g729ev_g729_p_parity.c

来自「最新的ITU-T的宽带语音编解码标准G.729.1,是对原先的G.729的最好的」· C语言 代码 · 共 72 行

/* ITU-T G.729EV Optimization/Characterization Candidate                         */
/* Version:       1.0.a                                                          */
/* Revision Date: June 28, 2006                                                  */

/*
   ITU-T G.729EV Optimization/Characterization Candidate    ANSI-C Source Code
   Copyright (c) 2006 
   France Telecom, Matsushita Electric, Mindspeed, Siemens AG, ETRI, VoiceAge Corp.
   All rights reserved
*/

/*------------------------------------------------------*
 * G729EV_G729_Parity_pitch - compute parity bit for first 6 MSBs   *
 *------------------------------------------------------*/

#include "stl.h"
#include "G729EV_G729_ld8k.h"


Word16 G729EV_G729_Parity_Pitch(  /* output: parity bit (XOR of 6 MSB bits)    */
                                 Word16 pitch_index /* input : index for which parity to compute */
    )
{
  Word16    temp, sum, i, bit;

  temp = shr(pitch_index, 1);

  sum = 1;
#ifdef WMOPS
  move16();
#endif
  FOR(i = 0; i <= 5; i++)
  {
    temp = shr(temp, 1);
    bit = s_and(temp, (Word16) 1);
    sum = add(sum, bit);
  }
  sum = s_and(sum, (Word16) 1);


  return sum;
}

/*--------------------------------------------------------------------*
 * G729EV_G729_check_parity_pitch - check parity of index with transmitted parity *
 *--------------------------------------------------------------------*/

Word16 G729EV_G729_Check_Parity_Pitch(                      /* output: 0 = no error, 1= error */
                                       Word16 pitch_index,  /* input : index of parameter     */
                                       Word16 parity        /* input : parity bit             */
    )
{
  Word16    temp, sum, i, bit;

  temp = shr(pitch_index, 1);

  sum = 1;
#ifdef WMOPS
  move16();
#endif
  FOR(i = 0; i <= 5; i++)
  {
    temp = shr(temp, 1);
    bit = s_and(temp, (Word16) 1);
    sum = add(sum, bit);
  }
  sum = add(sum, parity);
  sum = s_and(sum, (Word16) 1);

  return sum;
}