140
 141         }
 142
 143         bios_adjust_screen();
 144 }
 145
 146 /*
 147  * bios_adjust_screen: Set the internal variables associated with the screen size.
 148  *              This is a subroutine in case we're loading a custom font.
 149  */
 150 void bios_adjust_screen(void)
 151 {
 152         com32sys_t ireg, oreg;
 153         volatile uint8_t *vidrows = (volatile uint8_t *)BIOS_vidrows;
 154         uint8_t rows, cols;
 155
 156         rows = *vidrows;
 157         if (!rows) {
 158                 /*
 159                  * No vidrows in BIOS, assume 25.
 160                  * (Remember: vidrows == rows-1)
 161                  */
 162                 rows = 24;
 163         }
 164
 165         VidRows = rows;
 166
 167         ireg.eax.b[1] = 0x0f;   /* Read video state */
 168         __intcall(0x10, &ireg, &oreg);
 169         cols = oreg.eax.b[1];
 170
 171         VidCols = --cols;       /* Store count-1 (same as rows) */
 172 }
 173
 174 void adjust_screen(void)
 175 {
 176         if (firmware->adjust_screen)
 177                 firmware->adjust_screen();
 178 }
 179
 180 void pm_adjust_screen(com32sys_t *regs __unused)
 181 {
 182         adjust_screen();
 183 }
 184
 185 void pm_userfont(com32sys_t *regs)
 186 {
 187         regs->es = SEG(fontbuf);
 188         regs->ebx.w[0] = OFFS(fontbuf);
 189 }