110 lines
3.3 KiB
C
110 lines
3.3 KiB
C
/* v2/ffs.h - ARCv2 public nanokernel find-first-set interface */
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/*
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* Copyright (c) 2014 Wind River Systems, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1) Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* 2) Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* 3) Neither the name of Wind River Systems nor the names of its contributors
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* may be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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DESCRIPTION
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ARC-specific nanokernel ffs interface. Included by ARC/arch.h.
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*/
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#ifndef _ARCH_ARC_V2_FFS_H_
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#define _ARCH_ARC_V2_FFS_H_
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#ifdef _ASMLANGUAGE
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GTEXT(nanoFfsLsb);
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GTEXT(nanoFfsMsb);
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#else
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extern unsigned nanoFfsLsb(unsigned int);
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extern unsigned nanoFfsMsb(unsigned int);
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/*******************************************************************************
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*
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* nanoFfsMsb_inline - Find First Set bit (searching from most significant bit)
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*
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* This routine finds the first bit set in the argument passed it and returns
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* the index of that bit. Bits are numbered starting at 1 from the least
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* significant bit. A return value of zero indicates that the value passed
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* is zero.
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*
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* RETURNS: most significant bit set
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*/
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#if defined(__GNUC__)
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static ALWAYS_INLINE unsigned int nanoFfsMsb_inline(unsigned int op)
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{
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unsigned int bit;
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__asm__ volatile(
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/* see explanation in ffs.s */
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"fls.f %0, %1;\n\t"
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"add.nz %0, %0, 1;\n\t"
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: "=r"(bit)
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: "r"(op));
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return bit;
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}
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#endif
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/*******************************************************************************
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*
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* nanoFfsLsb - find first set bit (searching from the least significant bit)
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*
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* This routine finds the first bit set in the argument passed it and
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* returns the index of that bit. Bits are numbered starting
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* at 1 from the least significant bit. A return value of zero indicates that
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* the value passed is zero.
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*
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* RETURNS: least significant bit set
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*/
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#if defined(__GNUC__)
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static ALWAYS_INLINE unsigned int nanoFfsLsb_inline(unsigned int op)
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{
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unsigned int bit;
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__asm__ volatile(
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/* see explanation in ffs.s */
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"ffs.f %0, %1;\n\t"
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"add.nz %0, %0, 1;\n\t"
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"mov.z %0, 0;\n\t"
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: "=&r"(bit)
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: "r"(op));
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return bit;
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}
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#endif
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#endif /* _ASMLANGUAGE */
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#endif /* _ARCH_ARC_V2_FFS_H_ */
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