claunia/flac
1
0
Fork 0
mirror of https://github.com/claunia/flac.git synced 2025-12-16 18:54:26 +00:00
Code Issues Packages Projects Releases Wiki Activity

add fixed-point functions

Browse Source
This commit is contained in:
Josh Coalson
2004-11-09 01:25:14 +00:00
parent 375810ebdd
commit f719813b0f
2 changed files with 343 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

39
src/libFLAC/include/private/float.h
View File

@@ -36,6 +36,8 @@
#include <config.h>
#endif
#include "FLAC/ordinals.h"
/*
* These typedefs make it easier to ensure that integer versions of
* the library really only contain integer operations. All the code
@@ -49,6 +51,43 @@
typedef double FLAC__double;
typedef float FLAC__float;
typedef float FLAC__real;
#else
/*
* The convention for FLAC__fixedpoint is to use the upper 16 bits
* for the integer part and lower 16 bits for the fractional part.
*/
typedef FLAC__int32 FLAC__fixedpoint;
extern const FLAC__fixedpoint FLAC__FP_ZERO;
extern const FLAC__fixedpoint FLAC__FP_ONE_HALF;
extern const FLAC__fixedpoint FLAC__FP_ONE;
extern const FLAC__fixedpoint FLAC__FP_LN2;
extern const FLAC__fixedpoint FLAC__FP_E;
#define FLAC__fixedpoint_trunc(x) ((x)>>16)
#define FLAC__fixedpoint_mul(x, y) ( (FLAC__fixedpoint) ( ((FLAC__int64)(x)*(FLAC__int64)(y)) >> 16 ) )
#define FLAC__fixedpoint_div(x, y) ( (FLAC__fixedpoint) ( ( ((FLAC__int64)(x)<<32) / (FLAC__int64)(y) ) >> 16 ) )
/*
* FLAC__fixedpoint_log2()
* --------------------------------------------------------------------
* Returns the base-2 logarithm of the fixed-point number 'x' using an
* algorithm by Knuth for x >= 1.0
*
* 'fracbits' is the number of fractional bits of 'x'. 'fracbits' must
* be < 32 and evenly divisible by 4 (0 is OK but not very precise).
*
* 'precision' roughly limits the number of iterations that are done;
* use (unsigned)(-1) for maximum precision.
*
* If 'x' is less than one -- that is, x < (1<<fracbits) -- then this
* function will punt and return 0.
*
* The return value will also have 'fracbits' fractional bits.
*/
FLAC__uint32 FLAC__fixedpoint_log2(FLAC__uint32 x, unsigned fracbits, unsigned precision);
#endif
#endif