mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-15 01:21:06 +00:00
111 lines
3.1 KiB
ArmAsm
111 lines
3.1 KiB
ArmAsm
/* Optimized version of the standard strchr() function.
|
|
This file is part of the GNU C Library.
|
|
Copyright (C) 2000-2023 Free Software Foundation, Inc.
|
|
|
|
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 the first occurrence of chr in str or NULL
|
|
|
|
Inputs:
|
|
in0: str
|
|
in1: chr
|
|
|
|
A modified version of memchr.S, the search ends when the character is
|
|
found or the terminating null character is encountered.
|
|
|
|
This implementation assumes little endian mode. For big endian mode,
|
|
the instruction czx1.r should be replaced by czx1.l. */
|
|
|
|
#include <sysdep.h>
|
|
#undef ret
|
|
|
|
#define saved_lc r18
|
|
#define poschr r19
|
|
#define pos0 r20
|
|
#define val1 r21
|
|
#define val2 r22
|
|
#define tmp r24
|
|
#define chrx8 r25
|
|
#define loopcnt r30
|
|
|
|
#define str in0
|
|
#define chr in1
|
|
|
|
ENTRY(strchr)
|
|
.prologue
|
|
alloc r2 = ar.pfs, 2, 0, 0, 0
|
|
.save ar.lc, saved_lc
|
|
mov saved_lc = ar.lc // save the loop counter
|
|
.body
|
|
mov ret0 = str
|
|
and tmp = 7, str // tmp = str % 8
|
|
mux1 chrx8 = chr, @brcst
|
|
extr.u chr = chr, 0, 8 // retain only the last byte
|
|
cmp.ne p8, p0 = r0, r0 // clear p8
|
|
;;
|
|
sub loopcnt = 8, tmp // loopcnt = 8 - tmp
|
|
cmp.eq p6, p0 = tmp, r0
|
|
(p6) br.cond.sptk .str_aligned;;
|
|
adds loopcnt = -1, loopcnt;;
|
|
mov ar.lc = loopcnt
|
|
.l1:
|
|
ld1 val2 = [ret0], 1
|
|
;;
|
|
cmp.eq p6, p0 = val2, chr
|
|
cmp.eq p7, p0 = val2, r0
|
|
(p6) br.cond.spnt .restore_and_exit
|
|
(p7) br.cond.spnt .notfound
|
|
br.cloop.sptk .l1
|
|
.str_aligned:
|
|
ld8 val1 = [ret0], 8;;
|
|
nop.b 0
|
|
nop.b 0
|
|
.l2:
|
|
ld8.s val2 = [ret0], 8 // don't bomb out here
|
|
czx1.r pos0 = val1
|
|
xor tmp = val1, chrx8 // if val1 contains chr, tmp will
|
|
;; // contain a zero in its position
|
|
czx1.r poschr = tmp
|
|
cmp.ne p6, p0 = 8, pos0
|
|
;;
|
|
cmp.ne p7, p0 = 8, poschr
|
|
(p7) br.cond.spnt .foundit
|
|
(p6) br.cond.spnt .notfound
|
|
chk.s val2, .recovery
|
|
.back:
|
|
mov val1 = val2
|
|
br.cond.dptk .l2
|
|
.foundit:
|
|
(p6) cmp.lt p8, p0 = pos0, poschr // we found chr and null in the word
|
|
(p8) br.cond.spnt .notfound // null was found before chr
|
|
add ret0 = ret0, poschr ;;
|
|
adds ret0 = -15, ret0 ;; // should be -16, but we decrement
|
|
.restore_and_exit: // ret0 in the next instruction
|
|
adds ret0 = -1, ret0 // ret0 was pointing 1 char too far
|
|
mov ar.lc = saved_lc // restore the loop counter
|
|
br.ret.sptk.many b0
|
|
.notfound:
|
|
mov ret0 = r0 // return NULL if null was found
|
|
mov ar.lc = saved_lc
|
|
br.ret.sptk.many b0
|
|
.recovery:
|
|
adds ret0 = -8, ret0;;
|
|
ld8 val2 = [ret0], 8 // bomb out here
|
|
br.cond.sptk .back
|
|
END(strchr)
|
|
|
|
weak_alias (strchr, index)
|
|
libc_hidden_builtin_def (strchr)
|