More common code factoring: getc library, font handling code

1 files changed, 281 insertions, 0 deletions

diff --git a/getc.inc b/getc.inc
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index 00000000..5a807ebd
--- /dev/null
+++ b/getc.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.
+;;
+;; -----------------------------------------------------------------------
+
+;;
+;; getc.inc
+;;
+;; Simple file handling library (open, getc, ungetc)
+;;
+
+;
+; open,getc:	Load a file a character at a time for parsing in a manner
+;		similar to the C library getc routine.	Only one simultaneous
+;		use is supported.  Note: "open" trashes the trackbuf.
+;
+;		open:	Input:	mangled filename in DS:DI
+;			Output: ZF set on file not found or zero length
+;
+;		openfd:	Input:	file handle in SI
+;			Output:	none
+;
+;		getc:	Output: CF set on end of file
+;				Character loaded in AL
+;
+open:
+		call searchdir
+		jz open_return
+openfd:
+		pushf
+		mov [FBytes1],ax
+		mov [FBytes2],dx
+		add ax,[ClustSize]
+		adc dx,byte 0
+		sub ax,byte 1
+		sbb dx,byte 0
+		div word [ClustSize]
+		mov [FClust],ax		; Number of clusters
+		mov [FNextClust],si	; Cluster pointer
+		mov ax,[EndOfGetCBuf]	; Pointer at end of buffer ->
+		mov [FPtr],ax		;  nothing loaded yet
+		popf			; Restore no ZF
+open_return:	ret
+
+getc:
+		stc			; If we exit here -> EOF
+		mov ecx,[FBytes]
+		jecxz getc_ret
+		mov si,[FPtr]
+		cmp si,[EndOfGetCBuf]
+		jb getc_loaded
+		; Buffer empty -- load another set
+		mov cx,[FClust]
+		cmp cx,[BufSafe]
+		jna getc_oksize
+		mov cx,[BufSafe]
+getc_oksize:	sub [FClust],cx		; Reduce remaining clusters
+		mov si,[FNextClust]
+		push es			; ES may be != DS, save old ES
+		push ds
+		pop es
+		mov bx,getcbuf
+		push bx
+		call getfssec		; Load a trackbuf full of data
+		mov [FNextClust],si	; Store new next pointer
+		pop si			; SI -> newly loaded data
+		pop es			; Restore ES
+getc_loaded:	lodsb			; Load a byte
+		mov [FPtr],si		; Update next byte pointer
+		dec dword [FBytes]	; Update bytes left counter
+		clc			; Not EOF
+getc_ret:	ret
+
+;
+; ungetc:	Push a character (in AL) back into the getc buffer
+;		Note: if more than one byte is pushed back, this may cause
+;		bytes to be written below the getc buffer boundary.  If there
+;		is a risk for this to occur, the getcbuf base address should
+;		be moved up.
+;
+ungetc:
+		mov si,[FPtr]
+		dec si
+		mov [si],al
+		mov [FPtr],si
+		inc dword [FBytes]
+		ret
+
+;
+; skipspace:	Skip leading whitespace using "getc".  If we hit end-of-line
+;		or end-of-file, return with carry set; ZF = true of EOF
+;		ZF = false for EOLN; otherwise CF = ZF = 0.
+;
+;		Otherwise AL = first character after whitespace
+;
+skipspace:
+skipspace_loop: call getc
+		jc skipspace_eof
+		cmp al,1Ah			; DOS EOF
+		je skipspace_eof
+		cmp al,0Ah
+		je skipspace_eoln
+		cmp al,' '
+		jbe skipspace_loop
+		ret				; CF = ZF = 0
+skipspace_eof:	cmp al,al			; Set ZF
+		stc				; Set CF
+		ret
+skipspace_eoln: add al,0FFh			; Set CF, clear ZF
+		ret
+
+;
+; getint:	Load an integer from the getc file.
