mkinitrd-magellan/isolinux/getc.inc

;; $Id: getc.inc,v 1.1 2007-09-01 22:44:04 niro Exp $
;; -----------------------------------------------------------------------
;;   
;;   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
1	niro	532	;; $Id: getc.inc,v 1.1 2007-09-01 22:44:04 niro Exp $
2			;; -----------------------------------------------------------------------
3			;;
4			;; Copyright 1994-2002 H. Peter Anvin - All Rights Reserved
5			;;
6			;; This program is free software; you can redistribute it and/or modify
7			;; it under the terms of the GNU General Public License as published by
8			;; the Free Software Foundation, Inc., 53 Temple Place Ste 330,
9			;; Boston MA 02111-1307, USA; either version 2 of the License, or
10			;; (at your option) any later version; incorporated herein by reference.
11			;;
12			;; -----------------------------------------------------------------------
13
14			;;
15			;; getc.inc
16			;;
17			;; Simple file handling library (open, getc, ungetc)
18			;;
19
20			;
21			; open,getc: Load a file a character at a time for parsing in a manner
22			; similar to the C library getc routine. Only one simultaneous
23			; use is supported. Note: "open" trashes the trackbuf.
24			;
25			; open: Input: mangled filename in DS:DI
26			; Output: ZF set on file not found or zero length
27			;
28			; openfd: Input: file handle in SI
29			; Output: none
30			;
31			; getc: Output: CF set on end of file
32			; Character loaded in AL
33			;
34			open:
35			call searchdir
36			jz openfd.ret
37			openfd:
38			pushf
39			mov [FBytes],ax
40			mov [FBytes+2],dx
41			mov eax,[FBytes]
42			add eax,SECTOR_SIZE-1
43			shr eax,SECTOR_SHIFT
44			mov [FSectors],eax ; Number of sectors
45			mov [FNextClust],si ; Cluster pointer
46			mov ax,[EndOfGetCBuf] ; Pointer at end of buffer ->
47			mov [FPtr],ax ; nothing loaded yet
48			popf ; Restore no ZF
49			.ret: ret
50
51			getc:
52			stc ; If we exit here -> EOF
53			mov ecx,[FBytes]
54			jecxz .ret
55			mov si,[FPtr]
56			cmp si,[EndOfGetCBuf]
57			jb .loaded
58			; Buffer empty -- load another set
59			mov ecx,[FSectors]
60			cmp ecx,trackbufsize >> SECTOR_SHIFT
61			jna .oksize
62			mov ecx,trackbufsize >> SECTOR_SHIFT
63			.oksize: sub [FSectors],ecx ; Reduce remaining clusters
64			mov si,[FNextClust]
65			push es ; ES may be != DS, save old ES
66			push ds
67			pop es
68			mov bx,getcbuf
69			push bx
70			call getfssec ; Load a trackbuf full of data
71			mov [FNextClust],si ; Store new next pointer
72			pop si ; SI -> newly loaded data
73			pop es ; Restore ES
74			.loaded: lodsb ; Load a byte, increment SI
75			mov [FPtr],si ; Update next byte pointer
76			dec dword [FBytes] ; Update bytes left counter
77			clc ; Not EOF
78			.ret: ret
79
80			;
81			; ungetc: Push a character (in AL) back into the getc buffer
82			; Note: if more than one byte is pushed back, this may cause
83			; bytes to be written below the getc buffer boundary. If there
84			; is a risk for this to occur, the getcbuf base address should
85			; be moved up.
86			;
87			ungetc:
88			mov si,[FPtr]
89			dec si
90			mov [si],al
91			mov [FPtr],si
92			inc dword [FBytes]
93			ret
94
95			;
96			; skipspace: Skip leading whitespace using "getc". If we hit end-of-line
97			; or end-of-file, return with carry set; ZF = true of EOF
98			; ZF = false for EOLN; otherwise CF = ZF = 0.
99			;
100			; Otherwise AL = first character after whitespace
101			;
102			skipspace:
103			.loop: call getc
104			jc .eof
105			cmp al,1Ah ; DOS EOF
106			je .eof
107			cmp al,0Ah
108			je .eoln
109			cmp al,' '
110			jbe .loop
111			ret ; CF = ZF = 0
112			.eof: cmp al,al ; Set ZF
113			stc ; Set CF
114			ret
115			.eoln: add al,0FFh ; Set CF, clear ZF
116			ret
117
118			;
119			; getint: Load an integer from the getc file.
