[Opus] Update to v1.2.1

third_party/opus/src/silk/float/LPC_inv_pred_gain_FLP.c

 /***********************************************************************
 Copyright (c) 2006-2011, Skype Limited. All rights reserved.
 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:
 - Redistributions of source code must retain the above copyright notice,
 this list of conditions and the following disclaimer.
 - Redistributions in binary form must reproduce the above copyright
 notice, this list of conditions and the following disclaimer in the
 documentation and/or other materials provided with the distribution.
@@ skipping 13 matching lines @@
 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 POSSIBILITY OF SUCH DAMAGE.
 ***********************************************************************/
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
 #include "SigProc_FIX.h"
 #include "SigProc_FLP.h"
-
-#define RC_THRESHOLD        0.9999f
+#include "define.h"
 
 /* compute inverse of LPC prediction gain, and                          */
 /* test if LPC coefficients are stable (all poles within unit circle)   */
 /* this code is based on silk_a2k_FLP()                                 */
 silk_float silk_LPC_inverse_pred_gain_FLP(  /* O    return inverse prediction gain, energy domain               */
     const silk_float    *A,                 /* I    prediction coefficients [order]                             */
     opus_int32          order               /* I    prediction order                                            */
 )
 {
     opus_int   k, n;
-    double     invGain, rc, rc_mult1, rc_mult2;
-    silk_float Atmp[ 2 ][ SILK_MAX_ORDER_LPC ];
-    silk_float *Aold, *Anew;
+    double     invGain, rc, rc_mult1, rc_mult2, tmp1, tmp2;
+    silk_float Atmp[ SILK_MAX_ORDER_LPC ];
 
-    Anew = Atmp[ order & 1 ];
-    silk_memcpy( Anew, A, order * sizeof(silk_float) );
+    silk_memcpy( Atmp, A, order * sizeof(silk_float) );
 
     invGain = 1.0;
     for( k = order - 1; k > 0; k-- ) {
-        rc = -Anew[ k ];
-        if( rc > RC_THRESHOLD || rc < -RC_THRESHOLD ) {
+        rc = -Atmp[ k ];
+        rc_mult1 = 1.0f - rc * rc;
+        invGain *= rc_mult1;
+        if( invGain * MAX_PREDICTION_POWER_GAIN < 1.0f ) {
             return 0.0f;
         }
-        rc_mult1 = 1.0f - rc * rc;
         rc_mult2 = 1.0f / rc_mult1;
-        invGain *= rc_mult1;
-        /* swap pointers */
-        Aold = Anew;
-        Anew = Atmp[ k & 1 ];
-        for( n = 0; n < k; n++ ) {
-            Anew[ n ] = (silk_float)( ( Aold[ n ] - Aold[ k - n - 1 ] * rc ) * rc_mult2 );
+        for( n = 0; n < (k + 1) >> 1; n++ ) {
+            tmp1 = Atmp[ n ];
+            tmp2 = Atmp[ k - n - 1 ];
+            Atmp[ n ]         = (silk_float)( ( tmp1 - tmp2 * rc ) * rc_mult2 );
+            Atmp[ k - n - 1 ] = (silk_float)( ( tmp2 - tmp1 * rc ) * rc_mult2 );
         }
     }
-    rc = -Anew[ 0 ];
-    if( rc > RC_THRESHOLD || rc < -RC_THRESHOLD ) {
+    rc = -Atmp[ 0 ];
+    rc_mult1 = 1.0f - rc * rc;
+    invGain *= rc_mult1;
+    if( invGain * MAX_PREDICTION_POWER_GAIN < 1.0f ) {
         return 0.0f;
     }
-    rc_mult1 = 1.0f - rc * rc;
-    invGain *= rc_mult1;
     return (silk_float)invGain;
 }