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/* Copyright (C) 2000-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
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. */
#include <sysdep.h>
.arch ev6
.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
ldq_u t0, 0(a0) # L : load first quadword Latency=3
and a1, 0xff, t3 # E : 00000000000000ch
insbl a1, 1, t5 # U : 000000000000ch00
insbl a1, 7, a2 # U : ch00000000000000
insbl t3, 6, a3 # U : 00ch000000000000
or t5, t3, a1 # E : 000000000000chch
andnot a0, 7, v0 # E : align our loop pointer
lda t4, -1 # E : build garbage mask
mskqh t4, a0, t4 # U : only want relevant part of first quad
or a2, a3, a2 # E : chch000000000000
inswl a1, 2, t5 # E : 00000000chch0000
inswl a1, 4, a3 # E : 0000chch00000000
or a1, a2, a1 # E : chch00000000chch
or a3, t5, t5 # E : 0000chchchch0000
cmpbge zero, t0, t2 # E : bits set iff byte == zero
cmpbge zero, t4, t4 # E : bits set iff byte is garbage
/* This quad is _very_ serialized. Lots of stalling happens */
or t5, a1, a1 # E : chchchchchchchch
xor t0, a1, t1 # E : make bytes == c zero
cmpbge zero, t1, t3 # E : bits set iff byte == c
or t2, t3, t0 # E : bits set iff char match or zero match
andnot t0, t4, t0 # E : clear garbage bits
cttz t0, a2 # U0 : speculative (in case we get a match)
nop # E :
bne t0, $found # U :
/*
* Yuk. This loop is going to stall like crazy waiting for the
* data to be loaded. Not much can be done about it unless it's
* unrolled multiple times, which is generally unsafe.
*/
$loop:
ldq t0, 8(v0) # L : Latency=3
addq v0, 8, v0 # E :
xor t0, a1, t1 # E :
cmpbge zero, t0, t2 # E : bits set iff byte == 0
cmpbge zero, t1, t3 # E : bits set iff byte == c
or t2, t3, t0 # E :
cttz t3, a2 # U0 : speculative (in case we get a match)
beq t0, $loop # U :
$found:
negq t0, t1 # E : clear all but least set bit
and t0, t1, t0 # E :
and t0, t3, t1 # E : bit set iff byte was the char
addq v0, a2, v0 # E : Add in the bit number from above
cmoveq t1, $31, v0 # E : Two mapping slots, latency = 2
nop
nop
ret # L0 :
END(strchr)
weak_alias (strchr, index)
libc_hidden_builtin_def (strchr)
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