120			; Return CF if error; otherwise return integer in EBX
121			;
122			getint:
123			mov di,NumBuf
124			.getnum: cmp di,NumBufEnd ; Last byte in NumBuf
125			jae .loaded
126			push di
127			call getc
128			pop di
129			jc .loaded
130			stosb
131			cmp al,'-'
132			jnb .getnum
133			call ungetc ; Unget non-numeric
134			.loaded: mov byte [di],0
135			mov si,NumBuf
136			; Fall through to parseint
137
138			;
139			; parseint: Convert an integer to a number in EBX
140			; Get characters from string in DS:SI
141			; Return CF on error
142			; DS:SI points to first character after number
143			;
144			; Syntaxes accepted: [-]dec, [-]0+oct, [-]0x+hex, val+K, val+M
145			;
146			parseint:
147			push eax
148			push ecx
149			push bp
150			xor eax,eax ; Current digit (keep eax == al)
151			mov ebx,eax ; Accumulator
152			mov ecx,ebx ; Base
153			xor bp,bp ; Used for negative flag
154			.begin: lodsb
155			cmp al,'-'
156			jne .not_minus
157			xor bp,1 ; Set unary minus flag
158			jmp short .begin
159			.not_minus:
160			cmp al,'0'
161			jb .err
162			je .octhex
163			cmp al,'9'
164			ja .err
165			mov cl,10 ; Base = decimal
166			jmp short .foundbase
167			.octhex:
168			lodsb
169			cmp al,'0'
170			jb .km ; Value is zero
171			or al,20h ; Downcase
172			cmp al,'x'
173			je .ishex
174			cmp al,'7'
175			ja .err
176			mov cl,8 ; Base = octal
177			jmp short .foundbase
178			.ishex:
179			mov al,'0' ; No numeric value accrued yet
180			mov cl,16 ; Base = hex
181			.foundbase:
182			call unhexchar
183			jc .km ; Not a (hex) digit
184			cmp al,cl
185			jae .km ; Invalid for base
186			imul ebx,ecx ; Multiply accumulated by base
187			add ebx,eax ; Add current digit
188			lodsb
189			jmp short .foundbase
190			.km:
191			dec si ; Back up to last non-numeric
192			lodsb
193			or al,20h
194			cmp al,'k'
195			je .isk
196			cmp al,'m'
197			je .ism
198			dec si ; Back up
199			.fini: and bp,bp
200			jz .ret ; CF=0!
201			neg ebx ; Value was negative
202			.done: clc
203			.ret: pop bp
204			pop ecx
205			pop eax
206			ret
207			.err: stc
208			jmp short .ret
209			.isk: shl ebx,10 ; x 2^10
210			jmp short .done
211			.ism: shl ebx,20 ; x 2^20
212			jmp short .done
213
214
215			section .bss
216			alignb 4
217			NumBuf resb 15 ; Buffer to load number
218			NumBufEnd resb 1 ; Last byte in NumBuf
219			FBytes resd 1 ; Number of bytes left in getc file
220			FSectors resd 1 ; Number of sectors in getc file
221			FNextClust resw 1 ; Pointer to next cluster in d:o
222			FPtr resw 1 ; Pointer to next char in buffer
223
224			;
225			; unhexchar: Convert a hexadecimal digit in AL to the equivalent number;
226			; return CF=1 if not a hex digit
227			;
228			section .text
229			unhexchar:
230			cmp al,'0'
231			jb .ret ; If failure, CF == 1 already
232			cmp al,'9'
233			ja .notdigit
234			sub al,'0' ; CF <- 0
235			ret
236			.notdigit: or al,20h ; upper case -> lower case
237			cmp al,'a'
238			jb .ret ; If failure, CF == 1 already
239			cmp al,'f'
240			ja .err
241			sub al,'a'-10 ; CF <- 0
242			ret
243			.err: stc
244			.ret: ret
245
246			;
247			;
248			; getline: Get a command line, converting control characters to spaces
249			; and collapsing streches to one; a space is appended to the
250			; end of the string, unless the line is empty.
251			; The line is terminated by ^J, ^Z or EOF and is written
252			; to ES:DI. On return, DI points to first char after string.
253			; CF is set if we hit EOF.
254			;
255			getline:
256			call skipspace
257			mov dl,1 ; Empty line -> empty string.
258			jz .eof ; eof
259			jc .eoln ; eoln
260			call ungetc
261			.fillloop: push dx
262			push di
263			call getc
264			pop di
265			pop dx
266			jc .ret ; CF set!
267			cmp al,' '
268			jna .ctrl
269			xor dx,dx
270			.store: stosb
271			jmp short .fillloop
272			.ctrl: cmp al,10
273			je .ret ; CF clear!
274			cmp al,26
275			je .eof
276			and dl,dl
277			jnz .fillloop ; Ignore multiple spaces
278			mov al,' ' ; Ctrl -> space
279			inc dx
280			jmp short .store
281			.eoln: clc ; End of line is not end of file
282			jmp short .ret
283			.eof: stc
284			.ret: pushf ; We want the last char to be space!
285			and dl,dl
286			jnz .xret
287			mov al,' '
288			stosb
289			.xret: popf
290			ret