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arm: Add optimized ffs for armv6t2

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Richard Henderson 2013-02-13 12:06:42 -08:00
parent 79fd873111
commit 5695fc848f
3 changed files with 88 additions and 0 deletions
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3
ports/ChangeLog.arm
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2013-03-06 Richard Henderson <rth@redhat.com>
* sysdeps/arm/armv6t2/ffs.S: New file.
* sysdeps/arm/armv6t2/ffsll.S: New file.
* sysdeps/arm/sysdep.h (ARCH_HAS_HARD_TP): New macro.
(GET_TLS): Use hard-tp if ARCH_HAS_HARD_TP.
* sysdeps/unix/sysv/linux/arm/aeabi_read_tp.S: Likewise.

35
ports/sysdeps/arm/armv6t2/ffs.S Normal file
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/* ffs -- find first set bit in an int, from least significant end.
Copyright (C) 2013 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/>. */
#include <sysdep.h>
.syntax unified
.text
ENTRY (__ffs)
cmp r0, #0
rbit r0, r0
itt ne
clzne r0, r0
addne r0, r0, #1
bx lr
END (__ffs)
weak_alias (__ffs, ffs)
weak_alias (__ffs, ffsl)
libc_hidden_builtin_def (ffs)

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ports/sysdeps/arm/armv6t2/ffsll.S Normal file
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/* ffsll -- find first set bit in a long long, from least significant end.
Copyright (C) 2013 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/>. */
#include <sysdep.h>
.syntax unified
.text
ENTRY (ffsll)
@ If low part is 0, operate on the high part. Ensure that the
@ word on which we operate is in r0. Set r2 to the bit offset
@ of the word being considered. Set the flags for the word
@ being operated on.
#ifdef __ARMEL__
cmp r0, #0
itee ne
movne r2, #0
moveq r2, #32
movseq r0, r1
#else
cmp r1, #0
ittee ne
movne r2, #0
movne r0, r1
moveq r2, #32
cmpeq r0, #0
#endif
@ Perform the ffs on r0.
rbit r0, r0
ittt ne
clzne r0, r0
addne r2, r2, #1
addne r0, r0, r2
bx lr
END (ffsll)