mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-23 13:30:06 +00:00
170 lines
4.2 KiB
ArmAsm
170 lines
4.2 KiB
ArmAsm
/* Copyright (C) 2010-2016 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
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
/*
|
|
Assumes:
|
|
ARMv6T2, AArch32
|
|
|
|
*/
|
|
|
|
#include <arm-features.h> /* This might #define NO_THUMB. */
|
|
#include <sysdep.h>
|
|
|
|
#ifdef __ARMEB__
|
|
#define S2LO lsl
|
|
#define S2HI lsr
|
|
#else
|
|
#define S2LO lsr
|
|
#define S2HI lsl
|
|
#endif
|
|
|
|
#ifndef NO_THUMB
|
|
/* This code is best on Thumb. */
|
|
.thumb
|
|
#else
|
|
/* Using bne.w explicitly is desirable in Thumb mode because it helps
|
|
align the following label without a nop. In ARM mode there is no
|
|
such difference. */
|
|
.macro bne.w label
|
|
bne \label
|
|
.endm
|
|
|
|
/* This clobbers the condition codes, which the real Thumb cbnz instruction
|
|
does not do. But it doesn't matter for any of the uses here. */
|
|
.macro cbnz reg, label
|
|
cmp \reg, #0
|
|
bne \label
|
|
.endm
|
|
#endif
|
|
|
|
/* Parameters and result. */
|
|
#define srcin r0
|
|
#define result r0
|
|
|
|
/* Internal variables. */
|
|
#define src r1
|
|
#define data1a r2
|
|
#define data1b r3
|
|
#define const_m1 r12
|
|
#define const_0 r4
|
|
#define tmp1 r4 /* Overlaps const_0 */
|
|
#define tmp2 r5
|
|
|
|
.text
|
|
.p2align 6
|
|
ENTRY(strlen)
|
|
sfi_pld srcin, #0
|
|
strd r4, r5, [sp, #-8]!
|
|
cfi_adjust_cfa_offset (8)
|
|
cfi_rel_offset (r4, 0)
|
|
cfi_rel_offset (r5, 4)
|
|
cfi_remember_state
|
|
bic src, srcin, #7
|
|
mvn const_m1, #0
|
|
ands tmp1, srcin, #7 /* (8 - bytes) to alignment. */
|
|
sfi_pld src, #32
|
|
bne.w .Lmisaligned8
|
|
mov const_0, #0
|
|
mov result, #-8
|
|
.Lloop_aligned:
|
|
/* Bytes 0-7. */
|
|
sfi_breg src, \
|
|
ldrd data1a, data1b, [\B]
|
|
sfi_pld src, #64
|
|
add result, result, #8
|
|
.Lstart_realigned:
|
|
uadd8 data1a, data1a, const_m1 /* Saturating GE<0:3> set. */
|
|
sel data1a, const_0, const_m1 /* Select based on GE<0:3>. */
|
|
uadd8 data1b, data1b, const_m1
|
|
sel data1b, data1a, const_m1 /* Only used if d1a == 0. */
|
|
cbnz data1b, .Lnull_found
|
|
|
|
/* Bytes 8-15. */
|
|
sfi_breg src, \
|
|
ldrd data1a, data1b, [\B, #8]
|
|
uadd8 data1a, data1a, const_m1 /* Saturating GE<0:3> set. */
|
|
add result, result, #8
|
|
sel data1a, const_0, const_m1 /* Select based on GE<0:3>. */
|
|
uadd8 data1b, data1b, const_m1
|
|
sel data1b, data1a, const_m1 /* Only used if d1a == 0. */
|
|
cbnz data1b, .Lnull_found
|
|
|
|
/* Bytes 16-23. */
|
|
sfi_breg src, \
|
|
ldrd data1a, data1b, [\B, #16]
|
|
uadd8 data1a, data1a, const_m1 /* Saturating GE<0:3> set. */
|
|
add result, result, #8
|
|
sel data1a, const_0, const_m1 /* Select based on GE<0:3>. */
|
|
uadd8 data1b, data1b, const_m1
|
|
sel data1b, data1a, const_m1 /* Only used if d1a == 0. */
|
|
cbnz data1b, .Lnull_found
|
|
|
|
/* Bytes 24-31. */
|
|
sfi_breg src, \
|
|
ldrd data1a, data1b, [\B, #24]
|
|
add src, src, #32
|
|
uadd8 data1a, data1a, const_m1 /* Saturating GE<0:3> set. */
|
|
add result, result, #8
|
|
sel data1a, const_0, const_m1 /* Select based on GE<0:3>. */
|
|
uadd8 data1b, data1b, const_m1
|
|
sel data1b, data1a, const_m1 /* Only used if d1a == 0. */
|
|
cmp data1b, #0
|
|
beq .Lloop_aligned
|
|
|
|
.Lnull_found:
|
|
cmp data1a, #0
|
|
itt eq
|
|
addeq result, result, #4
|
|
moveq data1a, data1b
|
|
#ifndef __ARMEB__
|
|
rev data1a, data1a
|
|
#endif
|
|
clz data1a, data1a
|
|
ldrd r4, r5, [sp], #8
|
|
cfi_adjust_cfa_offset (-8)
|
|
cfi_restore (r4)
|
|
cfi_restore (r5)
|
|
add result, result, data1a, lsr #3 /* Bits -> Bytes. */
|
|
DO_RET(lr)
|
|
|
|
.Lmisaligned8:
|
|
cfi_restore_state
|
|
sfi_breg src, \
|
|
ldrd data1a, data1b, [\B]
|
|
and tmp2, tmp1, #3
|
|
rsb result, tmp1, #0
|
|
lsl tmp2, tmp2, #3 /* Bytes -> bits. */
|
|
tst tmp1, #4
|
|
sfi_pld src, #64
|
|
S2HI tmp2, const_m1, tmp2
|
|
#ifdef NO_THUMB
|
|
mvn tmp1, tmp2
|
|
orr data1a, data1a, tmp1
|
|
itt ne
|
|
orrne data1b, data1b, tmp1
|
|
#else
|
|
orn data1a, data1a, tmp2
|
|
itt ne
|
|
ornne data1b, data1b, tmp2
|
|
#endif
|
|
movne data1a, const_m1
|
|
mov const_0, #0
|
|
b .Lstart_realigned
|
|
|
|
END(strlen)
|
|
libc_hidden_builtin_def (strlen)
|