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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 "@(#)strncat.s 5.6 (Berkeley) 6/1/90"
22: #endif /* LIBC_SCCS and not lint */
23:
24: /*
25: * Concatenate string s2 on the end of s1
26: * and return the base of s1. The parameter
27: * n is the maximum length of string s2 to
28: * concatenate.
29: *
30: * char *
31: * strncat(s1, s2, n)
32: * char *s1, *s2;
33: * int n;
34: */
35: #include "DEFS.h"
36:
37: ENTRY(strncat, R6)
38: movl 12(ap),r6 # r6 = n
39: bleq done # n <= 0
40: movl 4(ap),r3 # r3 = s1
41: movl r3,r1
42: 0:
43: locc $0,$65535,(r1)
44: beql 0b
45: movl r1,r3 # r3 = index(s1, '\0');
46: movl 8(ap),r1 # r1 = s2
47: 1:
48: movzwl $65535,r2 # r2 = bytes in first chunk
49: cmpl r6,r2 # r2 = min(bytes in chunk, n);
50: jgeq 2f
51: movl r6,r2
52: 2:
53: subl2 r2,r6 # update n
54: locc $0,r2,(r1) # '\0' found?
55: jneq 3f
56: subl2 r2,r1 # back up pointer updated by locc
57: movc3 r2,(r1),(r3) # copy in next piece
58: tstl r6 # run out of space?
59: jneq 1b
60: clrb (r3) # force '\0' termination
61: jbr done
62: 3:
63: subl2 r0,r2 # r2 = number of bytes to move
64: subl2 r2,r1 # back up pointer updated by locc
65: incl r2 # copy '\0' as well
66: movc3 r2,(r1),(r3) # copy in last piece
67: done:
68: movl 4(ap),r0 # return s1
69: ret
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