193 lines
4.3 KiB
C
193 lines
4.3 KiB
C
/*
|
|
* Copyright (c) 2008-2012 Stefan Krah. 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.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
|
|
*/
|
|
|
|
|
|
#ifndef BITS_H
|
|
#define BITS_H
|
|
|
|
|
|
#include "mpdecimal.h"
|
|
#include <stdio.h>
|
|
|
|
|
|
/* Check if n is a power of 2. */
|
|
static inline int
|
|
ispower2(mpd_size_t n)
|
|
{
|
|
return n != 0 && (n & (n-1)) == 0;
|
|
}
|
|
|
|
#if defined(ANSI)
|
|
/*
|
|
* Return the most significant bit position of n from 0 to 31 (63).
|
|
* Assumptions: n != 0.
|
|
*/
|
|
static inline int
|
|
mpd_bsr(mpd_size_t n)
|
|
{
|
|
int pos = 0;
|
|
mpd_size_t tmp;
|
|
|
|
#ifdef CONFIG_64
|
|
tmp = n >> 32;
|
|
if (tmp != 0) { n = tmp; pos += 32; }
|
|
#endif
|
|
tmp = n >> 16;
|
|
if (tmp != 0) { n = tmp; pos += 16; }
|
|
tmp = n >> 8;
|
|
if (tmp != 0) { n = tmp; pos += 8; }
|
|
tmp = n >> 4;
|
|
if (tmp != 0) { n = tmp; pos += 4; }
|
|
tmp = n >> 2;
|
|
if (tmp != 0) { n = tmp; pos += 2; }
|
|
tmp = n >> 1;
|
|
if (tmp != 0) { n = tmp; pos += 1; }
|
|
|
|
return pos + (int)n - 1;
|
|
}
|
|
|
|
/*
|
|
* Return the least significant bit position of n from 0 to 31 (63).
|
|
* Assumptions: n != 0.
|
|
*/
|
|
static inline int
|
|
mpd_bsf(mpd_size_t n)
|
|
{
|
|
int pos;
|
|
|
|
#ifdef CONFIG_64
|
|
pos = 63;
|
|
if (n & 0x00000000FFFFFFFFULL) { pos -= 32; } else { n >>= 32; }
|
|
if (n & 0x000000000000FFFFULL) { pos -= 16; } else { n >>= 16; }
|
|
if (n & 0x00000000000000FFULL) { pos -= 8; } else { n >>= 8; }
|
|
if (n & 0x000000000000000FULL) { pos -= 4; } else { n >>= 4; }
|
|
if (n & 0x0000000000000003ULL) { pos -= 2; } else { n >>= 2; }
|
|
if (n & 0x0000000000000001ULL) { pos -= 1; }
|
|
#else
|
|
pos = 31;
|
|
if (n & 0x000000000000FFFFUL) { pos -= 16; } else { n >>= 16; }
|
|
if (n & 0x00000000000000FFUL) { pos -= 8; } else { n >>= 8; }
|
|
if (n & 0x000000000000000FUL) { pos -= 4; } else { n >>= 4; }
|
|
if (n & 0x0000000000000003UL) { pos -= 2; } else { n >>= 2; }
|
|
if (n & 0x0000000000000001UL) { pos -= 1; }
|
|
#endif
|
|
return pos;
|
|
}
|
|
/* END ANSI */
|
|
|
|
#elif defined(ASM)
|
|
/*
|
|
* Bit scan reverse. Assumptions: a != 0.
|
|
*/
|
|
static inline int
|
|
mpd_bsr(mpd_size_t a)
|
|
{
|
|
mpd_size_t retval;
|
|
|
|
__asm__ (
|
|
#ifdef CONFIG_64
|
|
"bsrq %1, %0\n\t"
|
|
#else
|
|
"bsr %1, %0\n\t"
|
|
#endif
|
|
:"=r" (retval)
|
|
:"r" (a)
|
|
:"cc"
|
|
);
|
|
|
|
return (int)retval;
|
|
}
|
|
|
|
/*
|
|
* Bit scan forward. Assumptions: a != 0.
|
|
*/
|
|
static inline int
|
|
mpd_bsf(mpd_size_t a)
|
|
{
|
|
mpd_size_t retval;
|
|
|
|
__asm__ (
|
|
#ifdef CONFIG_64
|
|
"bsfq %1, %0\n\t"
|
|
#else
|
|
"bsf %1, %0\n\t"
|
|
#endif
|
|
:"=r" (retval)
|
|
:"r" (a)
|
|
:"cc"
|
|
);
|
|
|
|
return (int)retval;
|
|
}
|
|
/* END ASM */
|
|
|
|
#elif defined(MASM)
|
|
#include <intrin.h>
|
|
/*
|
|
* Bit scan reverse. Assumptions: a != 0.
|
|
*/
|
|
static inline int __cdecl
|
|
mpd_bsr(mpd_size_t a)
|
|
{
|
|
unsigned long retval;
|
|
|
|
#ifdef CONFIG_64
|
|
_BitScanReverse64(&retval, a);
|
|
#else
|
|
_BitScanReverse(&retval, a);
|
|
#endif
|
|
|
|
return (int)retval;
|
|
}
|
|
|
|
/*
|
|
* Bit scan forward. Assumptions: a != 0.
|
|
*/
|
|
static inline int __cdecl
|
|
mpd_bsf(mpd_size_t a)
|
|
{
|
|
unsigned long retval;
|
|
|
|
#ifdef CONFIG_64
|
|
_BitScanForward64(&retval, a);
|
|
#else
|
|
_BitScanForward(&retval, a);
|
|
#endif
|
|
|
|
return (int)retval;
|
|
}
|
|
/* END MASM (_MSC_VER) */
|
|
#else
|
|
#error "missing preprocessor definitions"
|
|
#endif /* BSR/BSF */
|
|
|
|
|
|
#endif /* BITS_H */
|
|
|
|
|
|
|