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d614a753 | 1 | /* Copyright (C) 1996-2020 Free Software Foundation, Inc. |
3c7b2587 UD |
2 | This file is part of the GNU C Library. |
3 | Contributed by Richard Henderson <rth@tamu.edu>, 1996. | |
cf182b58 | 4 | |
3c7b2587 | 5 | The GNU C Library is free software; you can redistribute it and/or |
3214b89b AJ |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
cf182b58 | 9 | |
3c7b2587 UD |
10 | The GNU C Library is distributed in the hope that it will be useful, |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
3214b89b | 13 | Lesser General Public License for more details. |
cf182b58 | 14 | |
3214b89b | 15 | You should have received a copy of the GNU Lesser General Public |
ab84e3ff | 16 | License along with the GNU C Library. If not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
cf182b58 UD |
18 | |
19 | /* Append no more than COUNT characters from the null-terminated string SRC | |
20 | to the null-terminated string DST. Always null-terminate the new DST. */ | |
21 | ||
22 | #include <sysdep.h> | |
23 | ||
24 | .text | |
25 | ||
26 | ENTRY(strncat) | |
27 | ldgp gp, 0(pv) | |
60c74cf0 | 28 | #ifdef PROF |
3c7b2587 | 29 | .set noat |
60c74cf0 UD |
30 | lda AT, _mcount |
31 | jsr AT, (AT), _mcount | |
3c7b2587 | 32 | .set at |
60c74cf0 | 33 | #endif |
cf182b58 UD |
34 | .prologue 1 |
35 | ||
36 | mov a0, v0 # set up return value | |
37 | beq a2, $zerocount | |
38 | ||
39 | /* Find the end of the string. */ | |
40 | ||
41 | ldq_u t0, 0(a0) # load first quadword (a0 may be misaligned) | |
42 | lda t1, -1(zero) | |
43 | insqh t1, a0, t1 | |
44 | andnot a0, 7, a0 | |
45 | or t1, t0, t0 | |
46 | cmpbge zero, t0, t1 # t1 <- bitmask: bit i == 1 <==> i-th byte == 0 | |
47 | bne t1, $found | |
48 | ||
49 | $loop: ldq t0, 8(a0) | |
50 | addq a0, 8, a0 # addr += 8 | |
51 | cmpbge zero, t0, t1 | |
52 | beq t1, $loop | |
53 | ||
54 | $found: negq t1, t2 # clear all but least set bit | |
55 | and t1, t2, t1 | |
56 | ||
57 | and t1, 0xf0, t2 # binary search for that set bit | |
58 | and t1, 0xcc, t3 | |
59 | and t1, 0xaa, t4 | |
60 | cmovne t2, 4, t2 | |
61 | cmovne t3, 2, t3 | |
62 | cmovne t4, 1, t4 | |
63 | addq t2, t3, t2 | |
64 | addq a0, t4, a0 | |
65 | addq a0, t2, a0 | |
66 | ||
67 | /* Now do the append. */ | |
68 | ||
69 | jsr t9, __stxncpy | |
70 | ||
71 | /* Worry about the null termination. */ | |
72 | ||
73 | zapnot t0, t8, t1 # was last byte a null? | |
74 | bne t1, 0f | |
75 | ret | |
76 | ||
77 | 0: and t10, 0x80, t1 | |
78 | bne t1, 1f | |
79 | ||
80 | /* Here there are bytes left in the current word. Clear one. */ | |
81 | addq t10, t10, t10 # end-of-count bit <<= 1 | |
82 | zap t0, t10, t0 | |
83 | stq_u t0, 0(a0) | |
84 | ret | |
85 | ||
86 | 1: /* Here we must read the next DST word and clear the first byte. */ | |
87 | ldq_u t0, 8(a0) | |
88 | zap t0, 1, t0 | |
89 | stq_u t0, 8(a0) | |
90 | ||
91 | $zerocount: | |
92 | ret | |
93 | ||
94 | END(strncat) |