1 files changed, 100 insertions, 0 deletions
diff --git a/gr-vocoder/lib/gsm/code.c b/gr-vocoder/lib/gsm/code.c
new file mode 100644
index 000000000..19af507b7
--- /dev/null
+++ b/gr-vocoder/lib/gsm/code.c
@@ -0,0 +1,100 @@
+/*
+ * 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.
+ */
+
+/* $Header$ */
+
+#include	"config.h"
+
+
+#ifdef	HAS_STDLIB_H
+#include	<stdlib.h>
+#else
+#	include "proto.h"
+	extern char	* memcpy P((char *, char *, int));
+#endif
+
+#include	"private.h"
+#include	"gsm.h"
+#include	"proto.h"
+#include <string.h>
+
+/* 
+ *  4.2 FIXED POINT IMPLEMENTATION OF THE RPE-LTP CODER 
+ */
+
+void Gsm_Coder P8((S,s,LARc,Nc,bc,Mc,xmaxc,xMc),
+
+	struct gsm_state	* S,
+
+	word	* s,	/* [0..159] samples		  	IN	*/
+
+/*
+ * The RPE-LTD coder works on a frame by frame basis.  The length of
+ * the frame is equal to 160 samples.  Some computations are done
+ * once per frame to produce at the output of the coder the
+ * LARc[1..8] parameters which are the coded LAR coefficients and 
+ * also to realize the inverse filtering operation for the entire
+ * frame (160 samples of signal d[0..159]).  These parts produce at
+ * the output of the coder:
+ */
+
+	word	* LARc,	/* [0..7] LAR coefficients		OUT	*/
+
+/*
+ * Procedure 4.2.11 to 4.2.18 are to be executed four times per
+ * frame.  That means once for each sub-segment RPE-LTP analysis of
+ * 40 samples.  These parts produce at the output of the coder:
+ */
+
+	word	* Nc,	/* [0..3] LTP lag			OUT 	*/
+	word	* bc,	/* [0..3] coded LTP gain		OUT 	*/
+	word	* Mc,	/* [0..3] RPE grid selection		OUT     */
+	word	* xmaxc,/* [0..3] Coded maximum amplitude	OUT	*/
+	word	* xMc	/* [13*4] normalized RPE samples	OUT	*/
+)
+{
+	int	k;
+	word	* dp  = S->dp0 + 120;	/* [ -120...-1 ] */
+	word	* dpp = dp;		/* [ 0...39 ]	 */
+
+	static word e[50];
+
+	word	so[160];
+
+	Gsm_Preprocess			(S, s, so);
+	Gsm_LPC_Analysis		(S, so, LARc);
+	Gsm_Short_Term_Analysis_Filter	(S, LARc, so);
+
+	for (k = 0; k <= 3; k++, xMc += 13) {
+
+		Gsm_Long_Term_Predictor	( S,
+					 so+k*40, /* d      [0..39] IN	*/
+					 dp,	  /* dp  [-120..-1] IN	*/
+					e + 5,	  /* e      [0..39] OUT	*/
+					dpp,	  /* dpp    [0..39] OUT */
+					 Nc++,
+					 bc++);
+
+		Gsm_RPE_Encoding	( S,
+					e + 5,	/* e	  ][0..39][ IN/OUT */
+					  xmaxc++, Mc++, xMc );
+		/*
+		 * Gsm_Update_of_reconstructed_short_time_residual_signal
+		 *			( dpp, e + 5, dp );
+		 */
+
+		{ register int i;
+		  register longword ltmp;
+		  for (i = 0; i <= 39; i++)
+			dp[ i ] = GSM_ADD( e[5 + i], dpp[i] );
+		}
+		dp  += 40;
+		dpp += 40;
+
+	}
+	(void)memcpy( (char *)S->dp0, (char *)(S->dp0 + 160),
+		120 * sizeof(*S->dp0) );
+}