1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
/* Copyright (C) 1996-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Richard Henderson (rth@tamu.edu)
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<https://www.gnu.org/licenses/>. */
/* Return the address of a given character within a null-terminated
string, or null if it is not found.
This is generally scheduled for the EV5 (got to look out for my own
interests :-), but with EV4 needs in mind. There *should* be no more
stalls for the EV4 than there are for the EV5.
*/
#include <sysdep.h>
.set noreorder
.set noat
ENTRY(strchr)
#ifdef PROF
ldgp gp, 0(pv)
lda AT, _mcount
jsr AT, (AT), _mcount
.prologue 1
#else
.prologue 0
#endif
zapnot a1, 1, a1 # e0 : zero extend the search character
ldq_u t0, 0(a0) # .. e1 : load first quadword
sll a1, 8, t5 # e0 : replicate the search character
andnot a0, 7, v0 # .. e1 : align our loop pointer
or t5, a1, a1 # e0 :
lda t4, -1 # .. e1 : build garbage mask
sll a1, 16, t5 # e0 :
cmpbge zero, t0, t2 # .. e1 : bits set iff byte == zero
mskqh t4, a0, t4 # e0 :
or t5, a1, a1 # .. e1 :
sll a1, 32, t5 # e0 :
cmpbge zero, t4, t4 # .. e1 : bits set iff byte is garbage
or t5, a1, a1 # e0 :
xor t0, a1, t1 # .. e1 : make bytes == c zero
cmpbge zero, t1, t3 # e0 : bits set iff byte == c
or t2, t3, t0 # e1 : bits set iff char match or zero match
andnot t0, t4, t0 # e0 : clear garbage bits
bne t0, $found # .. e1 (zdb)
$loop: ldq t0, 8(v0) # e0 :
addq v0, 8, v0 # .. e1 :
nop # e0 :
xor t0, a1, t1 # .. e1 (ev5 data stall)
cmpbge zero, t0, t2 # e0 : bits set iff byte == 0
cmpbge zero, t1, t3 # .. e1 : bits set iff byte == c
or t2, t3, t0 # e0 :
beq t0, $loop # .. e1 (zdb)
$found: negq t0, t1 # e0 : clear all but least set bit
and t0, t1, t0 # e1 (stall)
and t0, t3, t1 # e0 : bit set iff byte was the char
beq t1, $retnull # .. e1 (zdb)
and t0, 0xf0, t2 # e0 : binary search for that set bit
and t0, 0xcc, t3 # .. e1 :
and t0, 0xaa, t4 # e0 :
cmovne t2, 4, t2 # .. e1 :
cmovne t3, 2, t3 # e0 :
cmovne t4, 1, t4 # .. e1 :
addq t2, t3, t2 # e0 :
addq v0, t4, v0 # .. e1 :
addq v0, t2, v0 # e0 :
ret # .. e1 :
$retnull:
mov zero, v0 # e0 :
ret # .. e1 :
END(strchr)
weak_alias (strchr, index)
libc_hidden_builtin_def (strchr)
|
