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Audio: Optimize division by speed of sound using fixed-point reciprocal 

This commit optimizes the division by the speed of sound in the
`theoretical_time_differences` function. By precomputing the fixed-point
reciprocal of the speed of sound, we eliminate the need for a costly
division operation in each iteration.

Additionally, a redundant 'if' statement is removed from the
'tdfb_direction_copy_emphasis' function, simplifying the code.

Signed-off-by: Shriram Shastry <malladi.sastry@intel.com>
This commit is contained in:
Shriram Shastry 2024-05-23 12:24:59 +05:30 committed by Liam Girdwood
parent 75778fc981
commit b12b69f4cc
2 changed files with 5 additions and 1 deletions
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5
src/audio/tdfb/tdfb_direction.c
View File

@ -403,8 +403,11 @@ static void theoretical_time_differences(struct tdfb_comp_data *cd, int16_t az)
for (i = 0; i < n_mic - 1; i++) {
delta_d = d[i + 1] - d[0]; /* Meters Q4.12 */
/* Multiply delta_d (Q4.12) by RECIPROCAL_SPEED_OF_SOUND_Q31 (Q1.31) and
* right-shift the result by 12 bits to preserve the Q1.31 format.
*/
cd->direction.timediff_iter[i] =
(int32_t)((((int64_t)delta_d) << 19) / SPEED_OF_SOUND);
Q_MULTS_32X32((int64_t)delta_d, RECIPROCAL_SPEED_OF_SOUND_Q31, 12, 31, 31);
}
}

1
src/include/sof/math/numbers.h
View File

@ -117,5 +117,6 @@ uint32_t crc32(uint32_t base, const void *data, uint32_t bytes);
/* Speed of sound (m/s) in 20 C temperature at standard atmospheric pressure */
#define SPEED_OF_SOUND 343
#define RECIPROCAL_SPEED_OF_SOUND_Q31 6260885 /* Q1.31 */
#endif /* __SOF_MATH_NUMBERS_H__ */