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Abramo Bagnara <abramo@alsa-project.org>

Browse source 
Thu, 09 Dec 1999 09:56:47 +0100
Rate plugin is now ready for optimizations (I've verified reading asm
generated that loop unrolling is not fully satisfactory, I'll try
another solution later today).
This commit is contained in:
Jaroslav Kysela 1999-12-09 09:21:56 +00:00
parent 4ec59e7283
commit 15c2b15ba1
1 changed files with 27 additions and 23 deletions
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50
src/pcm/plugin/rate.c
View file

@ -56,38 +56,42 @@ static void mix(struct rate_private_data *data, int voices,
{
unsigned int pos;
signed int val;
signed short *S1, *S2;
signed short S1, S2;
int voice;
signed short *src, *dst;
int size;
pos = data->pos;
S1 = data->last_S1;
S2 = data->last_S2;
if (pos >> SHIFT) {
src_ptr += ((pos >> SHIFT) - 1) * voices; pos &= MASK;
for (voice = 0; voice < voices; ++voice) {
S1[voice] = S2[voice];
S2[voice] = src_ptr[voice];
}
}
while (dst_size-- > 0) {
for (voice = 0; voice < voices; ++voice) {
pos = data->pos;
S1 = data->last_S1[voice];
S2 = data->last_S2[voice];
src = src_ptr + voice;
dst = dst_ptr + voice;
size = dst_size;
if (pos >> SHIFT) {
src_ptr += (pos >> SHIFT) * voices; pos &= MASK;
for (voice = 0; voice < voices; ++voice) {
S1[voice] = S2[voice];
S2[voice] = src_ptr[voice];
}
src += ((pos >> SHIFT) - 1) * voices;
pos &= MASK;
S1 = S2;
S2 = *src;
}
for (voice = 0; voice < voices; ++voice) {
val = S1[voice] + ((S2[voice] - S1[voice]) * (signed int)pos) / BITS;
while (size-- > 0) {
if (pos >> SHIFT) {
src += (pos >> SHIFT) * voices;
pos &= MASK;
S1 = S2;
S2 = *src;
}
val = S1 + ((S2 - S1) * (signed int)pos) / BITS;
if (val < -32768)
val = -32768;
else if (val > 32767)
val = 32767;
*dst_ptr++ = val;
*dst = val;
dst += voices;
pos += data->pitch;
}
pos += data->pitch;
data->last_S1[voice] = S1;
data->last_S2[voice] = S2;
}
data->pos = pos;
}