diff options
Diffstat (limited to 'apps/codecs/libspeex/math_approx.h')
| -rw-r--r-- | apps/codecs/libspeex/math_approx.h | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/apps/codecs/libspeex/math_approx.h b/apps/codecs/libspeex/math_approx.h index 8421d634bb..4f61e8645a 100644 --- a/apps/codecs/libspeex/math_approx.h +++ b/apps/codecs/libspeex/math_approx.h @@ -45,8 +45,20 @@ #define spx_cos_norm(x) (cos((.5f*M_PI)*(x))) #define spx_atan atan -#endif +/** Generate a pseudo-random number */ +static inline spx_word16_t speex_rand(spx_word16_t std, spx_int32_t *seed) +{ + const unsigned int jflone = 0x3f800000; + const unsigned int jflmsk = 0x007fffff; + union {int i; float f;} ran; + *seed = 1664525 * *seed + 1013904223; + ran.i = jflone | (jflmsk & *seed); + ran.f -= 1.5; + return 3.4642*std*ran.f; +} + +#endif static inline spx_int16_t spx_ilog2(spx_uint32_t x) @@ -106,6 +118,15 @@ static inline spx_int16_t spx_ilog4(spx_uint32_t x) #ifdef FIXED_POINT +/** Generate a pseudo-random number */ +static inline spx_word16_t speex_rand(spx_word16_t std, spx_int32_t *seed) +{ + spx_word32_t res; + *seed = 1664525 * *seed + 1013904223; + res = MULT16_16(EXTRACT16(SHR32(*seed,16)),std); + return EXTRACT16(PSHR32(SUB32(res, SHR32(res, 3)),14)); +} + /* sqrt(x) ~= 0.22178 + 1.29227*x - 0.77070*x^2 + 0.25723*x^3 (for .25 < x < 1) */ /*#define C0 3634 #define C1 21173 |