--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtwamr/q_gain_c.c	Mon May 06 03:18:47 2024 +0000
@@ -0,0 +1,151 @@
+/*
+********************************************************************************
+*
+*      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             : q_gain_c.c
+*      Purpose          : Scalar quantization of the innovative
+*                       : codebook gain.
+*
+********************************************************************************
+*/
+ 
+/*
+********************************************************************************
+*                         MODULE INCLUDE FILE AND VERSION ID
+********************************************************************************
+*/
+#include "namespace.h"
+#include "q_gain_c.h"
+ 
+/*
+********************************************************************************
+*                         INCLUDE FILES
+********************************************************************************
+*/
+#include "tw_amr.h"
+#include "typedef.h"
+#include "basic_op.h"
+#include "oper_32b.h"
+#include "no_count.h"
+#include "log2.h"
+#include "pow2.h"
+#include "gains_tab.h"
+
+/*
+********************************************************************************
+*                         PUBLIC PROGRAM CODE
+********************************************************************************
+*/
+ 
+/*--------------------------------------------------------------------------*
+ * Function q_gain_code()                                                   *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                                  *
+ * Scalar quantization of the innovative codebook gain.                     *
+ *                                                                          *
+ *--------------------------------------------------------------------------*/
+Word16 q_gain_code (        /* o  : quantization index,            Q0  */
+    enum Mode mode,         /* i  : AMR mode                           */
+    Word16 exp_gcode0,      /* i  : predicted CB gain (exponent),  Q0  */
+    Word16 frac_gcode0,     /* i  : predicted CB gain (fraction),  Q15 */
+    Word16 *gain,           /* i/o: quantized fixed codebook gain, Q1  */
+    Word16 *qua_ener_MR122, /* o  : quantized energy error,        Q10 */
+                            /*      (for MR122 MA predictor update)    */
+    Word16 *qua_ener        /* o  : quantized energy error,        Q10 */
+                            /*      (for other MA predictor update)    */
+)
+{
+    const Word16 *p;
+    Word16 i, index;
+    Word16 gcode0, err, err_min;
+    Word16 g_q0;
+
+    test ();
+    g_q0 = 0;    move16 ();
+    test ();
+    if (sub(mode, MR122) == 0)
+    {
+       g_q0 = shr (*gain, 1); /* Q1 -> Q0 */
+    }
+
+    /*-------------------------------------------------------------------*
+     *  predicted codebook gain                                          *
+     *  ~~~~~~~~~~~~~~~~~~~~~~~                                          *
+     *  gc0     = Pow2(int(d)+frac(d))                                   *
+     *          = 2^exp + 2^frac                                         *
+     *                                                                   *
+     *-------------------------------------------------------------------*/
+
+    gcode0 = extract_l (Pow2 (exp_gcode0, frac_gcode0));  /* predicted gain */
+
+    test ();
+    if (sub(mode, MR122) == 0)
+    {
+       gcode0 = shl (gcode0, 4);
+    }
+    else
+    {
+       gcode0 = shl (gcode0, 5);
+    }
+    
+    /*-------------------------------------------------------------------*
+     *                   Search for best quantizer                        *
+     *-------------------------------------------------------------------*/
+
+    p = &qua_gain_code[0]; move16 ();
+    test ();
+    if (sub(mode, MR122) == 0)
+    {
+       err_min = abs_s (sub (g_q0, mult (gcode0, *p++)));
+    }
+    else
+    {
+       err_min = abs_s (sub (*gain, mult (gcode0, *p++)));
+    }
+    p += 2;                                  /* skip quantized energy errors */
+    index = 0;              move16 (); 
+
+    for (i = 1; i < NB_QUA_CODE; i++)
+    {
+       test ();
+       if (sub(mode, MR122) == 0)
+       {
+          err = abs_s (sub (g_q0,  mult (gcode0, *p++)));
+       }
+       else
+       {
+          err = abs_s (sub (*gain, mult (gcode0, *p++)));
+       }
+       
+       p += 2;                              /* skip quantized energy error */
+
+       test (); 
+       if (sub (err, err_min) < 0)
+       {
+          err_min = err;                  move16 (); 
+          index = i;                      move16 (); 
+       }
+    }
+
+    p = &qua_gain_code[add (add (index,index), index)]; move16 ();
+    test ();
+    if (sub(mode, MR122) == 0)
+    {
+       *gain = shl (mult (gcode0, *p++), 1); 
+    }
+    else
+    {
+       *gain = mult (gcode0, *p++);
+    }
+                                            move16 ();
+    
+    /* quantized error energies (for MA predictor update) */
+    *qua_ener_MR122 = *p++;                 move16 (); 
+    *qua_ener = *p;                         move16 (); 
+
+    return index;
+}