2 ;; -----------------------------------------------------------------------
4 ;; Copyright 1994-2004 H. Peter Anvin - All Rights Reserved
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.
12 ;; -----------------------------------------------------------------------
17 ;; VGA font handling code
23 ; loadfont: Load a .psf font file and install it onto the VGA console
24 ; (if we're not on a VGA screen then ignore.) It is called with
25 ; SI and DX:AX set by routine searchdir
28 mov bx,trackbuf ; The trackbuf is >= 16K; the part
29 mov cx,[BufSafe] ; of a PSF file we care about is no
30 call getfssec ; more than 8K+4 bytes
32 mov ax,[trackbuf] ; Magic number
36 mov al,[trackbuf+2] ; File mode
37 cmp al,5 ; Font modes 0-5 supported
40 mov bh,byte [trackbuf+3] ; Height of font
41 cmp bh,2 ; VGA minimum
43 cmp bh,32 ; VGA maximum
47 mov si,trackbuf+4 ; Start of font data
50 mov cx,(32*256) >> 2 ; Maximum size
53 mov [UserFont], byte 1 ; Set font flag
55 ; Fall through to use_font
59 ; This routine activates whatever font happens to be in the
60 ; vgafontbuf, and updates the adjust_screen data.
61 ; Must be called with CS = DS = ES
64 test [UserFont], byte 1 ; Are we using a user-specified font?
65 jz adjust_screen ; If not, just do the normal stuff
70 xor bl,bl ; Needed by both INT 10h calls
71 cmp [UsingVGA], byte 1 ; Are we in graphics mode?
76 mov cl,bh ; CX = bytes/character
78 div cl ; Compute char rows per screen
82 mov ax,1121h ; Set user character table
84 mov [VidCols], byte 79 ; Always 80 bytes/line
85 .lf_ret: ret ; No need to call adjust_screen
91 int 10h ; Load into VGA RAM
94 mov ax,1103h ; Select page 0
97 ; Fall through to adjust_screen
99 lf_ret equ use_font.lf_ret
102 ; adjust_screen: Set the internal variables associated with the screen size.
103 ; This is a subroutine in case we're loading a custom font.
107 mov al,[BIOS_vidrows]
110 mov al,24 ; No vidrows in BIOS, assume 25
111 ; (Remember: vidrows == rows-1)
112 vidrows_ok: mov [VidRows],al
114 int 10h ; Read video state
115 dec ah ; Store count-1 (same as rows)
121 ; VGA font buffer at the end of memory (so loading a font works even
122 ; in graphics mode, but don't put too much pressure on the .bss)
128 VGAFontSize dw 16 ; Defaults to 16 byte font
129 UserFont db 0 ; Using a user-specified font