Update.
[glibc.git] / sysdeps / vax / strchr.s
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1 /*
2 * Copyright (c) 1988 Regents of the University of California.
3 * All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
34 #if defined(LIBC_SCCS) && !defined(lint)
35 .asciz "@(#)strchr.s 5.4 (Berkeley) 6/1/90"
36 #endif /* LIBC_SCCS and not lint */
39 * Find the first occurrence of c in the string cp.
40 * Return pointer to match or null pointer.
42 * char *
43 * strchr(cp, c)
44 * char *cp, c;
46 #include "DEFS.h"
48 .lcomm tbl,256
50 ENTRY(strchr, 0)
51 movzwl $65535,r4 /* handy constant */
52 movq 4(ap),r1 /* r1 = cp; r2 = c */
53 movzbl r2,r2
54 beql Lzero /* special case for c == '\0' */
57 * Fancy scanc version. Alas, it is not reentrant.
59 movab tbl,r3 /* r3 = base of table */
60 bbss $0,(r3),Lreent /* ensure not reentering */
61 movab (r3)[r2],r5
62 incb (r5) /* mark both '\0' and c */
64 scanc r4,(r1),(r3),$1 /* look for c or '\0' */
65 beql 0b /* still looking */
66 movl r1,r0 /* return whatever we found */
67 tstb (r0)
68 bneq 1f # unless it was '\0':
69 clrl r0 # then return NULL
71 clrb (r5) /* clean up table */
72 clrb (r3)
73 ret
76 * Special case for \0.
78 Lzero:
79 locc r2,r4,(r1) /* just find end of string */
80 beql Lzero /* still looking */
81 movl r1,r0 /* found it */
82 ret
85 * Slower reentrant version is two two-step searches. The first
86 * phase runs until we know where the string ends; it locates the
87 * first occurrence of c within a 65535-byte block. If we find
88 * the end of the string first, we switch to the second phase,
89 * were we look only up to the known end of string.
91 Lreent:
92 0: /* first phase */
93 movl r1,r3
94 locc $0,r4,(r3) /* look for '\0' */
95 bneq 1f
96 locc r2,r4,(r3) /* look for c */
97 beql 0b /* not found: reset pointer and loop */
98 movl r1,r0 /* found: return it */
99 ret
100 1: /* second phase */
101 subl3 r3,r1,r0 /* length of short block */
102 locc r2,r0,(r3) /* look for c */
103 beql 2f /* not found: return NULL */
104 movl r1,r0
105 2: ret
107 weak_alias (strchr, index)