xref: /original-bsd/lib/libc/vax/string/rindex.s (revision 4092c5cc)
1/*
2 * Copyright (c) 1983, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * %sccs.include.redist.c%
6 */
7
8#if defined(LIBC_SCCS) && !defined(lint)
9	.asciz "@(#)rindex.s	8.1 (Berkeley) 06/04/93"
10#endif /* LIBC_SCCS and not lint */
11
12/*
13 * Find the last occurence of c in the string cp.
14 * Return pointer to match or null pointer.
15 *
16 * char *
17 * rindex(cp, c)
18 *	char *cp, c;
19 */
20#include "DEFS.h"
21
22ENTRY(rindex, 0)
23	movq	4(ap),r1	# r1 = cp; r2 = c
24	tstl	r2		# check for special case c == '\0'
25	bneq	2f
261:
27	locc	$0,$65535,(r1)	# just find end of string
28	beql	1b		# still looking
29	movl	r1,r0		# found it
30	ret
312:
32	moval	tbl,r3		# r3 = address of table
33	bbss	$0,(r3),5f	# insure not reentering
34	movab	(r3)[r2],r5	# table entry for c
35	incb	(r5)
36	clrl	r4		# last found
373:
38	scanc	$65535,(r1),(r3),$1	# look for c or '\0'
39	beql	3b		# keep looking
40	tstb	(r1)		# if have found '\0'
41	beql	4f		#    we are done
42	movl	r1,r4		# save most recently found
43	incl	r1		# skip over character
44	jbr	3b		# keep looking
454:
46	movl	r4,r0		# return last found (if any)
47	clrb	(r5)		# clean up table
48	clrb	(r3)
49	ret
50
51	.data
52tbl:	.space	256
53	.text
54
55/*
56 * Reentrant, but slower version of rindex
57 */
585:
59	movl	r1,r3
60	clrl	r4		# r4 = pointer to last match
616:
62	locc	$0,$65535,(r3)	# look for '\0'
63	bneq	8f
64	decw	r0		# r0 = 65535
651:
66	locc	r2,r0,(r3)	# look for c
67	bneq	7f
68	movl	r1,r3		# reset pointer and ...
69	jbr	6b		# ... try again
707:
71	movl	r1,r4		# stash pointer ...
72	addl3	$1,r1,r3	# ... skip over match and ...
73	decl	r0		# ... decrement count
74	jbr	6b		# ... try again
758:
76	subl3	r3,r1,r0	# length of short block
77	incl	r0		# +1 for '\0'
789:
79	locc	r2,r0,(r3)	# look for c
80	beql	0f
81	movl	r1,r4		# stash pointer ...
82	addl3	$1,r1,r3	# ... skip over match ...
83	decl	r0		# ... adjust count and ...
84	jbr	9b		# ... try again
850:
86	movl	r4,r0		# return stashed pointer
87	ret
88