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/* $NetBSD: ffs.S,v 1.3 1996/10/17 03:08:13 cgd Exp $ */
/*
* Copyright (c) 1995 Christopher G. Demetriou
* All rights reserved.
*
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Christopher G. Demetriou
* for the NetBSD Project.
* 4. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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>
__FBSDID("$FreeBSD$");
ENTRY(ffs, 1)
sxt4 r14=in0 ;;
cmp.eq p6,p0=r14,r0
(p6) br.dpnt.few Lallzero
/*
* Initialize return value (ret0), and set up r15 so that it
* contains the mask with only the lowest bit set.
*/
sub r15=r0,r14
mov ret0=1 ;;
and r15=r14,r15 ;;
extr.u r16=r15,0,8 ;;
cmp.ne p6,p0=r0,r16
(p6) br.dptk.few Ldo8
/*
* If lower 16 bits empty, add 16 to result and use upper 16.
*/
extr.u r16=r15,0,16 ;;
cmp.ne p6,p0=r0,r16
(p6) br.dptk.few Ldo16
extr.u r15=r15,16,16
add ret0=16,ret0 ;;
Ldo16:
/*
* If lower 8 bits empty, add 8 to result and use upper 8.
*/
extr.u r16=r15,0,8 ;;
cmp.ne p6,p0=r0,r16
(p6) br.dptk.few Ldo8
extr.u r15=r15,8,24
add ret0=8,ret0 ;;
Ldo8:
and r16=0x0f,r15 /* lower 4 of 8 empty? */
and r17=0x33,r15 /* lower 2 of each 4 empty? */
and r18=0x55,r15 ;; /* lower 1 of each 2 empty? */
cmp.ne p6,p0=r16,r0
cmp.ne p7,p0=r17,r0
cmp.ne p8,p0=r18,r0
/* If lower 4 bits empty, add 4 to result. */
(p6) br.dptk.few Ldo4
add ret0=4,ret0 ;;
Ldo4: /* If lower 2 bits of each 4 empty, add 2 to result. */
(p7) br.dptk.few Ldo2
add ret0=2,ret0 ;;
Ldo2: /* If lower bit of each 2 empty, add 1 to result. */
(p8) br.dptk.few Ldone
add ret0=1,ret0
Ldone:
br.ret.sptk.few rp
Lallzero:
mov ret0=0
br.ret.sptk.few rp
END(ffs)
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