/*-
* Copyright (c) 2010 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
WEAK_ALIAS(__ffssi2,ffs)
#if __mips == 64 || __mips == 32
LEAF(ffs)
#ifndef _LP64
XLEAF(ffsl)
#endif
.set push
.set mips32
li v1, 32
#if __mips == 64
sll a0, a0, 0
#endif
negu a1, a0
and a0, a1
clz v0, a0
j ra
subu v0, v1, v0
.set pop
END(ffs)
#if defined(_LP64) && __mips == 64
LEAF(ffsl)
li v1, 64
negu a1, a0
and a0, a1
dclz v0, a0
j ra
subu v0, v1, v0
END(ffsl)
#endif
#else /* __mips != 64 && __mips != 32 */
#ifdef _LP64
XLEAF(ffsl)
beqz a0, 6f # fast escape if 0
li v0, 0
li v0, 1
li a3, 0xffffffff # initial mask
b 1f
li a2, 32 # bit count of mask
#endif /* _LP64 */
LEAF(ffs)
#ifndef _LP64
XLEAF(ffsl)
#endif /* !_LP64 */
beqz a0, 6f
li v0, 0
li v0, 1
li a3, 0xffff # initial mask
li a2, 16 # bit count of mask
1:
and v1, a0, a3 # focus no lower half of bits left
bnez v1, 2f # any of the lower half set?
nop
addu v0, a2 # nope, then bit is in the upper half
#ifdef _LP64
dsrlv a0, a0, a2 # discard low bits
#else
srlv a0, a0, a2 # discard low bits
#endif
2:
srl a2, 1 # divide bit count by 2
bnez a2, 1b # still bits left to text?
srlv a3, a3, a2 # shrink mask in half
6:
j ra
nop
END(ffs)
#endif /* __mips == 64 || __mips == 32 */
