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/* 
   ITU-T G.729 Annex C - Reference C code for floating point 
                         implementation of G.729 
                         Version 1.01 of 15.September.98 
*/ 
 
/* 
---------------------------------------------------------------------- 
                    COPYRIGHT NOTICE 
---------------------------------------------------------------------- 
   ITU-T G.729 Annex C ANSI C source code 
   Copyright (C) 1998, AT&T, France Telecom, NTT, University of 
   Sherbrooke.  All rights reserved. 
 
---------------------------------------------------------------------- 
*/ 
 
/* 
 File : COR_FUNC.C 
*/ 
 
/* Functions corr_xy2() and cor_h_x()   */ 
 
#include "typedef.h" 
#include "ld8k.h" 
 
/*---------------------------------------------------------------------------- 
* corr_xy2 - compute the correlation products needed for gain computation 
*---------------------------------------------------------------------------- 
*/ 
void corr_xy2( 
    FLOAT xn[],            /* input : target vector x[0:l_subfr] */ 
    FLOAT y1[],            /* input : filtered adaptive codebook vector */ 
    FLOAT y2[],            /* input : filtered 1st codebook innovation */ 
    FLOAT g_coeff[]        /* output:  , -2 , and 2*/ 
) 
{ 
    FLOAT y2y2, xny2, y1y2; 
    int i; 
     
    y2y2= (F)0.01; 
    for (i = 0; i < L_SUBFR; i++) y2y2 += y2[i]*y2[i]; 
    g_coeff[2] = y2y2 ; 
     
    xny2 = (F)0.01; 
    for (i = 0; i < L_SUBFR; i++) xny2+= xn[i]*y2[i]; 
    g_coeff[3] = (F)-2.0* xny2; 
     
    y1y2 = (F)0.01; 
    for (i = 0; i < L_SUBFR; i++) y1y2 += y1[i]*y2[i]; 
    g_coeff[4] = (F)2.0* y1y2 ; 
     
    return; 
     
} 
 
/*--------------------------------------------------------------------------* 
*  Function  cor_h_x()                                                     * 
*  ~~~~~~~~~~~~~~~~~~~~                                                    * 
* Compute  correlations of input response h[] with the target vector X[].  * 
*--------------------------------------------------------------------------*/ 
 
void cor_h_x( 
    FLOAT h[],        /* (i) :Impulse response of filters      */ 
    FLOAT x[],        /* (i) :Target vector                    */ 
    FLOAT d[]         /* (o) :Correlations between h[] and x[] */ 
) 
{ 
    int i, j; 
    FLOAT  s; 
     
    for (i = 0; i < L_SUBFR; i++) 
    { 
        s = (F)0.0; 
        for (j = i; j <  L_SUBFR; j++) 
            s += x[j] * h[j-i]; 
        d[i] = s; 
    } 
     
    return; 
}