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bitmath.h: Cleanups

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* Drop support from MSVC earlier than 2005.
* Make types of FLAC__clz_uint32() and FLAC__clz_soft_uint32() the same.
* Remove un-needed parens.
* Cleanup FLAC__bitmath_ilog2_wide().

Patch-from: lvqcl <lvqcl.mail@gmail.com>
This commit is contained in:
Erik de Castro Lopo 2015-12-29 21:31:24 +11:00
parent 46d3a4c6f1
commit cf7f1b5a02
1 changed files with 12 additions and 14 deletions
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26
src/libFLAC/include/private/bitmath.h
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@ -36,16 +36,14 @@
#include "FLAC/ordinals.h"
#include "FLAC/assert.h"
/* for CHAR_BIT */
#include <limits.h>
#include "share/compat.h"
#if defined(_MSC_VER) && (_MSC_VER >= 1400)
#if defined(_MSC_VER)
#include <intrin.h> /* for _BitScanReverse* */
#endif
/* Will never be emitted for MSVC, GCC, Intel compilers */
static inline unsigned int FLAC__clz_soft_uint32(unsigned int word)
static inline unsigned int FLAC__clz_soft_uint32(FLAC__uint32 word)
{
static const unsigned char byte_to_unary_table[] = {
8, 7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
@ -66,10 +64,10 @@ static inline unsigned int FLAC__clz_soft_uint32(unsigned int word)
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
};
return (word) > 0xffffff ? byte_to_unary_table[(word) >> 24] :
(word) > 0xffff ? byte_to_unary_table[(word) >> 16] + 8 :
(word) > 0xff ? byte_to_unary_table[(word) >> 8] + 16 :
byte_to_unary_table[(word)] + 24;
return word > 0xffffff ? byte_to_unary_table[word >> 24] :
word > 0xffff ? byte_to_unary_table[word >> 16] + 8 :
word > 0xff ? byte_to_unary_table[word >> 8] + 16 :
byte_to_unary_table[word] + 24;
}
static inline unsigned int FLAC__clz_uint32(FLAC__uint32 v)
@ -82,7 +80,7 @@ static inline unsigned int FLAC__clz_uint32(FLAC__uint32 v)
/* This will translate either to (bsr ^ 31U), clz , ctlz, cntlz, lzcnt depending on
* -march= setting or to a software routine in exotic machines. */
return __builtin_clz(v);
#elif defined(_MSC_VER) && (_MSC_VER >= 1400)
#elif defined(_MSC_VER)
{
unsigned long idx;
_BitScanReverse(&idx, v);
@ -129,14 +127,14 @@ static inline unsigned FLAC__bitmath_ilog2(FLAC__uint32 v)
FLAC__ASSERT(v > 0);
#if defined(__INTEL_COMPILER)
return _bit_scan_reverse(v);
#elif defined(_MSC_VER) && (_MSC_VER >= 1400)
#elif defined(_MSC_VER)
{
unsigned long idx;
_BitScanReverse(&idx, v);
return idx;
}
#else
return sizeof(FLAC__uint32) * CHAR_BIT - 1 - FLAC__clz_uint32(v);
return FLAC__clz_uint32(v) ^ 31U;
#endif
}
@ -147,9 +145,9 @@ static inline unsigned FLAC__bitmath_ilog2_wide(FLAC__uint64 v)
{
FLAC__ASSERT(v > 0);
#if defined(__GNUC__) && (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
return sizeof(FLAC__uint64) * CHAR_BIT - 1 - __builtin_clzll(v);
return __builtin_clzll(v) ^ 63U;
/* Sorry, only supported in x64/Itanium.. and both have fast FPU which makes integer-only encoder pointless */
#elif (defined(_MSC_VER) && (_MSC_VER >= 1400)) && (defined(_M_IA64) || defined(_M_X64))
#elif (defined(__INTEL_COMPILER) || defined(_MSC_VER)) && (defined(_M_IA64) || defined(_M_X64))
{
unsigned long idx;
_BitScanReverse64(&idx, v);
@ -174,7 +172,7 @@ static inline unsigned FLAC__bitmath_ilog2_wide(FLAC__uint64 v)
v|= v>>16;
v|= v>>32;
v= (v>>1)+1;
return DEBRUIJN_IDX64[v*0x218A392CD3D5DBF>>58&0x3F];
return DEBRUIJN_IDX64[v*FLAC__U64L(0x218A392CD3D5DBF)>>58&0x3F];
}
#endif
}