getc.inc - pub/scm/boot/syslinux/syslinux - Git at Google

 ;; $Id$
 ;; -----------------------------------------------------------------------
 ;;
 ;;   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,
 ;;   Boston 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 openfd.ret
 openfd:
 		pushf
 		mov [FBytes],ax
 		mov [FBytes+2],dx
 		mov eax,[FBytes]
 		add eax,SECTOR_SIZE-1
 		shr eax,SECTOR_SHIFT
 		mov [FSectors],eax	; Number of sectors
 		mov [FNextClust],si	; Cluster pointer
 		mov ax,[EndOfGetCBuf]	; Pointer at end of buffer ->
 		mov [FPtr],ax		;  nothing loaded yet
 		popf			; Restore no ZF
 .ret:		ret

 getc:
 		stc			; If we exit here -> EOF
 		mov ecx,[FBytes]
 		jecxz .ret
 		mov si,[FPtr]
 		cmp si,[EndOfGetCBuf]
 		jb .loaded
 		; Buffer empty -- load another set
 		mov ecx,[FSectors]
 		cmp ecx,trackbufsize >> SECTOR_SHIFT
 		jna .oksize
 		mov ecx,trackbufsize >> SECTOR_SHIFT
 .oksize:	sub [FSectors],ecx	; 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
 .loaded:	lodsb			; Load a byte, increment SI
 		mov [FPtr],si		; Update next byte pointer
 		dec dword [FBytes]	; Update bytes left counter
 		clc			; Not EOF
 .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:
 .loop:		call getc
 		jc .eof
 		cmp al,1Ah			; DOS EOF
 		je .eof
 		cmp al,0Ah
 		je .eoln
 		cmp al,' '
 		jbe .loop
 		ret				; CF = ZF = 0
 .eof:		cmp al,al			; Set ZF
 		stc				; Set CF
 		ret
 .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
 .getnum:	cmp di,NumBufEnd	; Last byte in NumBuf
 		jae .loaded
 		push di
 		call getc
 		pop di
 		jc .loaded
 		stosb
 		cmp al,'-'
 		jnb .getnum
 		call ungetc		; Unget non-numeric
 .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
 .begin:		lodsb
 		cmp al,'-'
 		jne .not_minus
 		xor bp,1		; Set unary minus flag
 		jmp short .begin
 .not_minus:
 		cmp al,'0'
 		jb .err
 		je .octhex
 		cmp al,'9'
 		ja .err
 		mov cl,10		; Base = decimal
 		jmp short .foundbase
 .octhex:
 		lodsb
 		cmp al,'0'
 		jb .km		; Value is zero
 		or al,20h		; Downcase
 		cmp al,'x'
 		je .ishex
 		cmp al,'7'
 		ja .err
 		mov cl,8		; Base = octal
 		jmp short .foundbase
 .ishex:
 		mov al,'0'		; No numeric value accrued yet
 		mov cl,16		; Base = hex
 .foundbase:
                 call unhexchar
                 jc .km                ; Not a (hex) digit
                 cmp al,cl
 		jae .km		; Invalid for base
 		imul ebx,ecx		; Multiply accumulated by base
                 add ebx,eax             ; Add current digit
 		lodsb
 		jmp short .foundbase
 .km:
 		dec si			; Back up to last non-numeric
 		lodsb
 		or al,20h
 		cmp al,'k'
 		je .isk
 		cmp al,'m'
 		je .ism
 		dec si			; Back up
 .fini:		and bp,bp
 		jz .ret		; CF=0!
 		neg ebx			; Value was negative
 .done:		clc
 .ret:		pop bp
                 pop ecx
                 pop eax
 		ret
 .err:		stc
 		jmp short .ret
 .isk:		shl ebx,10		; x 2^10
 		jmp short .done
 .ism:		shl ebx,20		; x 2^20
 		jmp short .done


 		section .bss
 		alignb 4
 NumBuf		resb 15			; Buffer to load number
 NumBufEnd	resb 1			; Last byte in NumBuf
 FBytes		resd 1			; Number of bytes left in getc file
 FSectors	resd 1			; Number of sectors in getc file
 FNextClust	resw 1			; Pointer to next cluster in d:o
 FPtr		resw 1			; Pointer to next char in buffer

 ;
 ; unhexchar:    Convert a hexadecimal digit in AL to the equivalent number;
 ;               return CF=1 if not a hex digit
 ;
 		section .text
 unhexchar:
                 cmp al,'0'
 		jb .ret			; If failure, CF == 1 already
                 cmp al,'9'
                 ja .notdigit
 		sub al,'0'		; CF <- 0
 		ret
 .notdigit:	or al,20h		; upper case -> lower case
 		cmp al,'a'
                 jb .ret			; If failure, CF == 1 already
                 cmp al,'f'
                 ja .err
                 sub al,'a'-10           ; CF <- 0
                 ret
 .err:        	stc
 .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 .eof               ; eof
                 jc .eoln              ; eoln
 		call ungetc
 .fillloop:	push dx
 		push di
 		call getc
 		pop di
 		pop dx
 		jc .ret		; CF set!
 		cmp al,' '
 		jna .ctrl
 		xor dx,dx
 .store:		stosb
 		jmp short .fillloop
 .ctrl:		cmp al,10
 		je .ret		; CF clear!
 		cmp al,26
 		je .eof
 		and dl,dl
 		jnz .fillloop		; Ignore multiple spaces
 		mov al,' '		; Ctrl -> space
 		inc dx
 		jmp short .store
 .eoln:		clc                     ; End of line is not end of file
                 jmp short .ret
 .eof:		stc
 .ret:		pushf			; We want the last char to be space!
 		and dl,dl
 		jnz .xret
 		mov al,' '
 		stosb
 .xret:		popf
 		ret
	;; $Id$
	;; -----------------------------------------------------------------------
	;;
	;; 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,
	;; Boston 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 openfd.ret
	openfd:
	pushf
	mov [FBytes],ax
	mov [FBytes+2],dx
	mov eax,[FBytes]
	add eax,SECTOR_SIZE-1
	shr eax,SECTOR_SHIFT
	mov [FSectors],eax ; Number of sectors
	mov [FNextClust],si ; Cluster pointer
	mov ax,[EndOfGetCBuf] ; Pointer at end of buffer ->
	mov [FPtr],ax ; nothing loaded yet
	popf ; Restore no ZF
	.ret: ret

