+
−/*
+
−********************************************************************************
+
−*
+
−*      GSM AMR-NB speech codec   R98   Version 7.6.0   December 12, 2001
+
−*                                R99   Version 3.3.0                
+
−*                                REL-4 Version 4.1.0                
+
−*
+
−********************************************************************************
+
−*
+
−*      File             : inter_36.c
+
−*      Purpose          : Interpolating the normalized correlation
+
−*                       : with 1/3 or 1/6 resolution.
+
−*
+
−********************************************************************************
+
−*/
+
−/*
+
−********************************************************************************
+
−*                         MODULE INCLUDE FILE AND VERSION ID
+
−********************************************************************************
+
−*/
+
−#include "namespace.h"
+
−#include "inter_36.h"
+
− 
+
−/*
+
−********************************************************************************
+
−*                         INCLUDE FILES
+
−********************************************************************************
+
−*/
+
−#include "typedef.h"
+
−#include "basic_op.h"
+
−#include "no_count.h"
+
−#include "cnst.h"
+
−
+
−/*
+
−********************************************************************************
+
−*                         LOCAL VARIABLES AND TABLES
+
−********************************************************************************
+
−*/
+
−#define UP_SAMP_MAX  6
+
−
+
−#include "inter_36.tab"
+
−
+
−/*
+
−********************************************************************************
+
−*                         PUBLIC PROGRAM CODE
+
−********************************************************************************
+
−*/
+
−/*************************************************************************
+
− *
+
− *  FUNCTION:  Interpol_3or6()
+
− *
+
− *  PURPOSE:  Interpolating the normalized correlation with 1/3 or 1/6
+
− *            resolution.
+
− *
+
− *************************************************************************/
+
−Word16 Interpol_3or6 (  /* o : interpolated value                        */
+
−    Word16 *x,          /* i : input vector                              */
+
−    Word16 frac,        /* i : fraction  (-2..2 for 3*, -3..3 for 6*)    */
+
−    Word16 flag3        /* i : if set, upsampling rate = 3 (6 otherwise) */
+
−)
+
−{
+
−    Word16 i, k;
+
−    Word16 *x1, *x2;
+
−    const Word16 *c1, *c2;
+
−    Word32 s;
+
−
+
−    test();
+
−    if (flag3 != 0)
+
−    {
+
−      frac = shl (frac, 1);   /* inter_3[k] = inter_6[2*k] -> k' = 2*k */
+
−    }
+
−    
+
−    test (); 
+
−    if (frac < 0)
+
−    {
+
−        frac = add (frac, UP_SAMP_MAX);
+
−        x--;
+
−    }
+
−    
+
−    x1 = &x[0];                         move16 (); 
+
−    x2 = &x[1];                         move16 (); 
+
−    c1 = &inter_6[frac];                move16 (); 
+
−    c2 = &inter_6[sub (UP_SAMP_MAX, frac)]; move16 (); 
+
−
+
−    s = 0;                              move32 (); 
+
−    for (i = 0, k = 0; i < L_INTER_SRCH; i++, k += UP_SAMP_MAX)
+
−    {
+
−        s = L_mac (s, x1[-i], c1[k]);
+
−        s = L_mac (s, x2[i], c2[k]);
+
−    }
+
−
+
−    return round (s);
+
−}