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;; -----------------------------------------------------------------------
;;
;; Copyright 1994-2006 H. Peter Anvin - All Rights Reserved
;;
;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, Inc., 53 Temple Place Ste 330,
;; Boston MA 02111-1307, USA; either version 2 of the License, or
;; (at your option) any later version; incorporated herein by reference.
;;
;; -----------------------------------------------------------------------
;;
;; font.inc
;;
;; VGA font handling code
;;
section .text
;
; loadfont: Load a .psf font file and install it onto the VGA console
; (if we're not on a VGA screen then ignore.) It is called with
; SI and DX:AX set by routine searchdir
;
loadfont:
mov bx,trackbuf ; The trackbuf is >= 16K; the part
mov cx,[BufSafe] ; of a PSF file we care about is no
call getfssec ; more than 8K+4 bytes
mov ax,[trackbuf] ; Magic number
cmp ax,0436h
jne lf_ret
mov al,[trackbuf+2] ; File mode
cmp al,5 ; Font modes 0-5 supported
ja lf_ret
mov bh,byte [trackbuf+3] ; Height of font
cmp bh,2 ; VGA minimum
jb lf_ret
cmp bh,32 ; VGA maximum
ja lf_ret
; Copy to font buffer
mov si,trackbuf+4 ; Start of font data
mov [VGAFontSize],bh
mov di,vgafontbuf
mov cx,(32*256) >> 2 ; Maximum size
rep movsd
mov [UserFont], byte 1 ; Set font flag
; Fall through to use_font
;
; use_font:
; This routine activates whatever font happens to be in the
; vgafontbuf, and updates the adjust_screen data.
; Must be called with CS = DS = ES
;
use_font:
test byte [UsingVGA], ~03h ; Nonstandard mode?
jz .modeok
call vgaclearmode
.modeok:
test [UserFont], byte 1 ; Are we using a user-specified font?
jz adjust_screen ; If not, just do the normal stuff
mov bp,vgafontbuf
mov bh,[VGAFontSize]
xor bl,bl ; Needed by both INT 10h calls
test byte [UsingVGA], 01h ; Are we in graphics mode?
jz .text
.graphics:
xor cx,cx
mov cl,bh ; CX = bytes/character
mov ax,[GXPixRows]
div cl ; Compute char rows per screen
mov dl,al
dec ax
mov [VidRows],al
mov ax,1121h ; Set user character table
int 10h
mov ax,[GXPixCols]
shr ax,3 ; 8 pixels/character
dec ax
mov [VidCols],al
.lf_ret: ret ; No need to call adjust_screen
.text:
mov cx,256
xor dx,dx
mov ax,1110h
int 10h ; Load into VGA RAM
xor bl,bl
mov ax,1103h ; Select page 0
int 10h
; Fall through to adjust_screen
lf_ret equ use_font.lf_ret
;
; adjust_screen: Set the internal variables associated with the screen size.
; This is a subroutine in case we're loading a custom font.
;
adjust_screen:
pusha
mov al,[BIOS_vidrows]
and al,al
jnz vidrows_ok
mov al,24 ; No vidrows in BIOS, assume 25
; (Remember: vidrows == rows-1)
vidrows_ok: mov [VidRows],al
mov ah,0fh
int 10h ; Read video state
dec ah ; Store count-1 (same as rows)
mov [VidCols],ah
popa
ret
; VGA font buffer at the end of memory (so loading a font works even
; in graphics mode, but don't put too much pressure on the .bss)
section .latebss
vgafontbuf resb 8192
section .data
align 2, db 0
VGAFontSize dw 16 ; Defaults to 16 byte font
UserFont db 0 ; Using a user-specified font
section .bss
alignb 4
GXPixCols resw 1 ; Graphics mode pixel columns
GXPixRows resw 1 ; Graphics mode pixel rows
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