--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtwamr/weight_a.c	Mon May 06 18:52:57 2024 +0000
@@ -0,0 +1,67 @@
+/*
+********************************************************************************
+*
+*      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             : weight_a.c
+*      Purpose          : Spectral expansion of LP coefficients.  (order==10)
+*      Description      : a_exp[i] = a[i] * fac[i-1]    ,i=1,10
+*
+********************************************************************************
+*/
+/*
+********************************************************************************
+*                         MODULE INCLUDE FILE AND VERSION ID
+********************************************************************************
+*/
+#include "namespace.h"
+#include "weight_a.h"
+
+/*
+********************************************************************************
+*                         INCLUDE FILES
+********************************************************************************
+*/
+#include "typedef.h"
+#include "basic_op.h"
+#include "no_count.h"
+#include "cnst.h"
+
+/*
+********************************************************************************
+*                         LOCAL VARIABLES AND TABLES
+********************************************************************************
+*/
+/*
+*--------------------------------------*
+* Constants (defined in cnst.h         *
+*--------------------------------------*
+*  M         : LPC order               *
+*--------------------------------------*
+*/
+
+/*
+********************************************************************************
+*                         PUBLIC PROGRAM CODE
+********************************************************************************
+*/
+void Weight_Ai (
+    Word16 a[],         /* (i)     : a[M+1]  LPC coefficients   (M=10)    */
+    const Word16 fac[], /* (i)     : Spectral expansion factors.          */
+    Word16 a_exp[]      /* (o)     : Spectral expanded LPC coefficients   */
+)
+{
+    Word16 i;
+
+    a_exp[0] = a[0];                                    move16 (); 
+    for (i = 1; i <= M; i++)
+    {
+        a_exp[i] = round (L_mult (a[i], fac[i - 1]));   move16 (); 
+    }
+
+    return;
+}