1/* Copyright (C) 2000-2024 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/* Return pointer to first occurrence of CH in STR. */
19
20#include <sysdep.h>
21
22 .arch ev6
23 .set noreorder
24 .set noat
25
26ENTRY(__rawmemchr)
27#ifdef PROF
28 ldgp gp, 0(pv)
29 lda AT, _mcount
30 jsr AT, (AT), _mcount
31 .prologue 1
32#else
33 .prologue 0
34#endif
35
36 ldq_u t0, 0(a0) # L : load first quadword Latency=3
37 and a1, 0xff, t3 # E : 00000000000000ch
38 insbl a1, 1, t5 # U : 000000000000ch00
39 insbl a1, 7, a2 # U : ch00000000000000
40
41 insbl t3, 6, a3 # U : 00ch000000000000
42 or t5, t3, a1 # E : 000000000000chch
43 andnot a0, 7, v0 # E : align our loop pointer
44 lda t4, -1 # E : build garbage mask
45
46 mskqh t4, a0, t4 # U : only want relevant part of first quad
47 or a2, a3, a2 # E : chch000000000000
48 inswl a1, 2, t5 # E : 00000000chch0000
49 inswl a1, 4, a3 # E : 0000chch00000000
50
51 or a1, a2, a1 # E : chch00000000chch
52 or a3, t5, t5 # E : 0000chchchch0000
53 cmpbge zero, t4, t4 # E : bits set iff byte is garbage
54 nop # E :
55
56 /* This quad is _very_ serialized. Lots of stalling happens */
57 or t5, a1, a1 # E : chchchchchchchch
58 xor t0, a1, t1 # E : make bytes == c zero
59 cmpbge zero, t1, t0 # E : bits set iff byte == c
60 andnot t0, t4, t0 # E : clear garbage bits
61
62 cttz t0, a2 # U0 : speculative (in case we get a match)
63 nop # E :
64 nop # E :
65 bne t0, $found # U :
66
67 /*
68 * Yuk. This loop is going to stall like crazy waiting for the
69 * data to be loaded. Not much can be done about it unless it's
70 * unrolled multiple times, which is generally unsafe.
71 */
72$loop:
73 ldq t0, 8(v0) # L : Latency=3
74 addq v0, 8, v0 # E :
75 xor t0, a1, t1 # E :
76 cmpbge zero, t1, t0 # E : bits set iff byte == c
77
78 cttz t0, a2 # U0 : speculative (in case we get a match)
79 nop # E :
80 nop # E :
81 beq t0, $loop # U :
82
83$found:
84 negq t0, t1 # E : clear all but least set bit
85 and t0, t1, t0 # E :
86 addq v0, a2, v0 # E : Add in the bit number from above
87 ret # L0 :
88
89 END(__rawmemchr)
90
91libc_hidden_def (__rawmemchr)
92weak_alias (__rawmemchr, rawmemchr)
93

source code of glibc/sysdeps/alpha/alphaev67/rawmemchr.S