/*
 * This C source file has been adapted from TU-Berlin libgsm source
 * (src/decode.c), original notice follows:
 *
 * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische
 * Universitaet Berlin.  See the accompanying file "COPYRIGHT" for
 * details.  THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
 */

#include <stdint.h>
#include "tw_gsmfr.h"
#include "typedef.h"
#include "ed_state.h"
#include "ed_internal.h"

/*
 *  4.3 FIXED POINT IMPLEMENTATION OF THE RPE-LTP DECODER
 */

static void Postprocessing (
	struct gsmfr_0610_state	* S,
	register word 		* s)
{
	register int		k;
	register word		msr = S->msr;
	register longword	ltmp;	/* for GSM_ADD */
	register word		tmp;

	for (k = 160; k--; s++) {
		tmp = GSM_MULT_R( msr, 28180 );
		msr = GSM_ADD(*s, tmp);  	   /* Deemphasis 	     */
		*s  = GSM_ADD(msr, msr) & 0xFFF8;  /* Truncation & Upscaling */
	}
	S->msr = msr;
}

void gsmfr_0610_decode_params(struct gsmfr_0610_state *S,
			      const struct gsmfr_param_frame *inp, int16_t *s)
{
	int		j, k;
	word		erp[40], wt[160];
	word		* drp = S->dp0 + 120;

	for (j=0; j <= 3; j++) {
		Gsm_RPE_Decoding(S, inp->xmaxc[j], inp->Mc[j], inp->xMc[j],
				 erp);
		Gsm_Long_Term_Synthesis_Filtering(S, inp->Nc[j], inp->bc[j],
						  erp, drp);

		for (k = 0; k <= 39; k++) wt[ j * 40 + k ] =  drp[ k ];
	}

	Gsm_Short_Term_Synthesis_Filter(S, inp->LARc, wt, s);
	Postprocessing(S, s);
}