minix/common/lib/libc/arch/m68k/string/ffs.S

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/* $NetBSD: ffs.S,v 1.6 2013/09/07 19:06:29 chs Exp $ */
/*-
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* the Systems Programming Group of the University of Utah Computer
* Science Department.
*
* 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.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*/
#include <machine/asm.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
RCSID("from: @(#)ffs.s 5.1 (Berkeley) 5/12/90")
#else
RCSID("$NetBSD: ffs.S,v 1.6 2013/09/07 19:06:29 chs Exp $")
#endif
#endif /* LIBC_SCCS and not lint */
/* bit = ffs(value) */
WEAK_ALIAS(__ffssi2,ffs)
#if (!defined(__mc68010__) && !defined(__mcoldfire__)) || defined(__mcfisac__)
ENTRY(ffs)
movl 4(%sp),%d0
movl %d0,%d1
negl %d0
andl %d0,%d1
movql #32,%d0
#if defined(__mcfisac__)
ff1.l %d1 | count leading zeros
#else
bfffo %d1{#0:#32},%d1
#endif
subl %d1,%d0
rts
END(ffs)
#elif defined(__mcoldfire__)
ENTRY(ffs)
clrl %d0
movl 4(%sp),%d1
jeq .L2 | return 0 if 0
.L1:
addql #1,%d0
lsrl #1,%d1 | shift low bit into carry
jcc .L1 | keep looping while carry is clear.
.L2:
rts
#else /* __mc68010__ */
ENTRY(ffs)
movl 4(%sp),%d0
jeq .L2
movql #31,%d1
.L1:
lsrl #1,%d0
dbcs %d1,.L1
movql #32,%d0
subl %d1,%d0
.L2:
rts
END(ffs)
#endif /* __mc68010__ */