g729a_bits.c

DSP上优化的G.729A代码

#include "../Common/typedef.h"
#include "../Include/G729A_ld8a.h"
#include "../Include/G729A_tab_ld8a.h"

static Word16 G729Abin2int1 ( Word16 *bitstream, Word16 no_of_bits );
static Word16 G729Abin2int2 ( Word16 *bitstream1 ,Word16 *bitstream2, Word16 no_of_bits, Word16 valuelong);
static void G729Aint2bin(Word16 value, Word16 no_of_bits, Word16 *bitstream);

void G729Aprm2bits_ld8k(Word16   prm[], Word16 bits[])
{
   Word16 i;
   *bits++ = G729A_SYNC_WORD;     
   *bits++ = G729A_SIZE_WORD;     

   for (i = 0; i < G729A_PRM_SIZE; i++)
   {
        G729Aint2bin(prm[i], G729A_bitsno[i], bits);
        bits += G729A_bitsno[i];
   }

   return;
}

static void G729Aint2bin(Word16 value, Word16 no_of_bits, Word16 *bitstream)
{
   Word16 *pt_bitstream;
   Word16   i, bit;

   pt_bitstream = bitstream + no_of_bits;

   for (i = 0; i < no_of_bits; i++)
   {
     bit = value & (Word16)0x0001;      
     if (bit == 0)
         *--pt_bitstream = G729A_BIT_0;
     else
         *--pt_bitstream = G729A_BIT_1;
     value >>= 1;
   }
}

void G729Abits2prm_ld8k(Word16 bits[], Word16   prm[])
{   
    Word16 i;
    Word16 bitslong;
    Word16 temp;
    
    bitslong = 16;
    temp = * bits;

    prm[0] = 1;
    for (i = 0; i < G729A_PRM_SIZE; i++) 
	{
		if ( G729A_bitsno [ i ] > bitslong )
		{
			prm [ i + 1 ] = G729Abin2int2 ( &temp, bits + 1, G729A_bitsno [ i ], bitslong );
			bits ++;
			bitslong = 16 + bitslong - G729A_bitsno [ i ];
		}
		else
		{
			prm [ i + 1 ] = G729Abin2int1 ( &temp, G729A_bitsno [ i ] );
			bitslong = bitslong - G729A_bitsno [ i ];
		}
	}
}

static Word16 G729Abin2int1 ( Word16 *bitstream, Word16 no_of_bits )
{
	Word32 temp;
	temp = *bitstream;
	temp = temp & 0x0000ffff;
	temp = temp << no_of_bits;
	*bitstream = (Word16) ( temp );
	return (Word16) (temp >> 16); 
}

static Word16 G729Abin2int2 ( Word16 *bitstream1 ,Word16 *bitstream2, Word16 no_of_bits, Word16 valuelong)
{
	Word32 temp1, temp2;
	temp1 = *bitstream1 & 0x0000ffff;
	temp2 = *bitstream2 & 0x0000ffff;
	temp1 = temp1 << no_of_bits;
	temp2 = temp2 << ( no_of_bits - valuelong );
	temp1 = temp1 | temp2;
	*bitstream1 = (Word16) ( temp1 );
	return (Word16) (temp1 >> 16);
}