xref: /original-bsd/lib/libc/vax/string/rindex.s (revision 28301386)
1/*
2 * Copyright (c) 1983 Regents of the University of California.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms are permitted
6 * provided that the above copyright notice and this paragraph are
7 * duplicated in all such forms and that any documentation,
8 * advertising materials, and other materials related to such
9 * distribution and use acknowledge that the software was developed
10 * by the University of California, Berkeley.  The name of the
11 * University may not be used to endorse or promote products derived
12 * from this software without specific prior written permission.
13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16 */
17
18#if defined(LIBC_SCCS) && !defined(lint)
19	.asciz "@(#)rindex.s	5.5 (Berkeley) 06/27/88"
20#endif /* LIBC_SCCS and not lint */
21
22/*
23 * Find the last occurence of c in the string cp.
24 * Return pointer to match or null pointer.
25 *
26 * char *
27 * rindex(cp, c)
28 *	char *cp, c;
29 */
30#include "DEFS.h"
31
32ENTRY(rindex, 0)
33	movq	4(ap),r1	# r1 = cp; r2 = c
34	tstl	r2		# check for special case c == '\0'
35	bneq	2f
361:
37	locc	$0,$65535,(r1)	# just find end of string
38	beql	1b		# still looking
39	movl	r1,r0		# found it
40	ret
412:
42	moval	tbl,r3		# r3 = address of table
43	bbss	$0,(r3),5f	# insure not reentering
44	movab	(r3)[r2],r5	# table entry for c
45	incb	(r5)
46	clrl	r4		# last found
473:
48	scanc	$65535,(r1),(r3),$1	# look for c or '\0'
49	beql	3b		# keep looking
50	tstb	(r1)		# if have found '\0'
51	beql	4f		#    we are done
52	movl	r1,r4		# save most recently found
53	incl	r1		# skip over character
54	jbr	3b		# keep looking
554:
56	movl	r4,r0		# return last found (if any)
57	clrb	(r5)		# clean up table
58	clrb	(r3)
59	ret
60
61	.data
62tbl:	.space	256
63	.text
64
65/*
66 * Reentrant, but slower version of rindex
67 */
685:
69	movl	r1,r3
70	clrl	r4		# r4 = pointer to last match
716:
72	locc	$0,$65535,(r3)	# look for '\0'
73	bneq	8f
74	decw	r0		# r0 = 65535
751:
76	locc	r2,r0,(r3)	# look for c
77	bneq	7f
78	movl	r1,r3		# reset pointer and ...
79	jbr	6b		# ... try again
807:
81	movl	r1,r4		# stash pointer ...
82	addl3	$1,r1,r3	# ... skip over match and ...
83	decl	r0		# ... decrement count
84	jbr	6b		# ... try again
858:
86	subl3	r3,r1,r0	# length of short block
87	incl	r0		# +1 for '\0'
889:
89	locc	r2,r0,(r3)	# look for c
90	beql	0f
91	movl	r1,r4		# stash pointer ...
92	addl3	$1,r1,r3	# ... skip over match ...
93	decl	r0		# ... adjust count and ...
94	jbr	9b		# ... try again
950:
96	movl	r4,r0		# return stashed pointer
97	ret
98