+;		Return CF if error; otherwise return integer in EBX
+;
+getint:
+		mov di,NumBuf
+gi_getnum:	cmp di,NumBufEnd	; Last byte in NumBuf
+		jae gi_loaded
+		push di
+		call getc
+		pop di
+		jc gi_loaded
+		stosb
+		cmp al,'-'
+		jnb gi_getnum
+		call ungetc		; Unget non-numeric
+gi_loaded:	mov byte [di],0
+		mov si,NumBuf
+		; Fall through to parseint
+
+;
+; parseint:	Convert an integer to a number in EBX
+;		Get characters from string in DS:SI
+;		Return CF on error
+;		DS:SI points to first character after number
+;
+;               Syntaxes accepted: [-]dec, [-]0+oct, [-]0x+hex, val+K, val+M
+;
+parseint:
+                push eax
+                push ecx
+		push bp
+		xor eax,eax		; Current digit (keep eax == al)
+		mov ebx,eax		; Accumulator
+		mov ecx,ebx		; Base
+                xor bp,bp               ; Used for negative flag
+pi_begin:	lodsb
+		cmp al,'-'
+		jne pi_not_minus
+		xor bp,1		; Set unary minus flag
+		jmp short pi_begin
+pi_not_minus:
+		cmp al,'0'
+		jb pi_err
+		je pi_octhex
+		cmp al,'9'
+		ja pi_err
+		mov cl,10		; Base = decimal
+		jmp short pi_foundbase
+pi_octhex:
+		lodsb
+		cmp al,'0'
+		jb pi_km		; Value is zero
+		or al,20h		; Downcase
+		cmp al,'x'
+		je pi_ishex
+		cmp al,'7'
+		ja pi_err
+		mov cl,8		; Base = octal
+		jmp short pi_foundbase
+pi_ishex:
+		mov al,'0'		; No numeric value accrued yet
+		mov cl,16		; Base = hex
+pi_foundbase:
+                call unhexchar
+                jc pi_km                ; Not a (hex) digit
+                cmp al,cl
+		jae pi_km		; Invalid for base
+		imul ebx,ecx		; Multiply accumulated by base
+                add ebx,eax             ; Add current digit
+		lodsb
+		jmp short pi_foundbase
+pi_km:
+		dec si			; Back up to last non-numeric
+		lodsb
+		or al,20h
+		cmp al,'k'
+		je pi_isk
+		cmp al,'m'
+		je pi_ism
+		dec si			; Back up
+pi_fini:	and bp,bp
+		jz pi_ret		; CF=0!
+		neg ebx			; Value was negative
+pi_done:	clc
+pi_ret:		pop bp
+                pop ecx
+                pop eax
+		ret
+pi_err:		stc
+		jmp short pi_ret
+pi_isk:		shl ebx,10		; x 2^10
+		jmp short pi_done
+pi_ism:		shl ebx,20		; x 2^20
+		jmp short pi_done
+
+;
+; unhexchar:    Convert a hexadecimal digit in AL to the equivalent number;
+;               return CF=1 if not a hex digit
+;
+unhexchar:
+                cmp al,'0'
+		jb uxc_ret		; If failure, CF == 1 already
+                cmp al,'9'
+                ja uxc_1
+		sub al,'0'		; CF <- 0
+		ret
+uxc_1:          or al,20h		; upper case -> lower case
+		cmp al,'a'
+                jb uxc_ret		; If failure, CF == 1 already
+                cmp al,'f'
+                ja uxc_err
+                sub al,'a'-10           ; CF <- 0
+                ret
+uxc_err:        stc
+uxc_ret:	ret
+
+;
+;
+; getline:	Get a command line, converting control characters to spaces
+;               and collapsing streches to one; a space is appended to the
+;               end of the string, unless the line is empty.
+;		The line is terminated by ^J, ^Z or EOF and is written
+;		to ES:DI.  On return, DI points to first char after string.
+;		CF is set if we hit EOF.
+;
+getline:
+		call skipspace
+                mov dl,1                ; Empty line -> empty string.
+                jz gl_eof               ; eof
+                jc gl_eoln              ; eoln
+		call ungetc
+gl_fillloop:	push dx
+		push di
+		call getc
+		pop di
+		pop dx
+		jc gl_ret		; CF set!
+		cmp al,' '
+		jna gl_ctrl
+		xor dx,dx
+gl_store:	stosb
+		jmp short gl_fillloop
+gl_ctrl:	cmp al,10
+		je gl_ret		; CF clear!
+		cmp al,26
+		je gl_eof
+		and dl,dl
+		jnz gl_fillloop		; Ignore multiple spaces
+		mov al,' '		; Ctrl -> space
+		inc dx
+		jmp short gl_store
+gl_eoln:        clc                     ; End of line is not end of file
+                jmp short gl_ret
+gl_eof:         stc
+gl_ret:		pushf			; We want the last char to be space!
+		and dl,dl
+		jnz gl_xret
+		mov al,' '
+		stosb
+gl_xret:	popf
+		ret