ref: 677e7cebedd3ac9340ab37535a17ac705c3ffc30
dir: /amr-wb/g_pitch.c/
/*-------------------------------------------------------------------*
* G_PITCH.C *
*-------------------------------------------------------------------*
* Compute the gain of pitch. Result in Q12 *
* if (gain < 0) gain =0 *
* if (gain > 1.2) gain =1.2 *
*-------------------------------------------------------------------*/
#include "typedef.h"
#include "basic_op.h"
#include "math_op.h"
#include "count.h"
Word16 G_pitch( /* (o) Q14 : Gain of pitch lag saturated to 1.2 */
Word16 xn[], /* (i) : Pitch target. */
Word16 y1[], /* (i) : filtered adaptive codebook. */
Word16 g_coeff[], /* : Correlations need for gain quantization. */
Word16 L_subfr /* : Length of subframe. */
)
{
Word16 i;
Word16 xy, yy, exp_xy, exp_yy, gain;
/* Compute scalar product <y1[],y1[]> */
yy = extract_h(Dot_product12(y1, y1, L_subfr, &exp_yy));
/* Compute scalar product <xn[],y1[]> */
xy = extract_h(Dot_product12(xn, y1, L_subfr, &exp_xy));
g_coeff[0] = yy; move16();
g_coeff[1] = exp_yy; move16();
g_coeff[2] = xy; move16();
g_coeff[3] = exp_xy; move16();
/* If (xy < 0) gain = 0 */
test();
if (xy < 0)
return ((Word16) 0);
/* compute gain = xy/yy */
xy = shr(xy, 1); /* Be sure xy < yy */
gain = div_s(xy, yy);
i = add(exp_xy, 1 - 1); /* -1 -> gain in Q14 */
i = sub(i, exp_yy);
gain = shl(gain, i); /* saturation can occur here */
/* if (gain > 1.2) gain = 1.2 in Q14 */
test();
if (sub(gain, 19661) > 0)
{
gain = 19661; move16();
}
return (gain);
}