glibc/sysdeps/alpha/strchr.S
Siddhesh Poyarekar 30891f35fa Remove "Contributed by" lines
We stopped adding "Contributed by" or similar lines in sources in 2012
in favour of git logs and keeping the Contributors section of the
glibc manual up to date.  Removing these lines makes the license
header a bit more consistent across files and also removes the
possibility of error in attribution when license blocks or files are
copied across since the contributed-by lines don't actually reflect
reality in those cases.

Move all "Contributed by" and similar lines (Written by, Test by,
etc.) into a new file CONTRIBUTED-BY to retain record of these
contributions.  These contributors are also mentioned in
manual/contrib.texi, so we just maintain this additional record as a
courtesy to the earlier developers.

The following scripts were used to filter a list of files to edit in
place and to clean up the CONTRIBUTED-BY file respectively.  These
were not added to the glibc sources because they're not expected to be
of any use in future given that this is a one time task:

https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc
https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-09-03 22:06:44 +05:30

94 lines
2.9 KiB
ArmAsm

/* Copyright (C) 1996-2021 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.
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)