xref: /original-bsd/lib/libc/vax/string/strrchr.s (revision 00986467)
1/*
2 * Copyright (c) 1988 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 "@(#)strrchr.s	5.2 (Berkeley) 06/27/88"
20#endif /* LIBC_SCCS and not lint */
21
22#ifdef notdef
23_sccsid:.asciz	"@(#)rindex.s	5.4 (Berkeley) 5/25/88"
24#endif
25
26/*
27 * Find the last occurence of c in the string cp.
28 * Return pointer to match or null pointer.
29 *
30 * char *
31 * rindex(cp, c)
32 *	char *cp, c;
33 */
34#include "DEFS.h"
35
36ENTRY(strrchr, 0)
37	movq	4(ap),r1	# r1 = cp; r2 = c
38	tstl	r2		# check for special case c == '\0'
39	bneq	2f
401:
41	locc	$0,$65535,(r1)	# just find end of string
42	beql	1b		# still looking
43	movl	r1,r0		# found it
44	ret
452:
46	moval	tbl,r3		# r3 = address of table
47	bbss	$0,(r3),5f	# insure not reentering
48	movab	(r3)[r2],r5	# table entry for c
49	incb	(r5)
50	clrl	r4		# last found
513:
52	scanc	$65535,(r1),(r3),$1	# look for c or '\0'
53	beql	3b		# keep looking
54	tstb	(r1)		# if have found '\0'
55	beql	4f		#    we are done
56	movl	r1,r4		# save most recently found
57	incl	r1		# skip over character
58	jbr	3b		# keep looking
594:
60	movl	r4,r0		# return last found (if any)
61	clrb	(r5)		# clean up table
62	clrb	(r3)
63	ret
64
65	.data
66tbl:	.space	256
67	.text
68
69/*
70 * Reentrant, but slower version of rindex
71 */
725:
73	movl	r1,r3
74	clrl	r4		# r4 = pointer to last match
756:
76	locc	$0,$65535,(r3)	# look for '\0'
77	bneq	8f
78	decw	r0		# r0 = 65535
791:
80	locc	r2,r0,(r3)	# look for c
81	bneq	7f
82	movl	r1,r3		# reset pointer and ...
83	jbr	6b		# ... try again
847:
85	movl	r1,r4		# stash pointer ...
86	addl3	$1,r1,r3	# ... skip over match and ...
87	decl	r0		# ... decrement count
88	jbr	6b		# ... try again
898:
90	subl3	r3,r1,r0	# length of short block
91	incl	r0		# +1 for '\0'
929:
93	locc	r2,r0,(r3)	# look for c
94	beql	0f
95	movl	r1,r4		# stash pointer ...
96	addl3	$1,r1,r3	# ... skip over match ...
97	decl	r0		# ... adjust count and ...
98	jbr	9b		# ... try again
990:
100	movl	r4,r0		# return stashed pointer
101	ret
102