1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * arch/alpha/lib/strncat.S
4 * Contributed by Richard Henderson (rth@tamu.
5 *
6 * Append no more than COUNT characters from t
7 * to the null-terminated string DST. Always
8 *
9 * This differs slightly from the semantics in
10 * past count, whereas libc may write to count
11 * implementation in lib/string.c and is, IMHO
12 */
13 #include <linux/export.h>
14 .text
15
16 .align 3
17 .globl strncat
18 .ent strncat
19 strncat:
20 .frame $30, 0, $26
21 .prologue 0
22
23 mov $16, $0 # set up retur
24 beq $18, $zerocount
25
26 /* Find the end of the string. */
27
28 ldq_u $1, 0($16) # load first q
29 lda $2, -1($31)
30 insqh $2, $16, $2
31 andnot $16, 7, $16
32 or $2, $1, $1
33 cmpbge $31, $1, $2 # bits set iff
34 bne $2, $found
35
36 $loop: ldq $1, 8($16)
37 addq $16, 8, $16
38 cmpbge $31, $1, $2
39 beq $2, $loop
40
41 $found: negq $2, $3 # clear all bu
42 and $2, $3, $2
43
44 and $2, 0xf0, $3 # binary searc
45 and $2, 0xcc, $4
46 and $2, 0xaa, $5
47 cmovne $3, 4, $3
48 cmovne $4, 2, $4
49 cmovne $5, 1, $5
50 addq $3, $4, $3
51 addq $16, $5, $16
52 addq $16, $3, $16
53
54 /* Now do the append. */
55
56 bsr $23, __stxncpy
57
58 /* Worry about the null termination.
59
60 zapnot $1, $27, $2 # was last byt
61 bne $2, 0f
62 ret
63
64 0: cmplt $27, $24, $2 # did we fill
65 or $2, $18, $2
66 bne $2, 2f
67
68 and $24, 0x80, $2 # no zero next
69 bne $2, 1f
70
71 /* Here there are bytes left in the cu
72 addq $24, $24, $24 # end-of-count
73 2: zap $1, $24, $1
74 stq_u $1, 0($16)
75 ret
76
77 1: /* Here we must read the next DST word
78 ldq_u $1, 8($16)
79 zap $1, 1, $1
80 stq_u $1, 8($16)
81
82 $zerocount:
83 ret
84
85 .end strncat
86 EXPORT_SYMBOL(strncat)
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