	getc:
	stc ; If we exit here -> EOF
	mov ecx,[FBytes]
	jecxz .ret
	mov si,[FPtr]
	cmp si,[EndOfGetCBuf]
	jb .loaded
	; Buffer empty -- load another set
	mov ecx,[FSectors]
	cmp ecx,trackbufsize >> SECTOR_SHIFT
	jna .oksize
	mov ecx,trackbufsize >> SECTOR_SHIFT
	.oksize: sub [FSectors],ecx ; 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
	.loaded: lodsb ; Load a byte, increment SI
	mov [FPtr],si ; Update next byte pointer
	dec dword [FBytes] ; Update bytes left counter
	clc ; Not EOF
	.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:
	.loop: call getc
	jc .eof
	cmp al,1Ah ; DOS EOF
	je .eof
	cmp al,0Ah
	je .eoln
	cmp al,' '
	jbe .loop
	ret ; CF = ZF = 0
	.eof: cmp al,al ; Set ZF
	stc ; Set CF
	ret
	.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
	.getnum: cmp di,NumBufEnd ; Last byte in NumBuf
	jae .loaded
	push di
	call getc
	pop di
	jc .loaded
	stosb
	cmp al,'-'
	jnb .getnum
	call ungetc ; Unget non-numeric
	.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
	.begin: lodsb
	cmp al,'-'
	jne .not_minus
	xor bp,1 ; Set unary minus flag
	jmp short .begin
	.not_minus:
	cmp al,'0'
	jb .err
	je .octhex
	cmp al,'9'
	ja .err
	mov cl,10 ; Base = decimal
	jmp short .foundbase
	.octhex:
	lodsb
	cmp al,'0'
	jb .km ; Value is zero
	or al,20h ; Downcase
	cmp al,'x'
	je .ishex
	cmp al,'7'
	ja .err
	mov cl,8 ; Base = octal
	jmp short .foundbase
	.ishex:
	mov al,'0' ; No numeric value accrued yet
	mov cl,16 ; Base = hex
	.foundbase:
	call unhexchar
	jc .km ; Not a (hex) digit
	cmp al,cl
	jae .km ; Invalid for base
	imul ebx,ecx ; Multiply accumulated by base
	add ebx,eax ; Add current digit
	lodsb
	jmp short .foundbase
	.km:
	dec si ; Back up to last non-numeric
	lodsb
	or al,20h
	cmp al,'k'
	je .isk
	cmp al,'m'
	je .ism
	dec si ; Back up
	.fini: and bp,bp
	jz .ret ; CF=0!
	neg ebx ; Value was negative
	.done: clc
	.ret: pop bp
	pop ecx
	pop eax
	ret
	.err: stc
	jmp short .ret
	.isk: shl ebx,10 ; x 2^10
	jmp short .done
	.ism: shl ebx,20 ; x 2^20
	jmp short .done


	section .bss
	alignb 4
	NumBuf resb 15 ; Buffer to load number
	NumBufEnd resb 1 ; Last byte in NumBuf
	FBytes resd 1 ; Number of bytes left in getc file
	FSectors resd 1 ; Number of sectors in getc file
	FNextClust resw 1 ; Pointer to next cluster in d:o
	FPtr resw 1 ; Pointer to next char in buffer

	;
	; unhexchar: Convert a hexadecimal digit in AL to the equivalent number;
	; return CF=1 if not a hex digit
	;
	section .text
	unhexchar:
	cmp al,'0'
	jb .ret ; If failure, CF == 1 already
	cmp al,'9'
	ja .notdigit
	sub al,'0' ; CF <- 0
	ret
	.notdigit: or al,20h ; upper case -> lower case
	cmp al,'a'
	jb .ret ; If failure, CF == 1 already
	cmp al,'f'
	ja .err
	sub al,'a'-10 ; CF <- 0
	ret
	.err: stc
	.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 .eof ; eof
	jc .eoln ; eoln
	call ungetc
	.fillloop: push dx
	push di
	call getc
	pop di
	pop dx
	jc .ret ; CF set!
	cmp al,' '
	jna .ctrl
	xor dx,dx
	.store: stosb
	jmp short .fillloop
	.ctrl: cmp al,10
	je .ret ; CF clear!
	cmp al,26
	je .eof
	and dl,dl
	jnz .fillloop ; Ignore multiple spaces
	mov al,' ' ; Ctrl -> space
	inc dx
	jmp short .store
	.eoln: clc ; End of line is not end of file
	jmp short .ret
	.eof: stc
	.ret: pushf ; We want the last char to be space!
	and dl,dl
	jnz .xret
	mov al,' '
	stosb
	.xret: popf
	ret