1/*
2 * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische
3 * Universitaet Berlin.  See the accompanying file "COPYRIGHT" for
4 * details.  THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
5 */
6
7/* $Header: /tmp_amd/presto/export/kbs/jutta/src/gsm/RCS/code.c,v 1.3 1996/07/02 09:59:05 jutta Exp $ */
8
9#include	"config.h"
10
11
12#ifdef	HAS_STDLIB_H
13#include	<stdlib.h>
14#else
15#	include "proto.h"
16	extern char	* memcpy P((char *, char *, int));
17#endif
18
19#include	"private.h"
20#include	"gsm.h"
21#include	"proto.h"
22
23/*
24 *  4.2 FIXED POINT IMPLEMENTATION OF THE RPE-LTP CODER
25 */
26
27void Gsm_Coder P8((S,s,LARc,Nc,bc,Mc,xmaxc,xMc),
28
29	struct gsm_state	* S,
30
31	word	* s,	/* [0..159] samples		  	IN	*/
32
33/*
34 * The RPE-LTD coder works on a frame by frame basis.  The length of
35 * the frame is equal to 160 samples.  Some computations are done
36 * once per frame to produce at the output of the coder the
37 * LARc[1..8] parameters which are the coded LAR coefficients and
38 * also to realize the inverse filtering operation for the entire
39 * frame (160 samples of signal d[0..159]).  These parts produce at
40 * the output of the coder:
41 */
42
43	word	* LARc,	/* [0..7] LAR coefficients		OUT	*/
44
45/*
46 * Procedure 4.2.11 to 4.2.18 are to be executed four times per
47 * frame.  That means once for each sub-segment RPE-LTP analysis of
48 * 40 samples.  These parts produce at the output of the coder:
49 */
50
51	word	* Nc,	/* [0..3] LTP lag			OUT 	*/
52	word	* bc,	/* [0..3] coded LTP gain		OUT 	*/
53	word	* Mc,	/* [0..3] RPE grid selection		OUT     */
54	word	* xmaxc,/* [0..3] Coded maximum amplitude	OUT	*/
55	word	* xMc	/* [13*4] normalized RPE samples	OUT	*/
56)
57{
58	int	k;
59	word	* dp  = S->dp0 + 120;	/* [ -120...-1 ] */
60	word	* dpp = dp;		/* [ 0...39 ]	 */
61
62	word	so[160];
63
64	Gsm_Preprocess			(S, s, so);
65	Gsm_LPC_Analysis		(S, so, LARc);
66	Gsm_Short_Term_Analysis_Filter	(S, LARc, so);
67
68	for (k = 0; k <= 3; k++, xMc += 13) {
69
70		Gsm_Long_Term_Predictor	( S,
71					 so+k*40, /* d      [0..39] IN	*/
72					 dp,	  /* dp  [-120..-1] IN	*/
73					S->e + 5, /* e      [0..39] OUT	*/
74					dpp,	  /* dpp    [0..39] OUT */
75					 Nc++,
76					 bc++);
77
78		Gsm_RPE_Encoding	( S,
79					S->e + 5,/* e	  ][0..39][ IN/OUT */
80					  xmaxc++, Mc++, xMc );
81		/*
82		 * Gsm_Update_of_reconstructed_short_time_residual_signal
83		 *			( dpp, S->e + 5, dp );
84		 */
85
86		{ register int i;
87		  register longword ltmp;
88		  for (i = 0; i <= 39; i++)
89			dp[ i ] = GSM_ADD( S->e[5 + i], dpp[i] );
90		}
91		dp  += 40;
92		dpp += 40;
93
94	}
95	(void)memcpy( (char *)S->dp0, (char *)(S->dp0 + 160),
96		120 * sizeof(*S->dp0) );
97}
98