--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/dec_12k2.c	Wed Apr 03 05:31:37 2024 +0000
@@ -0,0 +1,424 @@
+/***************************************************************************
+ *
+ *  FILE NAME:    dec_12k2.c
+ *
+ *  FUNCTIONS DEFINED IN THIS FILE:
+ *                   Init_Decoder_12k2   and  Decoder_12k2
+ *
+ *
+ *  Init_Decoder_12k2():
+ *      Initialization of variables for the decoder section.
+ *
+ *  Decoder_12k2():
+ *      Speech decoder routine operating on a frame basis.
+ *
+ ***************************************************************************/
+
+#include "typedef.h"
+#include "basic_op.h"
+#include "sig_proc.h"
+#include "count.h"
+#include "codec.h"
+#include "cnst.h"
+
+#include "dtx.h"
+
+extern Word16 dtx_mode;
+
+/*---------------------------------------------------------------*
+ *   Decoder constant parameters (defined in "cnst.h")           *
+ *---------------------------------------------------------------*
+ *   L_FRAME     : Frame size.                                   *
+ *   L_FRAME_BY2 : Half the frame size.                          *
+ *   L_SUBFR     : Sub-frame size.                               *
+ *   M           : LPC order.                                    *
+ *   MP1         : LPC order+1                                   *
+ *   PIT_MIN     : Minimum pitch lag.                            *
+ *   PIT_MAX     : Maximum pitch lag.                            *
+ *   L_INTERPOL  : Length of filter for interpolation            *
+ *   PRM_SIZE    : size of vector containing analysis parameters *
+ *---------------------------------------------------------------*/
+
+/*--------------------------------------------------------*
+ *         Static memory allocation.                      *
+ *--------------------------------------------------------*/
+
+ /* Excitation vector */
+
+static Word16 old_exc[L_FRAME + PIT_MAX + L_INTERPOL];
+static Word16 *exc;
+
+ /* Lsp (Line spectral pairs) */
+
+static Word16 lsp_old[M];
+
+ /* Filter's memory */
+
+static Word16 mem_syn[M];
+
+ /* Memories for bad frame handling */
+
+static Word16 prev_bf;
+static Word16 state;
+
+/***************************************************************************
+ *
+ *   FUNCTION:  Init_Decoder_12k2
+ *
+ *   PURPOSE: Initialization of variables for the decoder section.
+ *
+ ***************************************************************************/
+
+void Init_Decoder_12k2 (void)
+{
+    /* Initialize static pointer */
+
+    exc = old_exc + PIT_MAX + L_INTERPOL;
+
+    /* Static vectors to zero */
+
+    Set_zero (old_exc, PIT_MAX + L_INTERPOL);
+    Set_zero (mem_syn, M);
+
+    /* Initialize lsp_old [] */
+
+    lsp_old[0] = 30000;
+    lsp_old[1] = 26000;
+    lsp_old[2] = 21000;
+    lsp_old[3] = 15000;
+    lsp_old[4] = 8000;
+    lsp_old[5] = 0;
+    lsp_old[6] = -8000;
+    lsp_old[7] = -15000;
+    lsp_old[8] = -21000;
+    lsp_old[9] = -26000;
+
+    /* Initialize memories of bad frame handling */
+
+    prev_bf = 0;
+    state = 0;
+
+    return;
+}
+
+/***************************************************************************
+ *
+ *   FUNCTION:  Decoder_12k2
+ *
+ *   PURPOSE:   Speech decoder routine.
