1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * arch/alpha/lib/strncpy.S
4 * Contributed by Richard Henderson (rth@tamu.
5 *
6 * Copy no more than COUNT bytes of the null-t
7 * SRC to DST. If SRC does not cover all of C
8 * zeroed.
9 *
10 * Or, rather, if the kernel cared about that
11 * version has cropped that bit o' nastiness a
12 * __stxncpy is in range of a branch.
13 */
14 #include <linux/export.h>
15 .set noat
16 .set noreorder
17
18 .text
19
20 .align 4
21 .globl strncpy
22 .ent strncpy
23 strncpy:
24 .frame $30, 0, $26
25 .prologue 0
26
27 mov $16, $0 # set return v
28 beq $18, $zerolen
29 unop
30 bsr $23, __stxncpy # do the work
31
32 unop
33 bne $18, $multiword # do we have f
34 subq $24, 1, $3 # nope
35 subq $27, 1, $4
36
37 or $3, $24, $3 # clear the bi
38 or $4, $27, $4 # written byte
39 andnot $3, $4, $4
40 zap $1, $4, $1
41
42 stq_u $1, 0($16)
43 ret
44
45 .align 4
46 $multiword:
47 subq $27, 1, $2 # clear the fi
48 or $2, $27, $2
49 zapnot $1, $2, $1
50 subq $18, 1, $18
51
52 stq_u $1, 0($16)
53 addq $16, 8, $16
54 unop
55 beq $18, 1f
56
57 nop
58 unop
59 nop
60 blbc $18, 0f
61
62 stq_u $31, 0($16) # zero one wor
63 subq $18, 1, $18
64 addq $16, 8, $16
65 beq $18, 1f
66
67 0: stq_u $31, 0($16) # zero two wor
68 subq $18, 2, $18
69 stq_u $31, 8($16)
70 addq $16, 16, $16
71 bne $18, 0b
72
73 1: ldq_u $1, 0($16) # clear the le
74 subq $24, 1, $2
75 or $2, $24, $2
76
77 zap $1, $2, $1
78 stq_u $1, 0($16)
79 $zerolen:
80 ret
81
82 .end strncpy
83 EXPORT_SYMBOL(strncpy)
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