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/* 
   ITU-T G.729 Annex C+ - Reference C code for floating point 
                         implementation of G.729 Annex C+ 
                         (integration of Annexes B, D and E) 
                          Version 2.1 of October 1999 
*/ 
 
/* 
 File : FILTERE.C 
*/ 
 
/***************************************/ 
/* General filter routines             */ 
/***************************************/ 
#include "typedef.h" 
#include "ld8k.h" 
#include "ld8cp.h" 
 
/*-----------------------------------------------------------* 
* convolve - convolve vectors x and h and put result in y   * 
*-----------------------------------------------------------*/ 
 
void convolve( 
    FLOAT x[],             /* input : input vector x[0:l]                     */ 
    FLOAT h[],             /* input : impulse response or second input h[0:l] */ 
    FLOAT y[],             /* output: x convolved with h , y[0:l]             */ 
    int  l                 /* input : dimension of all vectors                */ 
) 
{ 
    FLOAT temp; 
    int    i, n; 
     
    for (n = 0; n < l; n++) 
    { 
        temp = (F)0.0; 
        for (i = 0; i <= n; i++) 
            temp += x[i]*h[n-i]; 
        y[n] = temp; 
    } 
     
    return; 
} 
 
/*-----------------------------------------------------------* 
* syn_filt - filter with synthesis filter 1/A(z)            * 
*-----------------------------------------------------------*/ 
 
void syn_filte( 
    int m,         /* (i)    : LPC order                         */ 
    FLOAT a[],     /* input : predictor coefficients a[0:m]    */ 
    FLOAT x[],     /* input : excitation signal                */ 
    FLOAT y[],     /* output: filtered output signal           */ 
    int  l,        /* input : vector dimension                 */ 
    FLOAT mem[],   /* in/out: filter memory                    */ 
    int  update    /* input : 0 = no memory update, 1 = update */ 
) 
{ 
    int  i,j; 
     
    /* This is usually done by memory allocation (l+m) */ 
    FLOAT yy_b[L_SUBFR+M_BWD]; 
    FLOAT s, *yy, *py, *pa; 
     
    /* Copy mem[] to yy[] */ 
    yy = yy_b; 
    for (i = 0; i