diff libgsmefr/d1035pf.c @ 53:49dd1ac8e75b

libgsmefr: import most *.c files from ETSI source
author Mychaela Falconia <falcon@freecalypso.org>
date Fri, 25 Nov 2022 16:18:21 +0000
parents
children d273a77d5523
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libgsmefr/d1035pf.c	Fri Nov 25 16:18:21 2022 +0000
@@ -0,0 +1,76 @@
+/*************************************************************************
+ *
+ *  FUNCTION:   dec_10i40_35bits()
+ *
+ *  PURPOSE:  Builds the innovative codevector from the received
+ *            index of algebraic codebook.
+ *
+ *   See  c1035pf.c  for more details about the algebraic codebook structure.
+ *
+ *************************************************************************/
+
+#include "typedef.h"
+#include "basic_op.h"
+#include "count.h"
+
+#define L_CODE    40            /* codevector length */
+#define NB_PULSE  10            /* number of pulses  */
+#define NB_TRACK  5             /* number of track */
+
+void dec_10i40_35bits (
+    Word16 index[],    /* (i)     : index of 10 pulses (sign+position)       */
+    Word16 cod[]       /* (o)     : algebraic (fixed) codebook excitation    */
+)
+{
+    static const Word16 dgray[8] = {0, 1, 3, 2, 5, 6, 4, 7};
+    Word16 i, j, pos1, pos2, sign, tmp;
+
+    for (i = 0; i < L_CODE; i++)
+    {
+        cod[i] = 0;                                     move16 (); 
+    }
+
+    /* decode the positions and signs of pulses and build the codeword */
+
+    for (j = 0; j < NB_TRACK; j++)
+    {
+        /* compute index i */
+
+        tmp = index[j];                                 move16 ();
+        i = tmp & 7;                                    logic16 (); 
+        i = dgray[i];                                   move16 (); 
+
+        i = extract_l (L_shr (L_mult (i, 5), 1));
+        pos1 = add (i, j); /* position of pulse "j" */
+
+        i = shr (tmp, 3) & 1;                           logic16 (); 
+        test (); 
+        if (i == 0)
+        {
+            sign = 4096;                                move16 (); /* +1.0 */
+        }
+        else
+        {
+            sign = -4096;                               move16 (); /* -1.0 */
+        }
+
+        cod[pos1] = sign;                               move16 (); 
+
+        /* compute index i */
+
+        i = index[add (j, 5)] & 7;                      logic16 (); 
+        i = dgray[i];                                   move16 (); 
+        i = extract_l (L_shr (L_mult (i, 5), 1));
+
+        pos2 = add (i, j);      /* position of pulse "j+5" */
+
+        test (); 
+        if (sub (pos2, pos1) < 0)
+        {
+            sign = negate (sign);
+        }
+        cod[pos2] = add (cod[pos2], sign);              move16 (); 
+    }
+
+    return;
+}