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