1;; ----------------------------------------------------------------------- 2;; 3;; Copyright 1994-2008 H. Peter Anvin - All Rights Reserved 4;; 5;; This program is free software; you can redistribute it and/or modify 6;; it under the terms of the GNU General Public License as published by 7;; the Free Software Foundation, Inc., 53 Temple Place Ste 330, 8;; Boston MA 02111-1307, USA; either version 2 of the License, or 9;; (at your option) any later version; incorporated herein by reference. 10;; 11;; ----------------------------------------------------------------------- 12 13;; 14;; font.inc 15;; 16;; VGA font handling code 17;; 18 19 section .text16 20 21; 22; loadfont: Load a .psf font file and install it onto the VGA console 23; (if we're not on a VGA screen then ignore.) 24; The font is on top of the getc stack. 25; 26loadfont.err: jmp close ; Tailcall the close routine 27 28loadfont: 29 mov di,trackbuf 30 mov cx,4 31 call readc ; Read header 32 jc .err 33 34 mov ax,[trackbuf] ; Magic number 35 cmp ax,0436h 36 jne .err 37 38 mov al,[trackbuf+2] ; File mode 39 cmp al,5 ; Font modes 0-5 supported 40 ja .err 41 42 xor bx,bx 43 mov bh,[trackbuf+3] ; Height of font 44 cmp bh,2 ; VGA minimum 45 jb .err 46 cmp bh,32 ; VGA maximum 47 ja .err 48 49 ; Load the actual font 50 mov di,trackbuf 51 mov cx,bx ; Bytes = font height * 256 52 call readc 53 jc .err 54 55 call close 56 57 ; Copy to font buffer 58 mov si,trackbuf ; Start of font data 59 mov [VGAFontSize],bh 60 push es 61 mov cx,aux_seg 62 mov es,cx 63 mov di,aux.fontbuf 64 mov cx,bx 65 shr cx,2 66 rep movsd 67 pop es 68 69 mov [UserFont], byte 1 ; Set font flag 70 71; 72; use_font: 73; This routine activates whatever font happens to be in the 74; vgafontbuf, and updates the adjust_screen data. 75; Must be called with CS = DS 76; 77use_font: 78 test byte [UsingVGA], ~03h ; Nonstandard mode? 79 jz .modeok 80 call vgaclearmode 81 82.modeok: 83 test [UserFont], byte 1 ; Are we using a user-specified font? 84 jz adjust_screen ; If not, just do the normal stuff 85 86 push es 87 mov bp,aux_seg 88 mov es,bp 89 90 mov bp,aux.fontbuf ; ES:BP -> font 91 mov bh,[VGAFontSize] 92 xor bl,bl ; Needed by both INT 10h calls 93 94 test byte [UsingVGA], 01h ; Are we in graphics mode? 95 jz .text 96 97.graphics: 98 xor cx,cx 99 mov cl,bh ; CX = bytes/character 100 mov ax,[GXPixRows] 101 div cl ; Compute char rows per screen 102 mov dl,al 103 dec ax 104 mov [VidRows],al 105 mov ax,1121h ; Set user character table 106 int 10h 107 mov ax,[GXPixCols] 108 shr ax,3 ; 8 pixels/character 109 dec ax 110 mov [VidCols],al 111 pop es 112 ret ; No need to call adjust_screen 113 114.text: 115 mov cx,256 116 xor dx,dx 117 mov ax,1110h 118 int 10h ; Load into VGA RAM 119 pop es 120 121 xor bl,bl 122 mov ax,1103h ; Select page 0 123 int 10h 124 125; 126; adjust_screen: Set the internal variables associated with the screen size. 127; This is a subroutine in case we're loading a custom font. 128; 129adjust_screen: 130 pusha 131 mov al,[BIOS_vidrows] 132 and al,al 133 jnz vidrows_ok 134 mov al,24 ; No vidrows in BIOS, assume 25 135 ; (Remember: vidrows == rows-1) 136vidrows_ok: mov [VidRows],al 137 mov ah,0fh 138 int 10h ; Read video state 139 dec ah ; Store count-1 (same as rows) 140 mov [VidCols],ah 141 popa 142 ret 143 144 section .data16 145 alignz 2 146VGAFontSize dw 16 ; Defaults to 16 byte font 147UserFont db 0 ; Using a user-specified font 148 149 section .bss16 150 alignb 4 151GXPixCols resw 1 ; Graphics mode pixel columns 152GXPixRows resw 1 ; Graphics mode pixel rows 153