fixed-point: PLC auto-correlation converted
diff --git a/libcelt/plc.c b/libcelt/plc.c
index 334da8f..6a06ac9 100644
--- a/libcelt/plc.c
+++ b/libcelt/plc.c
@@ -137,33 +137,37 @@
int n
)
{
- float d;
+ celt_word32 d;
int i;
- float scale=1;
- VARDECL(float, xx);
+ VARDECL(celt_word16, xx);
SAVE_STACK;
- ALLOC(xx, n, float);
+ ALLOC(xx, n, celt_word16);
for (i=0;i<n;i++)
xx[i] = x[i];
for (i=0;i<overlap;i++)
{
- xx[i] *= (1./Q15ONE)*window[i];
- xx[n-i-1] *= (1./Q15ONE)*window[i];
+ xx[i] = MULT16_16_Q15(x[i],window[i]);
+ xx[n-i-1] = MULT16_16_Q15(x[n-i-1],window[i]);
}
#ifdef FIXED_POINT
{
float ac0=0;
+ int shift;
for(i=0;i<n;i++)
- ac0 += x[i]*x[i];
- ac0+=10;
- scale = 2000000000/ac0;
+ ac0 += SHR32(MULT16_16(xx[i],xx[i]),8);
+ ac0 += 1+n;
+
+ shift = celt_ilog2(ac0)-30+8;
+ shift = (shift+1)/2;
+ for(i=0;i<n;i++)
+ xx[i] = VSHR32(xx[i], shift);
}
#endif
while (lag>=0)
{
for (i = lag, d = 0; i < n; i++)
- d += x[i] * x[i-lag];
- ac[lag] = d*scale;
+ d += xx[i] * xx[i-lag];
+ ac[lag] = d;
/*printf ("%f ", ac[lag]);*/
lag--;
}