1/* Copyright (C) 2000-2022 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/* Return the address of a given character within a null-terminated
19   string, or null if it is not found.  */
20
21#include <sysdep.h>
22
23	.arch ev6
24	.set noreorder
25	.set noat
26
27ENTRY(strchr)
28#ifdef PROF
29	ldgp	gp, 0(pv)
30	lda	AT, _mcount
31	jsr	AT, (AT), _mcount
32	.prologue 1
33#else
34	.prologue 0
35#endif
36
37	ldq_u   t0, 0(a0)	# L : load first quadword Latency=3
38	and	a1, 0xff, t3	# E : 00000000000000ch
39	insbl	a1, 1, t5	# U : 000000000000ch00
40	insbl	a1, 7, a2	# U : ch00000000000000
41
42	insbl	t3, 6, a3	# U : 00ch000000000000
43	or	t5, t3, a1	# E : 000000000000chch
44	andnot  a0, 7, v0	# E : align our loop pointer
45	lda	t4, -1		# E : build garbage mask
46
47	mskqh	t4, a0, t4	# U : only want relevant part of first quad
48	or	a2, a3, a2	# E : chch000000000000
49	inswl	a1, 2, t5	# E : 00000000chch0000
50	inswl	a1, 4, a3	# E : 0000chch00000000
51
52	or	a1, a2, a1	# E : chch00000000chch
53	or	a3, t5, t5	# E : 0000chchchch0000
54	cmpbge  zero, t0, t2	# E : bits set iff byte == zero
55	cmpbge	zero, t4, t4	# E : bits set iff byte is garbage
56
57	/* This quad is _very_ serialized.  Lots of stalling happens */
58	or	t5, a1, a1	# E : chchchchchchchch
59	xor	t0, a1, t1	# E : make bytes == c zero
60	cmpbge  zero, t1, t3	# E : bits set iff byte == c
61	or	t2, t3, t0	# E : bits set iff char match or zero match
62
63	andnot	t0, t4, t0	# E : clear garbage bits
64	cttz	t0, a2		# U0 : speculative (in case we get a match)
65	nop			# E :
66	bne	t0, $found	# U :
67
68	/*
69	 * Yuk.  This loop is going to stall like crazy waiting for the
70	 * data to be loaded.  Not much can be done about it unless it's
71	 * unrolled multiple times, which is generally unsafe.
72	 */
73$loop:
74	ldq	t0, 8(v0)	# L : Latency=3
75	addq	v0, 8, v0	# E :
76	xor	t0, a1, t1	# E :
77	cmpbge	zero, t0, t2	# E : bits set iff byte == 0
78
79	cmpbge	zero, t1, t3	# E : bits set iff byte == c
80	or	t2, t3, t0	# E :
81	cttz	t3, a2		# U0 : speculative (in case we get a match)
82	beq	t0, $loop	# U :
83
84$found:
85	negq    t0, t1		# E : clear all but least set bit
86	and     t0, t1, t0	# E :
87	and	t0, t3, t1	# E : bit set iff byte was the char
88	addq	v0, a2, v0	# E : Add in the bit number from above
89
90	cmoveq	t1, $31, v0	# E : Two mapping slots, latency = 2
91	nop
92	nop
93	ret			# L0 :
94
95	END(strchr)
96
97weak_alias (strchr, index)
98libc_hidden_builtin_def (strchr)
99