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Use clz / dclz on MIPS32 / MIPS64 processors.

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Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Ralf Baechle 2005-07-12 12:50:30 +00:00
parent e5de3b4687
commit 6590326505
1 changed files with 115 additions and 22 deletions
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137
include/asm-mips/bitops.h
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@ -546,17 +546,60 @@ static inline int test_bit(unsigned long nr, const volatile unsigned long *addr)
return 1UL & (addr[nr >> SZLONG_LOG] >> (nr & SZLONG_MASK));
}
#ifdef CONFIG_CPU_MIPS32_R1
/*
* ffz - find first zero in word.
* Return the bit position (0..31) of the most significant 1 bit in a word
* Returns -1 if no 1 bit exists
*/
static __inline__ int __ilog2(unsigned long x)
{
int lz;
__asm__ (
" .set push \n"
" .set mips32 \n"
" clz %0, %1 \n"
" .set pop \n"
: "=r" (lz)
: "r" (x));
return 31 - lz;
}
#elif defined(CONFIG_CPU_MIPS64_R1)
/*
* Return the bit position (0..63) of the most significant 1 bit in a word
* Returns -1 if no 1 bit exists
*/
static __inline__ int __ilog2(unsigned long x)
{
int lz;
__asm__ (
" .set push \n"
" .set mips64 \n"
" dclz %0, %1 \n"
" .set pop \n"
: "=r" (lz)
: "r" (x));
return 63 - lz;
}
#endif
/*
* __ffs - find first bit in word.
* @word: The word to search
*
* Undefined if no zero exists, so code should check against ~0UL first.
* Returns 0..SZLONG-1
* Undefined if no bit exists, so code should check against 0 first.
*/
static inline unsigned long ffz(unsigned long word)
static inline unsigned long __ffs(unsigned long word)
{
#if defined(CONFIG_CPU_MIPS32_R1) || defined(CONFIG_CPU_MIPS64_R1)
return __ilog2(word & -word);
#else
int b = 0, s;
word = ~word;
#ifdef CONFIG_32BIT
s = 16; if (word << 16 != 0) s = 0; b += s; word >>= s;
s = 8; if (word << 24 != 0) s = 0; b += s; word >>= s;
@ -572,26 +615,87 @@ static inline unsigned long ffz(unsigned long word)
s = 2; if (word << 62 != 0) s = 0; b += s; word >>= s;
s = 1; if (word << 63 != 0) s = 0; b += s;
#endif
return b;
#endif
}
/*
* __ffs - find first bit in word.
* ffs - find first bit set.
* @word: The word to search
*
* Undefined if no bit exists, so code should check against 0 first.
* Returns 1..SZLONG
* Returns 0 if no bit exists
*/
static inline unsigned long __ffs(unsigned long word)
static inline unsigned long ffs(unsigned long word)
{
return ffz(~word);
if (!word)
return 0;
return __ffs(word) + 1;
}
/*
* fls: find last bit set.
* ffz - find first zero 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 __ffs (~word);
}
/*
* flz - find last zero in word.
* @word: The word to search
*
* Returns 0..SZLONG-1
* Undefined if no zero exists, so code should check against ~0UL first.
*/
static inline unsigned long flz(unsigned long word)
{
#if defined(CONFIG_CPU_MIPS32_R1) || defined(CONFIG_CPU_MIPS64_R1)
return __ilog2(~word);
#else
#if defined(CONFIG_32BIT)
int r = 31, s;
word = ~word;
s = 16; if ((word & 0xffff0000)) s = 0; r -= s; word <<= s;
s = 8; if ((word & 0xff000000)) s = 0; r -= s; word <<= s;
s = 4; if ((word & 0xf0000000)) s = 0; r -= s; word <<= s;
s = 2; if ((word & 0xc0000000)) s = 0; r -= s; word <<= s;
s = 1; if ((word & 0x80000000)) s = 0; r -= s;
#endif
#if defined(CONFIG_64BIT)
int r = 63, s;
word = ~word;
s = 32; if ((word & 0xffffffff00000000UL)) s = 0; r -= s; word <<= s;
s = 16; if ((word & 0xffff000000000000UL)) s = 0; r -= s; word <<= s;
s = 8; if ((word & 0xff00000000000000UL)) s = 0; r -= s; word <<= s;
s = 4; if ((word & 0xf000000000000000UL)) s = 0; r -= s; word <<= s;
s = 2; if ((word & 0xc000000000000000UL)) s = 0; r -= s; word <<= s;
s = 1; if ((word & 0x8000000000000000UL)) s = 0; r -= s;
#endif
return r;
#endif
}
/*
* fls - find last bit set.
* @word: The word to search
*
* Returns 1..SZLONG
* Returns 0 if no bit exists
*/
static inline unsigned long fls(unsigned long word)
{
if (word == 0)
return 0;
return flz(~word) + 1;
}
#define fls(x) generic_fls(x)
/*
* find_next_zero_bit - find the first zero bit in a memory region
@ -727,17 +831,6 @@ static inline int sched_find_first_bit(const unsigned long *b)
#endif
}
/*
* ffs - find first bit set
* @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 above ffz (man ffs).
*/
#define ffs(x) generic_ffs(x)
/*
* hweightN - returns the hamming weight of a N-bit word
* @x: the word to weigh