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util: move bitcount to bitscan.h

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bitcount is free from the pipe header dependencies that make u_math.h hard
to include by non-gallium specific code, so move it to bitscan.h. bitscan.h
is included by u_math.h so existing references will continue working.

Signed-off-by: Kevin Strasser <kevin.strasser@intel.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
This commit is contained in:
Kevin Strasser 2019-06-14 14:27:53 -07:00 • committed by Adam Jackson
parent 5a747306ce
commit 3562f48c9d
2 changed files with 32 additions and 36 deletions
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32
src/util/bitscan.h
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@ -286,6 +286,38 @@ u_bit_consecutive64(unsigned start, unsigned count)
return (((uint64_t)1 << count) - 1) << start;
}
/**
* Return number of bits set in n.
*/
static inline unsigned
util_bitcount(unsigned n)
{
#if defined(HAVE___BUILTIN_POPCOUNT)
return __builtin_popcount(n);
#else
/* K&R classic bitcount.
*
* For each iteration, clear the LSB from the bitfield.
* Requires only one iteration per set bit, instead of
* one iteration per bit less than highest set bit.
*/
unsigned bits;
for (bits = 0; n; bits++) {
n &= n - 1;
}
return bits;
#endif
}
static inline unsigned
util_bitcount64(uint64_t n)
{
#ifdef HAVE___BUILTIN_POPCOUNTLL
return __builtin_popcountll(n);
#else
return util_bitcount(n) + util_bitcount(n >> 32);
#endif
}
#ifdef __cplusplus
}

36
src/util/u_math.h
View file

@ -548,42 +548,6 @@ util_next_power_of_two64(uint64_t x)
#endif
}
/**
* Return number of bits set in n.
*/
static inline unsigned
util_bitcount(unsigned n)
{
#if defined(HAVE___BUILTIN_POPCOUNT)
return __builtin_popcount(n);
#else
/* K&R classic bitcount.
*
* For each iteration, clear the LSB from the bitfield.
* Requires only one iteration per set bit, instead of
* one iteration per bit less than highest set bit.
*/
unsigned bits;
for (bits = 0; n; bits++) {
n &= n - 1;
}
return bits;
#endif
}
static inline unsigned
util_bitcount64(uint64_t n)
{
#ifdef HAVE___BUILTIN_POPCOUNTLL
return __builtin_popcountll(n);
#else
return util_bitcount(n) + util_bitcount(n >> 32);
#endif
}
/**
* Reverse bits in n
* Algorithm taken from: