Commit 52aa3015 authored by Mans Rullgard's avatar Mans Rullgard
Browse files

g723.1: simplify and fix multiplication overflow



In 16-bit arithmetic, x * 0xffffc is simply x * -4 with extra overflows,
(and the constant was probably meant to be 0xfffc).  Combined with the
shift, this simplifies to -x >> 1.  Finally, clearing the low two bits
with a 32-bit mask and switching to a 32-bit type allows more efficient
code on 32-bit machines.
Signed-off-by: default avatarMans Rullgard <mans@mansr.com>
parent e141cf2c
......@@ -956,7 +956,7 @@ static void formant_postfilter(G723_1_Context *p, int16_t *lpc, int16_t *buf)
signal_ptr = filter_signal + LPC_ORDER;
for (i = 0; i < SUBFRAMES; i++) {
int16_t temp_vector[SUBFRAME_LEN];
int16_t temp;
int temp;
int auto_corr[2];
int scale, energy;
......@@ -975,7 +975,7 @@ static void formant_postfilter(G723_1_Context *p, int16_t *lpc, int16_t *buf)
temp = (auto_corr[0] >> 2) / temp;
}
p->reflection_coef = (3 * p->reflection_coef + temp + 2) >> 2;
temp = (p->reflection_coef * 0xffffc >> 3) & 0xfffc;
temp = -p->reflection_coef >> 1 & ~3;
/* Compensation filter */
for (j = 0; j < SUBFRAME_LEN; j++) {
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment