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| author | Michael Sevakis <jethead71@rockbox.org> | 2012-04-26 15:21:43 -0400 |
|---|---|---|
| committer | Michael Sevakis <jethead71@rockbox.org> | 2012-04-26 16:04:43 -0400 |
| commit | e5c3327cefb4e6f3a9089ad30fd12bb8f40a0658 (patch) | |
| tree | 973027f2688c478bf0d30ce1ead0bfc24dae766b | |
| parent | 2866063c3cff10814f0e2e6c5263c7ee6d4c7fa1 (diff) | |
| download | rockbox-e5c3327cefb4e6f3a9089ad30fd12bb8f40a0658.zip rockbox-e5c3327cefb4e6f3a9089ad30fd12bb8f40a0658.tar.gz rockbox-e5c3327cefb4e6f3a9089ad30fd12bb8f40a0658.tar.bz2 rockbox-e5c3327cefb4e6f3a9089ad30fd12bb8f40a0658.tar.xz | |
Add a more correct absolute difference function to dsp-util.
Differences between signed samples cover the entire unsigned 32-bit
range. "abs" will think any difference exceeding INT32_MAX is negative
which is not corrent. Test which argument is greater and subtract the
lesser from it, outputting unsigned difference.
Change-Id: I73a8e5e418d49ff73d1a7c98eeb4731946dcfe84
| -rw-r--r-- | firmware/export/dsp-util.h | 13 | ||||
| -rw-r--r-- | lib/rbcodec/dsp/tdspeed.c | 7 |
2 files changed, 13 insertions, 7 deletions
diff --git a/firmware/export/dsp-util.h b/firmware/export/dsp-util.h index 76962b5..b86b2b7 100644 --- a/firmware/export/dsp-util.h +++ b/firmware/export/dsp-util.h @@ -18,8 +18,8 @@ * KIND, either express or implied. * ****************************************************************************/ -#ifndef DSP_HELPER_H -#define DSP_HELPER_H +#ifndef DSP_UTIL_H +#define DSP_UTIL_H /** Clip sample to signed 16 bit range **/ @@ -48,4 +48,11 @@ static FORCE_INLINE int32_t clip_sample_16(int32_t sample) #undef CLIP_SAMPLE_16_DEFINED -#endif /* DSP_HELPER_H */ +/* Absolute difference of signed 32-bit numbers which must be dealt with + * in the unsigned 32-bit range */ +static FORCE_INLINE uint32_t ad_s32(int32_t a, int32_t b) +{ + return (a >= b) ? (a - b) : (b - a); +} + +#endif /* DSP_UTIL_H */ diff --git a/lib/rbcodec/dsp/tdspeed.c b/lib/rbcodec/dsp/tdspeed.c index 731be12..c2f4a3f 100644 --- a/lib/rbcodec/dsp/tdspeed.c +++ b/lib/rbcodec/dsp/tdspeed.c @@ -29,6 +29,7 @@ #include "system.h" #include "tdspeed.h" #include "settings.h" +#include "dsp-util.h" #define assert(cond) @@ -308,8 +309,7 @@ static int tdspeed_apply(int32_t *buf_out[2], int32_t *buf_in[2], for (int j = 0; j < st->dst_step; j += INC2, curr += INC2, prev += INC2) { - int32_t diff = *curr - *prev; - delta += abs(diff); + delta += ad_s32(*curr, *prev); if (delta >= min_delta) goto skip; @@ -322,8 +322,7 @@ static int tdspeed_apply(int32_t *buf_out[2], int32_t *buf_in[2], for (int j = 0; j < st->dst_step; j += INC2, curr += INC2, prev += INC2) { - int32_t diff = *curr - *prev; - delta += abs(diff); + delta += ad_s32(*curr, *prev); if (delta >= min_delta) goto skip; |