More common code factoring: getc library, font handling code

1 files changed, 117 insertions, 0 deletions

diff --git a/font.inc b/font.inc
new file mode 100644
index 00000000..bc1c5b10
--- /dev/null
+++ b/font.inc
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+;; $Id$
+;; -----------------------------------------------------------------------
+;;   
+;;   Copyright 1994-2002 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,
+;;   Bostom 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
+;;
+
+;
+; 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 [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
+		cmp [UsingVGA], byte 1		; Are we in graphics mode?
+		jne .text
+
+.graphics:
+		xor cx,cx
+		mov cl,bh			; CX = bytes/character
+		mov ax,480
+		div cl				; Compute char rows per screen
+		mov dl,al
+		dec al
+		mov [VidRows],al
+		mov ax,1121h			; Set user character table
+		int 10h
+		mov [VidCols], byte 79		; Always 80 bytes/line
+		mov [TextPage], byte 0		; Always page 0
+.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:
+                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
+                mov [TextPage],bh
+                dec ah                          ; Store count-1 (same as rows)
+                mov [VidCols],ah
+		ret
+