sysdeps/vax/rindex.s

   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, 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.
  20  *
  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.
  32  */
  33
  34 #if defined(LIBC_SCCS) && !defined(lint)
  35         .asciz "@(#)rindex.s    5.6 (Berkeley) 6/1/90"
  36 #endif /* LIBC_SCCS and not lint */
  37
  38 /*
  39  * Find the last occurence of c in the string cp.
  40  * Return pointer to match or null pointer.
  41  *
  42  * char *
  43  * rindex(cp, c)
  44  *      char *cp, c;
  45  */
  46 #include "DEFS.h"
  47
  48 ENTRY(rindex, 0)
  49         movq    4(ap),r1        # r1 = cp; r2 = c
  50         tstl    r2              # check for special case c == '\0'
  51         bneq    2f
  52 1:
  53         locc    $0,$65535,(r1)  # just find end of string
  54         beql    1b              # still looking
  55         movl    r1,r0           # found it
  56         ret
  57 2:
  58         moval   tbl,r3          # r3 = address of table
  59         bbss    $0,(r3),5f      # insure not reentering
  60         movab   (r3)[r2],r5     # table entry for c
  61         incb    (r5)
  62         clrl    r4              # last found
  63 3:
  64         scanc   $65535,(r1),(r3),$1     # look for c or '\0'
  65         beql    3b              # keep looking
  66         tstb    (r1)            # if have found '\0'
  67         beql    4f              #    we are done
  68         movl    r1,r4           # save most recently found
  69         incl    r1              # skip over character
  70         jbr     3b              # keep looking
  71 4:
  72         movl    r4,r0           # return last found (if any)
  73         clrb    (r5)            # clean up table
  74         clrb    (r3)
  75         ret
  76
  77         .data
  78 tbl:    .space  256
  79         .text
  80
  81 /*
  82  * Reentrant, but slower version of rindex
  83  */
  84 5:
  85         movl    r1,r3
  86         clrl    r4              # r4 = pointer to last match
  87 6:
  88         locc    $0,$65535,(r3)  # look for '\0'
  89         bneq    8f
  90         decw    r0              # r0 = 65535
  91 1:
  92         locc    r2,r0,(r3)      # look for c
  93         bneq    7f
  94         movl    r1,r3           # reset pointer and ...
  95         jbr     6b              # ... try again
  96 7:
  97         movl    r1,r4           # stash pointer ...
  98         addl3   $1,r1,r3        # ... skip over match and ...
  99         decl    r0              # ... decrement count
 100         jbr     6b              # ... try again
 101 8:
 102         subl3   r3,r1,r0        # length of short block
 103         incl    r0              # +1 for '\0'
 104 9:
 105         locc    r2,r0,(r3)      # look for c
 106         beql    0f
 107         movl    r1,r4           # stash pointer ...
 108         addl3   $1,r1,r3        # ... skip over match ...
 109         decl    r0              # ... adjust count and ...
 110         jbr     9b              # ... try again
 111 0:
 112         movl    r4,r0           # return stashed pointer
 113         ret