lag_wind.c

来自「君正早期ucos系统(只有早期的才不没有打包成库),MPLAYER,文件系统,图」· C语言 代码 · 共 101 行

/*
********************************************************************************
*
*      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             : lag_wind.c
*      Purpose          : Lag windowing of autocorrelations.
*
********************************************************************************
*/
/*
********************************************************************************
*                         MODULE INCLUDE FILE AND VERSION ID
********************************************************************************
*/
#include "lag_wind.h"
const char lag_wind_id[] = "@(#)$Id $" lag_wind_h;
 
/*
********************************************************************************
*                         INCLUDE FILES
********************************************************************************
*/
#include "typedef.h"
#include "basic_op.h"
#include "oper_32b.h"
#include "count.h"
 
/*
********************************************************************************
*                         LOCAL VARIABLES AND TABLES
********************************************************************************
*/
#include "lag_wind.tab"     /* Table for Lag_Window() */
#ifdef JZ4740_MXU_OPT
#include "jzmedia.h"
#include "fixed_op.h"
#endif
 
/*
********************************************************************************
*                         PUBLIC PROGRAM CODE
********************************************************************************
*/
/*************************************************************************
 *
 *  FUNCTION:  Lag_window()
 *
 *  PURPOSE:  Lag windowing of autocorrelations.
 *
 *  DESCRIPTION:
 *         r[i] = r[i]*lag_wind[i],   i=1,...,10
 *
 *     r[i] and lag_wind[i] are in special double precision format.
 *     See "oper_32b.c" for the format.
 *
 *************************************************************************/
void Lag_window (
    Word16 m,           /* (i)     : LPC order                        */
    Word16 r_h[],       /* (i/o)   : Autocorrelations  (msb)          */
    Word16 r_l[]        /* (i/o)   : Autocorrelations  (lsb)          */
)
{
    Word16 i;
    Word32 x;

#ifdef JZ4740_MXU_OPT
    union {
         Word32 r32;
         Word16 r16[2];
     } r_temp;
    union {Word32 lag32;
           Word16 lag16[2];
     }lag_temp;
    for (i = 1; i <= m; i++)
    {
        r_temp.r16[0] = r_l[i];
        r_temp.r16[1] = r_h[i];
        lag_temp.lag16[0] = lag_l[i - 1];
        lag_temp.lag16[1] = lag_h[i - 1];
        
        x = INSN_MULT(r_temp.r32, lag_temp.lag32);
        if( x & 16384)
           x += 16384;
        r_h[i] = (Word16) (x >> 15); 
        r_l[i] = (Word16) (x - r_h[i] * 32768);
    }
#else
    for (i = 1; i <= m; i++)
    {
        x = Mpy_32 (r_h[i], r_l[i], lag_h[i - 1], lag_l[i - 1]);
        L_Extract (x, &r_h[i], &r_l[i]);
    }
#endif
    return;
}