[Opus] Update to v1.2.1

third_party/opus/src/silk/LPC_inv_pred_gain.c

Index: third_party/opus/src/silk/LPC_inv_pred_gain.c
diff --git a/third_party/opus/src/silk/LPC_inv_pred_gain.c b/third_party/opus/src/silk/LPC_inv_pred_gain.c
index 4af89aa5fad324799620e64c3fa22e3ea6bd9400..a3746a6ef9f3187468ccd6944837d8c02bbadd18 100644
--- a/third_party/opus/src/silk/LPC_inv_pred_gain.c
+++ b/third_party/opus/src/silk/LPC_inv_pred_gain.c
@@ -30,6 +30,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #endif
 
 #include "SigProc_FIX.h"
+#include "define.h"
 
 #define QA                          24
 #define A_LIMIT                     SILK_FIX_CONST( 0.99975, QA )
@@ -38,117 +39,103 @@ POSSIBILITY OF SUCH DAMAGE.
 
 /* Compute inverse of LPC prediction gain, and                          */
 /* test if LPC coefficients are stable (all poles within unit circle)   */
-static opus_int32 LPC_inverse_pred_gain_QA(                 /* O   Returns inverse prediction gain in energy domain, Q30    */
-    opus_int32           A_QA[ 2 ][ SILK_MAX_ORDER_LPC ],   /* I   Prediction coefficients                                  */
+static opus_int32 LPC_inverse_pred_gain_QA_c(               /* O   Returns inverse prediction gain in energy domain, Q30    */
+    opus_int32           A_QA[ SILK_MAX_ORDER_LPC ],        /* I   Prediction coefficients                                  */
     const opus_int       order                              /* I   Prediction order                                         */
 )
 {
     opus_int   k, n, mult2Q;
-    opus_int32 invGain_Q30, rc_Q31, rc_mult1_Q30, rc_mult2, tmp_QA;
-    opus_int32 *Aold_QA, *Anew_QA;
+    opus_int32 invGain_Q30, rc_Q31, rc_mult1_Q30, rc_mult2, tmp1, tmp2;
 
-    Anew_QA = A_QA[ order & 1 ];
-
-    invGain_Q30 = (opus_int32)1 << 30;
+    invGain_Q30 = SILK_FIX_CONST( 1, 30 );
     for( k = order - 1; k > 0; k-- ) {
         /* Check for stability */
-        if( ( Anew_QA[ k ] > A_LIMIT ) || ( Anew_QA[ k ] < -A_LIMIT ) ) {
+        if( ( A_QA[ k ] > A_LIMIT ) || ( A_QA[ k ] < -A_LIMIT ) ) {
             return 0;
         }
 
         /* Set RC equal to negated AR coef */
-        rc_Q31 = -silk_LSHIFT( Anew_QA[ k ], 31 - QA );
+        rc_Q31 = -silk_LSHIFT( A_QA[ k ], 31 - QA );
 
         /* rc_mult1_Q30 range: [ 1 : 2^30 ] */
-        rc_mult1_Q30 = ( (opus_int32)1 << 30 ) - silk_SMMUL( rc_Q31, rc_Q31 );
+        rc_mult1_Q30 = silk_SUB32( SILK_FIX_CONST( 1, 30 ), silk_SMMUL( rc_Q31, rc_Q31 ) );
         silk_assert( rc_mult1_Q30 > ( 1 << 15 ) );                   /* reduce A_LIMIT if fails */
         silk_assert( rc_mult1_Q30 <= ( 1 << 30 ) );
 
-        /* rc_mult2 range: [ 2^30 : silk_int32_MAX ] */
-        mult2Q = 32 - silk_CLZ32( silk_abs( rc_mult1_Q30 ) );
-        rc_mult2 = silk_INVERSE32_varQ( rc_mult1_Q30, mult2Q + 30 );
-
         /* Update inverse gain */
         /* invGain_Q30 range: [ 0 : 2^30 ] */
         invGain_Q30 = silk_LSHIFT( silk_SMMUL( invGain_Q30, rc_mult1_Q30 ), 2 );
         silk_assert( invGain_Q30 >= 0           );
         silk_assert( invGain_Q30 <= ( 1 << 30 ) );
+        if( invGain_Q30 < SILK_FIX_CONST( 1.0f / MAX_PREDICTION_POWER_GAIN, 30 ) ) {
+            return 0;
+        }
 
