| blob | 5c8dc8622a6205cce4d2c31ffd2d7df79d2037fd |
1 ;; -----------------------------------------------------------------------
2 ;;
3 ;; Copyright 1994-2007 H. Peter Anvin - All Rights Reserved
4 ;;
5 ;; This program is free software; you can redistribute it and/or modify
6 ;; it under the terms of the GNU General Public License as published by
7 ;; the Free Software Foundation, Inc., 53 Temple Place Ste 330,
8 ;; Boston MA 02111-1307, USA; either version 2 of the License, or
9 ;; (at your option) any later version; incorporated herein by reference.
10 ;;
11 ;; -----------------------------------------------------------------------
13 ;;
14 ;; getc.inc
15 ;;
16 ;; Simple file handling library (open, getc, ungetc)
17 ;;
18 ;; WARNING: This interface uses the real_mode_seg/comboot_seg.
19 ;;
21 MAX_GETC_LG2 equ 4 ; Max number of file nesting
22 MAX_GETC equ (1 << MAX_GETC_LG2)
23 bytes_per_getc_lg2 equ 16-MAX_GETC_LG2
24 bytes_per_getc equ (1 << bytes_per_getc_lg2)
25 secs_per_getc equ bytes_per_getc/SECTOR_SIZE
26 MAX_UNGET equ 5 ; Max bytes that can be pushed back
28 struc getc_file
29 gc_file resw 1 ; File pointer
30 gc_bufbytes resw 1 ; Bytes left in buffer
31 gc_bytes resd 1 ; Bytes left in file
32 gc_bufdata resw 1 ; Pointer to data in buffer
33 gc_unget_cnt resb 1 ; Character pushed back count
34 gc_unget_buf resb MAX_UNGET ; Character pushed back buffer
35 endstruc
36 getc_file_lg2 equ 4 ; Size of getc_file as a power of 2
38 %ifndef DEPEND
39 %if (getc_file_size != (1 << getc_file_lg2))
40 %error "getc_file_size != (1 << getc_file_lg2)"
41 %endif
42 %endif
44 ;
45 ; open,getc: Load a file a character at a time for parsing in a manner
46 ; similar to the C library getc routine.
47 ; Up to MAX_GETC files can be open at the same time,
48 ; they are accessed in a stack-like fashion.
49 ;
50 ; All routines assume CS == DS.
51 ;
52 ; open: Input: mangled filename in DS:DI
53 ; Output: ZF set on file not found or zero length
54 ;
55 ; openfd: Input: file handle in SI
56 ; Output: ZF set on getc stack overflow
57 ;
58 ; getc: Output: CF set on end of file
59 ; Character loaded in AL
60 ;
61 ; close: Output: CF set if nothing open
62 ;
63 open:
64 call searchdir
65 jz openfd.ret
66 openfd:
67 push bx
69 mov bx,[CurrentGetC]
70 sub bx,getc_file_size
71 cmp bx,GetCStack
72 jb .stack_full ; Excessive nesting
73 mov [CurrentGetC],bx
75 mov [bx+gc_file],si ; File pointer
76 mov [bx+gc_bytes],ax ; Bytes available
77 mov [bx+gc_bytes+2],dx
78 xor ax,ax
79 mov [bx+gc_bufbytes],ax ; Buffer empty
80 mov [bx+gc_unget_cnt],al ; ungetc buffer empty
82 inc ax ; ZF <- 0
83 pop bx
84 .ret: ret
86 .stack_full:
87 call close_file
88 xor ax,ax ; ZF <- 1
89 pop bx
90 ret
92 getc:
93 push bx
94 push si
95 push di
96 push es
98 mov di,[CurrentGetC]
99 movzx bx,byte [di+gc_unget_cnt]
100 and bx,bx
101 jnz .have_unget
103 mov ax,real_mode_seg ; Borrow the real_mode_seg
104 mov es,ax
105 .got_data:
106 sub word [di+gc_bufbytes],1
107 jc .get_data ; Was it zero already?