+ *
+ ***************************************************************************/
+
+void Decoder_12k2 (
+    Word16 parm[], /* input : vector of synthesis parameters
+                      parm[0] = bad frame indicator (bfi)       */
+    Word16 synth[],/* output: synthesis speech                  */
+    Word16 A_t[],  /* output: decoded LP filter in 4 subframes  */
+    Word16 TAF,
+    Word16 SID_flag
+)
+{
+
+    /* LPC coefficients */
+
+    Word16 *Az;                 /* Pointer on A_t */
+
+    /* LSPs */
+
+    Word16 lsp_new[M];
+    Word16 lsp_mid[M];
+
+    /* Algebraic codevector */
+
+    Word16 code[L_SUBFR];
+
+    /* excitation */
+
+    Word16 excp[L_SUBFR];
+
+    /* Scalars */
+
+    Word16 i, i_subfr;
+    Word16 T0, T0_frac, index;
+    Word16 gain_pit, gain_code, bfi, pit_sharp;
+    Word16 temp;
+    Word32 L_temp;
+
+    extern Word16 rxdtx_ctrl, rx_dtx_state;
+    extern Word32 L_pn_seed_rx;
+
+    /* Test bad frame indicator (bfi) */
+
+    bfi = *parm++;              move16 (); 
+
+    /* Set state machine */
+
+    test (); test (); 
+    if (bfi != 0)
+    {
+        state = add (state, 1);
+    }
+    else if (sub (state, 6) == 0)
+    {
+        state = 5;
+    }
+    else
+    {
+        state = 0;
+    }
+
+    test (); 
+    if (sub (state, 6) > 0)
+    {
+        state = 6;
+    }
+    rx_dtx (&rxdtx_ctrl, TAF, bfi, SID_flag);
+
+    /* If this frame is the first speech frame after CNI period,     */
+    /* set the BFH state machine to an appropriate state depending   */
+    /* on whether there was DTX muting before start of speech or not */
+    /* If there was DTX muting, the first speech frame is muted.     */
+    /* If there was no DTX muting, the first speech frame is not     */
+    /* muted. The BFH state machine starts from state 5, however, to */
+    /* keep the audible noise resulting from a SID frame which is    */
+    /* erroneously interpreted as a good speech frame as small as    */
+    /* possible (the decoder output in this case is quickly muted)   */
+    test (); logic16 ();
+    if ((rxdtx_ctrl & RX_FIRST_SP_FLAG) != 0)
+    {
+        test (); logic16 ();
+        if ((rxdtx_ctrl & RX_PREV_DTX_MUTING) != 0)
+        {
+            state = 5;    move16 ();
+            prev_bf = 1;  move16 ();
+        }
+        else
+        {
+            state = 5;    move16 ();
+            prev_bf = 0;  move16 ();
+        }
+    }
+
+#if (WMOPS)
+    fwc ();                     /* function worst case */
+
+    /* Note! The following test is performed only for determining
+       whether or not DTX mode is active, in order to switch off
+       worst worst case complexity printout when DTX mode is active
+    */
+    if ((rxdtx_ctrl & RX_SP_FLAG) == 0)
+    {
+        dtx_mode = 1;
+    }
+#endif
+
+    D_plsf_5 (parm, lsp_mid, lsp_new, bfi, rxdtx_ctrl, rx_dtx_state);
+
+#if (WMOPS)
+    fwc ();                     /* function worst case */
+#endif
+    /* Advance synthesis parameters pointer */
+    parm += 5;                  move16 (); 
+
+    test (); logic16 (); 
+    if ((rxdtx_ctrl & RX_SP_FLAG) != 0)
+    {
+        /* Interpolation of LPC for the 4 subframes */
+
+        Int_lpc (lsp_old, lsp_mid, lsp_new, A_t);
+    }
+    else
+    {
+        /* Comfort noise: use the same parameters in each subframe */
+        Lsp_Az (lsp_new, A_t);
+
+        for (i = 0; i < MP1; i++)
+        {
+            A_t[i + MP1] = A_t[i];      move16 (); 
+            A_t[i + 2 * MP1] = A_t[i];  move16 (); 
+            A_t[i + 3 * MP1] = A_t[i];  move16 (); 
+        }
+    }
+
+    /* update the LSPs for the next frame */
+    for (i = 0; i < M; i++)
+    {
+        lsp_old[i] = lsp_new[i];        move16 (); 
+    }
+#if (WMOPS)
+    fwc ();                     /* function worst case */
+#endif
+
+    /*---------------------------------------------------------------------*
+     *       Loop for every subframe in the analysis frame                 *
+     *---------------------------------------------------------------------*
+     * The subframe size is L_SUBFR and the loop is repeated               *
+     * L_FRAME/L_SUBFR times                                               *
+     *     - decode the pitch delay                                        *
+     *     - decode algebraic code                                         *
+     *     - decode pitch and codebook gains                               *
+     *     - find the excitation and compute synthesis speech              *
+     *---------------------------------------------------------------------*/
+
+    /* pointer to interpolated LPC parameters */
+    Az = A_t;                           move16 (); 
+
+    for (i_subfr = 0; i_subfr < L_FRAME; i_subfr += L_SUBFR)
+    {
+
+        index = *parm++;                move16 (); /* pitch index */
+
+        test (); logic16 (); 
+        if ((rxdtx_ctrl & RX_SP_FLAG) != 0)
+        {
+            T0 = Dec_lag6 (index, PIT_MIN, PIT_MAX, i_subfr, L_FRAME_BY2,
+                           &T0_frac, bfi);
+#if (WMOPS)
+            fwc ();             /* function worst case */
+#endif
+
