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Annotation of 43BSD/lib/libc/vax/gen/rindex.s, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1983 Regents of the University of California.
                      3:  * All rights reserved.  The Berkeley software License Agreement
                      4:  * specifies the terms and conditions for redistribution.
                      5:  */
                      6: 
                      7: #ifdef LIBC_SCCS
                      8:        .asciz  "@(#)rindex.s   5.3 (Berkeley) 3/9/86"
                      9: #endif LIBC_SCCS
                     10: 
                     11: /*
                     12:  * Find the last occurence of c in the string cp.
                     13:  * Return pointer to match or null pointer.
                     14:  *
                     15:  * char *
                     16:  * rindex(cp, c)
                     17:  *     char *cp, c;
                     18:  */
                     19: #include "DEFS.h"
                     20: 
                     21: ENTRY(rindex, 0)
                     22:        movq    4(ap),r1        # r1 = cp; r2 = c
                     23:        tstl    r2              # check for special case c == '\0'
                     24:        bneq    2f
                     25: 1:
                     26:        locc    $0,$65535,(r1)  # just find end of string
                     27:        beql    1b              # still looking
                     28:        movl    r1,r0           # found it
                     29:        ret
                     30: 2:
                     31:        moval   tbl,r3          # r3 = address of table
                     32:        bbss    $0,(r3),5f      # insure not reentering
                     33:        movab   (r3)[r2],r5     # table entry for c
                     34:        incb    (r5)
                     35:        clrl    r4              # last found
                     36: 3:
                     37:        scanc   $65535,(r1),(r3),$1     # look for c or '\0'
                     38:        beql    3b              # keep looking
                     39:        tstb    (r1)            # if have found '\0'
                     40:        beql    4f              #    we are done
                     41:        movl    r1,r4           # save most recently found
                     42:        incl    r1              # skip over character
                     43:        jbr     3b              # keep looking
                     44: 4:
                     45:        movl    r4,r0           # return last found (if any)
                     46:        clrb    (r5)            # clean up table
                     47:        clrb    (r3)
                     48:        ret
                     49: 
                     50:        .data
                     51: tbl:   .space  256
                     52:        .text
                     53: 
                     54: /*
                     55:  * Reentrant, but slower version of rindex
                     56:  */
                     57: 5:
                     58:        movl    r1,r3
                     59:        clrl    r4              # r4 = pointer to last match
                     60: 6:
                     61:        locc    $0,$65535,(r3)  # look for '\0'
                     62:        bneq    8f
                     63:        decw    r0              # r0 = 65535
                     64: 1:
                     65:        locc    r2,r0,(r3)      # look for c
                     66:        bneq    7f
                     67:        movl    r1,r3           # reset pointer and ...
                     68:        jbr     6b              # ... try again
                     69: 7:
                     70:        movl    r1,r4           # stash pointer ...
                     71:        addl3   $1,r1,r3        # ... skip over match and ...
                     72:        decl    r0              # ... decrement count
                     73:        jbr     6b              # ... try again
                     74: 8:
                     75:        subl3   r3,r1,r0        # length of short block
                     76:        incl    r0              # +1 for '\0'
                     77: 9:
                     78:        locc    r2,r0,(r3)      # look for c
                     79:        beql    0f
                     80:        movl    r1,r4           # stash pointer ...
                     81:        addl3   $1,r1,r3        # ... skip over match ...
                     82:        decl    r0              # ... adjust count and ...
                     83:        jbr     9b              # ... try again
                     84: 0:
                     85:        movl    r4,r0           # return stashed pointer
                     86:        ret

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