108 mov si,[di+gc_bufdata]
109 mov al,[es:si]
110 inc si
111 mov [di+gc_bufdata],si
112 .done:
113 clc
114 .ret:
115 pop es
116 pop di
117 pop si
118 pop bx
119 ret
120 .have_unget:
121 dec bx
122 mov al,[di+bx+gc_unget_buf]
123 mov [di+gc_unget_cnt],bl
124 jmp .done
126 .get_data:
127 pushad
128 ; Compute start of buffer
129 mov bx,di
130 sub bx,GetCStack
131 shl bx,bytes_per_getc_lg2-getc_file_lg2
133 mov [di+gc_bufdata],bx
134 mov si,[di+gc_file]
135 mov ecx,[di+gc_bytes]
136 jecxz .empty
137 cmp ecx,bytes_per_getc
138 jna .sizeok
139 mov ecx,bytes_per_getc
140 .sizeok:
141 mov [di+gc_bufbytes],cx
142 sub [di+gc_bytes],ecx
143 add cx,SECTOR_SIZE-1
144 shr cx,SECTOR_SHIFT
145 call getfssec
146 mov [di+gc_file],si
147 popad
148 jmp .got_data
150 .empty:
151 ; CX == 0 at this point; gc_bufbytes was clobbered
152 ; by the subtract; we need to restore it to zero so
153 ; we will continue to get EOF on any further attempts
154 ; to read the file.
155 mov [di+gc_bufbytes],cx
156 popad
157 stc
158 jmp .ret
160 close:
161 push bx
162 push si
163 mov bx,[CurrentGetC]
164 mov si,[bx+gc_file]
165 call close_file
166 add bx,getc_file_size
167 mov [CurrentGetC],bx
168 pop si
169 pop bx
170 ret
172 ;
173 ; ungetc: Push a character (in AL) back into the getc buffer
174 ; Note: if more than MAX_UNGET bytes are pushed back, all
175 ; hell will break loose.
176 ;
177 ungetc:
178 push di
179 push bx
180 mov di,[CurrentGetC]
181 movzx bx,[di+gc_unget_cnt]
182 mov [bx+di+gc_unget_buf],al
183 inc bx
184 mov [di+gc_unget_cnt],bl
185 pop bx
186 pop di
187 ret
189 ;
190 ; skipspace: Skip leading whitespace using "getc". If we hit end-of-line
191 ; or end-of-file, return with carry set; ZF = true of EOF
192 ; ZF = false for EOLN; otherwise CF = ZF = 0.
193 ;
194 ; Otherwise AL = first character after whitespace
195 ;
196 skipspace:
197 .loop: call getc
198 jc .eof
199 cmp al,1Ah ; DOS EOF
200 je .eof
201 cmp al,0Ah
202 je .eoln
203 cmp al,' '
204 jbe .loop
205 ret ; CF = ZF = 0
206 .eof: cmp al,al ; Set ZF
207 stc ; Set CF
208 ret
209 .eoln: add al,0FFh ; Set CF, clear ZF
210 ret
212 ;
213 ; getint: Load an integer from the getc file.
