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- /*
- * Copyright (c) 1988 Regents of the University of California.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
- #if defined(LIBC_SCCS) && !defined(lint)
- .asciz "@(#)strrchr.s 5.4 (Berkeley) 6/1/90"
- #endif /* LIBC_SCCS and not lint */
-
- /*
- * Find the last occurence of c in the string cp.
- * Return pointer to match or null pointer.
- *
- * char *
- * strrchr(cp, c)
- * char *cp, c;
- */
- #include "DEFS.h"
-
- .lcomm tbl,256
-
- ENTRY(strrchr, 0)
- movzwl $65535,r4 /* handy 65535 */
- movq 4(ap),r1 /* r1 = cp; r2 = c */
- movzbl r2,r2
- beql Lzero /* special case for c == '\0' */
-
- clrl r5 /* r5 = pointer to last match */
-
- /*
- * Fancy scanc version. Alas, it is not reentrant.
- */
- movab tbl,r3 /* r3 = address of table */
- bbss $0,(r3),Lreent /* ensure not reentering */
- movab (r3)[r2],r4
- incb (r4) /* mark both '\0' and c */
- 0:
- scanc $65535,(r1),(r3),$1 /* look for c or '\0' */
- beql 0b /* keep looking */
- tstb (r1)
- beql 1f /* done if '\0' */
- movab (r1)+,r5 /* save most recently found, and skip over it */
- jbr 0b /* keep looking */
- 1:
- movl r5,r0 /* return last found (if any) */
- clrb (r4) /* clean up table */
- clrb (r3)
- ret
-
- /*
- * Special case for \0.
- */
- Lzero:
- locc $0,r4,(r1) /* just find end of string */
- beql Lzero /* still looking */
- movl r1,r0 /* found it */
- ret
-
- /*
- * Slower reentrant version is two two-step searches. The first
- * phase runs until we know where the string ends; it locates any
- * occurrences of c within a 65535-byte block. Once we have found
- * the end of the string, we find any further occurrences before
- * that location.
- */
- Lreent:
- 0: /* first phase */
- movl r1,r3
- locc $0,r4,(r3) /* look for '\0' */
- bneq 1f
- locc r2,r4,(r3) /* continue phase 1 search for c */
- beql 0b
- movab (r1)+,r5 /* found c: save and increment pointer */
- brb 0b /* and continue */
-
- 1: /* second phase */
- subl3 r3,r1,r0 /* length of short block */
- movl r3,r1
- 2:
- locc r2,r0,(r1) /* look for c */
- beql 3f /* skip if not found */
- movab (r1)+,r5 /* save pointer as before */
- sobgtr r0,2b /* adjust count and loop */
- 3:
- movl r5,r0 /* return stashed pointer */
- ret
-