99 lines
2.9 KiB
ArmAsm
99 lines
2.9 KiB
ArmAsm
/* Copyright (C) 2000-2022 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)
|