Return to strncpy.s CVS log

Up to [CSRG BSD Unix] / 43BSDReno / lib / libc / vax / string

Annotation of 43BSDReno/lib/libc/vax/string/strncpy.s, revision 1.1

1.1     ! root        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 are permitted
        !             6:  * provided that: (1) source distributions retain this entire copyright
        !             7:  * notice and comment, and (2) distributions including binaries display
        !             8:  * the following acknowledgement:  ``This product includes software
        !             9:  * developed by the University of California, Berkeley and its contributors''
        !            10:  * in the documentation or other materials provided with the distribution
        !            11:  * and in all advertising materials mentioning features or use of this
        !            12:  * software. Neither the name of the University nor the names of its
        !            13:  * contributors may be used to endorse or promote products derived
        !            14:  * from this software without specific prior written permission.
        !            15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
        !            16:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
        !            17:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            18:  */
        !            19: 
        !            20: #if defined(LIBC_SCCS) && !defined(lint)
        !            21:        .asciz "@(#)strncpy.s   5.6 (Berkeley) 6/1/90"
        !            22: #endif /* LIBC_SCCS and not lint */
        !            23: 
        !            24: /*
        !            25:  * Copy string s2 over top of string s1.
        !            26:  * Truncate or null-pad to n bytes.
        !            27:  *
        !            28:  * char *
        !            29:  * strncpy(s1, s2, n)
        !            30:  *     char *s1, *s2;
        !            31:  */
        !            32: #include "DEFS.h"
        !            33: 
        !            34: ENTRY(strncpy, R6)
        !            35:        movl    12(ap),r6       # r6 = n
        !            36:        bleq    done            # n <= 0
        !            37:        movl    4(ap),r3        # r3 = s1
        !            38:        movl    8(ap),r1        # r1 = s2
        !            39: 1:
        !            40:        movzwl  $65535,r2       # r2 = bytes in first chunk
        !            41:        cmpl    r6,r2           # r2 = min(bytes in chunk, n);
        !            42:        jgeq    2f
        !            43:        movl    r6,r2
        !            44: 2:
        !            45:        subl2   r2,r6           # update n
        !            46:        locc    $0,r2,(r1)      # '\0' found?
        !            47:        jneq    3f
        !            48:        subl2   r2,r1           # back up pointer updated by locc
        !            49:        movc3   r2,(r1),(r3)    # copy in next piece
        !            50:        tstl    r6              # run out of space?
        !            51:        jneq    1b
        !            52:        jbr     done
        !            53: 3:                             # copy up to '\0' logic
        !            54:        addl2   r0,r6           # r6 = number of null-pad bytes
        !            55:        subl2   r0,r2           # r2 = number of bytes to move
        !            56:        subl2   r2,r1           # back up pointer updated by locc
        !            57:        movc3   r2,(r1),(r3)    # copy in last piece
        !            58: 4:                             # null-pad logic
        !            59:        movzwl  $65535,r2       # r2 = bytes in first chunk
        !            60:        cmpl    r6,r2           # r2 = min(bytes in chunk, n);
        !            61:        jgeq    5f
        !            62:        movl    r6,r2
        !            63: 5:
        !            64:        subl2   r2,r6           # update n
        !            65:        movc5   $0,(r3),$0,r2,(r3)# pad with '\0's
        !            66:        tstl    r6              # finished padding?
        !            67:        jneq    4b
        !            68: done:
        !            69:        movl    4(ap),r0        # return s1
        !            70:        ret

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.