+            /*-------------------------------------------------*
+             * - Find the adaptive codebook vector.            *
+             *-------------------------------------------------*/
+
+            Pred_lt_6 (&exc[i_subfr], T0, T0_frac, L_SUBFR);
+#if (WMOPS)
+            fwc ();             /* function worst case */
+#endif
+        }
+        else
+        {
+            T0 = L_SUBFR;               move16 (); 
+        }
+
+        /*-------------------------------------------------------*
+         * - Decode pitch gain.                                  *
+         *-------------------------------------------------------*/
+
+        index = *parm++;                move16 (); 
+
+        gain_pit = d_gain_pitch (index, bfi, state, prev_bf, rxdtx_ctrl);
+        move16 (); 
+#if (WMOPS)
+        fwc ();                 /* function worst case */
+#endif
+
+        /*-------------------------------------------------------*
+         * - Decode innovative codebook.                         *
+         *-------------------------------------------------------*/
+
+        test (); logic16 (); 
+        if ((rxdtx_ctrl & RX_SP_FLAG) != 0)
+        {
+            dec_10i40_35bits (parm, code);
+        }
+        else
+        {   /* Use pseudo noise for excitation when SP_flag == 0 */
+            build_CN_code (code, &L_pn_seed_rx);
+        }
+
+        parm += 10;                     move16 (); 
+#if (WMOPS)
+        fwc ();                 /* function worst case */
+#endif
+
+        /*-------------------------------------------------------*
+         * - Add the pitch contribution to code[].               *
+         *-------------------------------------------------------*/
+
+        /* pit_sharp = gain_pit;                   */
+        /* if (pit_sharp > 1.0) pit_sharp = 1.0;   */
+
+        pit_sharp = shl (gain_pit, 3);
+
+        /* This loop is not entered when SP_FLAG is 0 */
+        for (i = T0; i < L_SUBFR; i++)
+        {
+            temp = mult (code[i - T0], pit_sharp);
+            code[i] = add (code[i], temp);
+                                        move16 (); 
+        }
+#if (WMOPS)
+        fwc ();                 /* function worst case */
+#endif
+        /* post processing of excitation elements */
+
+        test (); /* This test is not passed when SP_FLAG is 0 */
+        if (sub (pit_sharp, 16384) > 0)
+        {
+            for (i = 0; i < L_SUBFR; i++)
+            {
+                temp = mult (exc[i + i_subfr], pit_sharp);
+                L_temp = L_mult (temp, gain_pit);
+                L_temp = L_shl (L_temp, 1);
+                excp[i] = round (L_temp);
+                                        move16 (); 
+            }
+        }
+        /*-------------------------------------------------*
+         * - Decode codebook gain.                         *
+         *-------------------------------------------------*/
+
+        index = *parm++;                move16 (); /* index of energy VQ */
+
+        d_gain_code (index, code, L_SUBFR, &gain_code, bfi, state, prev_bf,
+                     rxdtx_ctrl, i_subfr, rx_dtx_state);
+#if (WMOPS)
+        fwc ();                 /* function worst case */
+#endif
+
+        /*-------------------------------------------------------*
+         * - Find the total excitation.                          *
+         * - Find synthesis speech corresponding to exc[].       *
+         *-------------------------------------------------------*/
+        for (i = 0; i < L_SUBFR; i++)
+        {
+            /* exc[i] = gain_pit*exc[i] + gain_code*code[i]; */
+
+            L_temp = L_mult (exc[i + i_subfr], gain_pit);
+            L_temp = L_mac (L_temp, code[i], gain_code);
+            L_temp = L_shl (L_temp, 3);
+
+            exc[i + i_subfr] = round (L_temp);
+                                        move16 (); 
+        }
+#if (WMOPS)
+        fwc ();                 /* function worst case */
+#endif
+
+        test (); 
+        if (sub (pit_sharp, 16384) > 0)
+        {
+            for (i = 0; i < L_SUBFR; i++)
+            {
+                excp[i] = add (excp[i], exc[i + i_subfr]);
+                                        move16 (); 
+            }
+            agc2 (&exc[i_subfr], excp, L_SUBFR);
+            Syn_filt (Az, excp, &synth[i_subfr], L_SUBFR, mem_syn, 1);
+        }
+        else
+        {
+            Syn_filt (Az, &exc[i_subfr], &synth[i_subfr], L_SUBFR, mem_syn, 1);
+        }
+
+#if (WMOPS)
+        fwc ();                 /* function worst case */
+#endif
+        /* interpolated LPC parameters for next subframe */
+        Az += MP1;                      move16 (); 
+    }
+
+    /*--------------------------------------------------*
+     * Update signal for next frame.                    *
+     * -> shift to the left by L_FRAME  exc[]           *
+     *--------------------------------------------------*/
+
+    Copy (&old_exc[L_FRAME], &old_exc[0], PIT_MAX + L_INTERPOL);
+#if (WMOPS)
+    fwc ();                     /* function worst case */
+#endif
+    prev_bf = bfi;                      move16 (); 
+
+    return;
+}