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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 : P_PARITY.C 
*/ 
#include "typedef.h" 
#include "ld8k.h" 
 
/*-----------------------------------------------------* 
* parity_pitch - compute parity bit for first 6 MSBs  * 
*-----------------------------------------------------*/ 
 
int parity_pitch(     /* output: parity bit (XOR of 6 MSB bits)     */ 
    int pitch_index     /* input : index for which parity is computed */ 
) 
{ 
    int temp, sum, i, bit; 
 
    temp = pitch_index >> 1; 
 
    sum = 1; 
    for (i = 0; i <= 5; i++) { 
        temp >>= 1; 
        bit = temp & 1; 
        sum = sum + bit; 
    } 
    sum = sum & 1; 
    return (sum); 
} 
 
/*--------------------------------------------------------------------* 
* check_parity_pitch - check parity of index with transmitted parity * 
*--------------------------------------------------------------------*/ 
 
int check_parity_pitch(  /* output: 0 = no error, 1= error */ 
    int pitch_index,       /* input : index of parameter     */ 
    int parity             /* input : parity bit             */ 
) 
{ 
    int temp, sum, i, bit; 
    temp = pitch_index >> 1; 
 
    sum = 1; 
    for (i = 0; i <= 5; i++) { 
        temp >>= 1; 
        bit = temp & 1; 
        sum = sum + bit; 
    } 
    sum += parity; 
    sum = sum & 1; 
    return (sum); 
}