--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtwamr/d2_9pf.c	Thu Apr 18 22:18:45 2024 +0000
@@ -0,0 +1,103 @@
+/*
+*****************************************************************************
+*
+*      GSM AMR-NB speech codec   R98   Version 7.6.0   December 12, 2001
+*                                R99   Version 3.3.0                
+*                                REL-4 Version 4.1.0                
+*
+*****************************************************************************
+*
+*      File             : d2_9pf.c
+*      Purpose          : Algebraic codebook decoder
+*
+*****************************************************************************
+*/
+
+/*
+*****************************************************************************
+*                         MODULE INCLUDE FILE AND VERSION ID
+*****************************************************************************
+*/
+#include "namespace.h"
+#include "d2_9pf.h"
+ 
+/*
+*****************************************************************************
+*                         INCLUDE FILES
+*****************************************************************************
+*/
+#include "typedef.h"
+#include "basic_op.h"
+#include "no_count.h"
+#include "cnst.h"
+
+/*
+********************************************************************************
+*                         LOCAL VARIABLES AND TABLES
+********************************************************************************
+*/
+#define NB_PULSE 2           /* number of pulses */
+ 
+#include "c2_9pf.tab"
+
+/*
+********************************************************************************
+*                         PUBLIC PROGRAM CODE
+********************************************************************************
+*/
+/*************************************************************************
+ *
+ *  FUNCTION:  decode_2i40_9bits (decod_ACELP())
+ *
+ *  PURPOSE:   Algebraic codebook decoder. For details about the encoding se
+ *             c2_9pf.c
+ *
+ *************************************************************************/
+
+void decode_2i40_9bits(
+    Word16 subNr,  /* i : subframe number                          */
+    Word16 sign,   /* i : signs of 2 pulses.                       */
+    Word16 index,  /* i : Positions of the 2 pulses.               */
+    Word16 cod[]   /* o : algebraic (fixed) codebook excitation    */
+)
+{
+    Word16 i, j, k;
+    Word16 pos[NB_PULSE];
+
+    /* Decode the positions */
+    /* table bit  is the MSB */ 
+    j = shr((index & 64),6);                                 logic16 ();
+
+    i = index & 7;                                       logic16 ();
+
+    i = add(i, shl(i, 2));       /* pos0 =i*5+startPos[j*8+subNr*2] */
+    k = startPos[add(shl(j, 3), shl(subNr, 1))];
+    pos[0] = add(i, k);                                  move16 ();    
+
+    index = shr(index, 3);
+    i = index & 7;                                       logic16 ();
+
+    i = add(i, shl(i, 2));       /* pos1 =i*5+startPos[j*8+subNr*2+1] */
+    k = startPos[add(add(shl(j, 3), shl(subNr, 1)), 1)];
+    pos[1] = add(i, k);                                  move16 ();
+
+    /* decode the signs  and build the codeword */
+
+    for (i = 0; i < L_SUBFR; i++) {
+        cod[i] = 0;                                      move16 ();
+    }
+
+    for (j = 0; j < NB_PULSE; j++) {
+        i = sign & 1;                                    logic16 ();
+        sign = shr(sign, 1);
+
+        test ();
+        if (i != 0) {
+            cod[pos[j]] = 8191;                          move16 (); /* +1.0 */
+        } else {
+            cod[pos[j]] = -8192;                         move16 (); /* -1.0 */
+        }
+    }
+
+    return;
+}