linux/arch/tile/include/asm/bitops.h
Chris Metcalf 9f1d62bed7 tile: fix bug where fls(0) was not returning 0
This is because __builtin_clz(0) returns 64 for the "undefined" case
of 0, since the builtin just does a right-shift 32 and "clz" instruction.
So, use the alpha approach of casting to u32 and using __builtin_clzll().

Cc: stable@vger.kernel.org
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
2012-05-25 15:00:43 -04:00

129 lines
3.1 KiB
C

/*
* Copyright 1992, Linus Torvalds.
* Copyright 2010 Tilera Corporation. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#ifndef _ASM_TILE_BITOPS_H
#define _ASM_TILE_BITOPS_H
#include <linux/types.h>
#ifndef _LINUX_BITOPS_H
#error only <linux/bitops.h> can be included directly
#endif
#ifdef __tilegx__
#include <asm/bitops_64.h>
#else
#include <asm/bitops_32.h>
#endif
/**
* __ffs - find first set bit in word
* @word: The word to search
*
* Undefined if no set bit exists, so code should check against 0 first.
*/
static inline unsigned long __ffs(unsigned long word)
{
return __builtin_ctzl(word);
}
/**
* ffz - find first zero bit in word
* @word: The word to search
*
* Undefined if no zero exists, so code should check against ~0UL first.
*/
static inline unsigned long ffz(unsigned long word)
{
return __builtin_ctzl(~word);
}
/**
* __fls - find last set bit in word
* @word: The word to search
*
* Undefined if no set bit exists, so code should check against 0 first.
*/
static inline unsigned long __fls(unsigned long word)
{
return (sizeof(word) * 8) - 1 - __builtin_clzl(word);
}
/**
* ffs - find first set bit in word
* @x: the word to search
*
* This is defined the same way as the libc and compiler builtin ffs
* routines, therefore differs in spirit from the other bitops.
*
* ffs(value) returns 0 if value is 0 or the position of the first
* set bit if value is nonzero. The first (least significant) bit
* is at position 1.
*/
static inline int ffs(int x)
{
return __builtin_ffs(x);
}
static inline int fls64(__u64 w)
{
return (sizeof(__u64) * 8) - __builtin_clzll(w);
}
/**
* fls - find last set bit in word
* @x: the word to search
*
* This is defined in a similar way as the libc and compiler builtin
* ffs, but returns the position of the most significant set bit.
*
* fls(value) returns 0 if value is 0 or the position of the last
* set bit if value is nonzero. The last (most significant) bit is
* at position 32.
*/
static inline int fls(int x)
{
return fls64((unsigned int) x);
}
static inline unsigned int __arch_hweight32(unsigned int w)
{
return __builtin_popcount(w);
}
static inline unsigned int __arch_hweight16(unsigned int w)
{
return __builtin_popcount(w & 0xffff);
}
static inline unsigned int __arch_hweight8(unsigned int w)
{
return __builtin_popcount(w & 0xff);
}
static inline unsigned long __arch_hweight64(__u64 w)
{
return __builtin_popcountll(w);
}
#include <asm-generic/bitops/const_hweight.h>
#include <asm-generic/bitops/lock.h>
#include <asm-generic/bitops/find.h>
#include <asm-generic/bitops/sched.h>
#include <asm-generic/bitops/non-atomic.h>
#include <asm-generic/bitops/le.h>
#endif /* _ASM_TILE_BITOPS_H */