214 ; Return CF if error; otherwise return integer in EBX
215 ;
216 getint:
217 mov di,NumBuf
218 .getnum: cmp di,NumBufEnd ; Last byte in NumBuf
219 jae .loaded
220 push di
221 call getc
222 pop di
223 jc .loaded
224 stosb
225 cmp al,'-'
226 jnb .getnum
227 call ungetc ; Unget non-numeric
228 .loaded: mov byte [di],0
229 mov si,NumBuf
230 ; Fall through to parseint
232 ;
233 ; parseint: Convert an integer to a number in EBX
234 ; Get characters from string in DS:SI
235 ; Return CF on error
236 ; DS:SI points to first character after number
237 ;
238 ; Syntaxes accepted: [-]dec, [-]0+oct, [-]0x+hex, val+[KMG]
239 ;
240 parseint:
241 push eax
242 push ecx
243 push bp
244 xor eax,eax ; Current digit (keep eax == al)
245 mov ebx,eax ; Accumulator
246 mov ecx,ebx ; Base
247 xor bp,bp ; Used for negative flag
248 .begin: lodsb
249 cmp al,'-'
250 jne .not_minus
251 xor bp,1 ; Set unary minus flag
252 jmp short .begin
253 .not_minus:
254 cmp al,'0'
255 jb .err
256 je .octhex
257 cmp al,'9'
258 ja .err
259 mov cl,10 ; Base = decimal
260 jmp short .foundbase
261 .octhex:
262 lodsb
263 cmp al,'0'
264 jb .km ; Value is zero
265 or al,20h ; Downcase
266 cmp al,'x'
267 je .ishex
268 cmp al,'7'
269 ja .err
270 mov cl,8 ; Base = octal
271 jmp short .foundbase
272 .ishex:
273 mov al,'0' ; No numeric value accrued yet
274 mov cl,16 ; Base = hex
275 .foundbase:
276 call unhexchar
277 jc .km ; Not a (hex) digit
278 cmp al,cl
279 jae .km ; Invalid for base
280 imul ebx,ecx ; Multiply accumulated by base
281 add ebx,eax ; Add current digit
282 lodsb
283 jmp short .foundbase
284 .km:
285 dec si ; Back up to last non-numeric
286 lodsb
287 or al,20h
288 cmp al,'k'
289 je .isk
290 cmp al,'m'
291 je .ism
292 cmp al,'g'
293 je .isg
294 dec si ; Back up
295 .fini: and bp,bp
296 jz .ret ; CF=0!
297 neg ebx ; Value was negative
298 .done: clc
299 .ret: pop bp
300 pop ecx
301 pop eax
302 ret
303 .err: stc
304 jmp short .ret
305 .isg: shl ebx,10 ; * 2^30
306 .ism: shl ebx,10 ; * 2^20
307 .isk: shl ebx,10 ; * 2^10
308 jmp .fini
310 section .bss
311 alignb 4
312 NumBuf resb 15 ; Buffer to load number
313 NumBufEnd resb 1 ; Last byte in NumBuf
315 GetCStack resb getc_file_size*MAX_GETC
316 .end equ $
318 section .data
319 CurrentGetC dw GetCStack.end ; GetCStack empty
321 ;
322 ; unhexchar: Convert a hexadecimal digit in AL to the equivalent number;
323 ; return CF=1 if not a hex digit
324 ;
325 section .text
326 unhexchar:
327 cmp al,'0'
328 jb .ret ; If failure, CF == 1 already
329 cmp al,'9'
330 ja .notdigit
331 sub al,'0' ; CF <- 0
332 ret
333 .notdigit: or al,20h ; upper case -> lower case
334 cmp al,'a'
335 jb .ret ; If failure, CF == 1 already
336 cmp al,'f'
337 ja .err
338 sub al,'a'-10 ; CF <- 0
339 ret
340 .err: stc
341 .ret: ret
343 ;
344 ;
345 ; getline: Get a command line, converting control characters to spaces
346 ; and collapsing streches to one; a space is appended to the
347 ; end of the string, unless the line is empty.
348 ; The line is terminated by ^J, ^Z or EOF and is written
349 ; to ES:DI. On return, DI points to first char after string.
350 ; CF is set if we hit EOF.
351 ;
352 getline:
353 call skipspace
354 mov dl,1 ; Empty line -> empty string.
355 jz .eof ; eof
356 jc .eoln ; eoln
357 call ungetc
358 .fillloop: push dx
359 push di
360 call getc
361 pop di
362 pop dx
363 jc .ret ; CF set!
364 cmp al,' '
365 jna .ctrl
366 xor dx,dx
367 .store: stosb
368 jmp short .fillloop
369 .ctrl: cmp al,10
370 je .ret ; CF clear!
371 cmp al,26
372 je .eof
373 and dl,dl
374 jnz .fillloop ; Ignore multiple spaces
375 mov al,' ' ; Ctrl -> space
376 inc dx
377 jmp short .store
378 .eoln: clc ; End of line is not end of file
379 jmp short .ret
380 .eof: stc
381 .ret: pushf ; We want the last char to be space!
382 and dl,dl
383 jnz .xret
384 mov al,' '
385 stosb
386 .xret: popf
387 ret