1 | /* Copyright (C) 1996-2022 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either |
7 | version 2.1 of the License, or (at your option) any later version. |
8 | |
9 | The GNU C Library is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | Lesser General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library. If not, see |
16 | <https://www.gnu.org/licenses/>. */ |
17 | |
18 | /* Copy no more than COUNT bytes of the null-terminated string from |
19 | SRC to DST. If SRC does not cover all of COUNT, the balance is |
20 | zeroed. */ |
21 | |
22 | #include <sysdep.h> |
23 | |
24 | .set noat |
25 | .set noreorder |
26 | |
27 | .text |
28 | |
29 | ENTRY(strncpy) |
30 | ldgp gp, 0(pv) |
31 | #ifdef PROF |
32 | lda AT, _mcount |
33 | jsr AT, (AT), _mcount |
34 | #endif |
35 | .prologue 1 |
36 | |
37 | mov a0, v0 # set return value now |
38 | beq a2, $zerocount |
39 | jsr t9, __stxncpy # do the work of the copy |
40 | |
41 | bne a2, $multiword # do we have full words left? |
42 | |
43 | .align 3 |
44 | subq t8, 1, t2 # e0 : guess not |
45 | subq t10, 1, t3 # .. e1 : |
46 | or t2, t8, t2 # e0 : clear the bits between the last |
47 | or t3, t10, t3 # .. e1 : written byte and the last byte in |
48 | andnot t3, t2, t3 # e0 : COUNT |
49 | zap t0, t3, t0 # e1 : |
50 | stq_u t0, 0(a0) # e0 : |
51 | ret # .. e1 : |
52 | |
53 | $multiword: |
54 | subq t8, 1, t7 # e0 : clear the final bits in the prev |
55 | or t7, t8, t7 # e1 : word |
56 | zapnot t0, t7, t0 # e0 : |
57 | subq a2, 1, a2 # .. e1 : |
58 | stq_u t0, 0(a0) # e0 : |
59 | addq a0, 8, a0 # .. e1 : |
60 | |
61 | beq a2, 1f # e1 : |
62 | blbc a2, 0f # e1 : |
63 | |
64 | stq_u zero, 0(a0) # e0 : zero one word |
65 | subq a2, 1, a2 # .. e1 : |
66 | addq a0, 8, a0 # e0 : |
67 | beq a2, 1f # .. e1 : |
68 | |
69 | 0: stq_u zero, 0(a0) # e0 : zero two words |
70 | subq a2, 2, a2 # .. e1 : |
71 | stq_u zero, 8(a0) # e0 : |
72 | addq a0, 16, a0 # .. e1 : |
73 | bne a2, 0b # e1 : |
74 | unop |
75 | |
76 | 1: ldq_u t0, 0(a0) # e0 : clear the leading bits in the final |
77 | subq t10, 1, t7 # .. e1 : word |
78 | or t7, t10, t7 # e0 : |
79 | zap t0, t7, t0 # e1 (stall) |
80 | stq_u t0, 0(a0) # e0 : |
81 | |
82 | $zerocount: |
83 | ret # .. e1 : |
84 | |
85 | END(strncpy) |
86 | libc_hidden_builtin_def (strncpy) |
87 | |