-        /* Swap pointers */
-        Aold_QA = Anew_QA;
-        Anew_QA = A_QA[ k & 1 ];
+        /* rc_mult2 range: [ 2^30 : silk_int32_MAX ] */
+        mult2Q = 32 - silk_CLZ32( silk_abs( rc_mult1_Q30 ) );
+        rc_mult2 = silk_INVERSE32_varQ( rc_mult1_Q30, mult2Q + 30 );
 
         /* Update AR coefficient */
-        for( n = 0; n < k; n++ ) {
-            tmp_QA = Aold_QA[ n ] - MUL32_FRAC_Q( Aold_QA[ k - n - 1 ], rc_Q31, 31 );
-            Anew_QA[ n ] = MUL32_FRAC_Q( tmp_QA, rc_mult2 , mult2Q );
+        for( n = 0; n < (k + 1) >> 1; n++ ) {
+            opus_int64 tmp64;
+            tmp1 = A_QA[ n ];
+            tmp2 = A_QA[ k - n - 1 ];
+            tmp64 = silk_RSHIFT_ROUND64( silk_SMULL( silk_SUB_SAT32(tmp1,
+                  MUL32_FRAC_Q( tmp2, rc_Q31, 31 ) ), rc_mult2 ), mult2Q);
+            if( tmp64 > silk_int32_MAX || tmp64 < silk_int32_MIN ) {
+               return 0;
+            }
+            A_QA[ n ] = ( opus_int32 )tmp64;
+            tmp64 = silk_RSHIFT_ROUND64( silk_SMULL( silk_SUB_SAT32(tmp2,
+                  MUL32_FRAC_Q( tmp1, rc_Q31, 31 ) ), rc_mult2), mult2Q);
+            if( tmp64 > silk_int32_MAX || tmp64 < silk_int32_MIN ) {
+               return 0;
+            }
+            A_QA[ k - n - 1 ] = ( opus_int32 )tmp64;
         }
     }
 
     /* Check for stability */
-    if( ( Anew_QA[ 0 ] > A_LIMIT ) || ( Anew_QA[ 0 ] < -A_LIMIT ) ) {
+    if( ( A_QA[ k ] > A_LIMIT ) || ( A_QA[ k ] < -A_LIMIT ) ) {
         return 0;
     }
 
     /* Set RC equal to negated AR coef */
-    rc_Q31 = -silk_LSHIFT( Anew_QA[ 0 ], 31 - QA );
+    rc_Q31 = -silk_LSHIFT( A_QA[ 0 ], 31 - QA );
 
     /* Range: [ 1 : 2^30 ] */
-    rc_mult1_Q30 = ( (opus_int32)1 << 30 ) - silk_SMMUL( rc_Q31, rc_Q31 );
+    rc_mult1_Q30 = silk_SUB32( SILK_FIX_CONST( 1, 30 ), silk_SMMUL( rc_Q31, rc_Q31 ) );
 
     /* Update inverse gain */
     /* Range: [ 0 : 2^30 ] */
     invGain_Q30 = silk_LSHIFT( silk_SMMUL( invGain_Q30, rc_mult1_Q30 ), 2 );
-    silk_assert( invGain_Q30 >= 0     );
-    silk_assert( invGain_Q30 <= 1<<30 );
+    silk_assert( invGain_Q30 >= 0           );
+    silk_assert( invGain_Q30 <= ( 1 << 30 ) );
+    if( invGain_Q30 < SILK_FIX_CONST( 1.0f / MAX_PREDICTION_POWER_GAIN, 30 ) ) {
+        return 0;
+    }
 
     return invGain_Q30;
 }
 
 /* For input in Q12 domain */
-opus_int32 silk_LPC_inverse_pred_gain(              /* O   Returns inverse prediction gain in energy domain, Q30        */
+opus_int32 silk_LPC_inverse_pred_gain_c(            /* O   Returns inverse prediction gain in energy domain, Q30        */
     const opus_int16            *A_Q12,             /* I   Prediction coefficients, Q12 [order]                         */
     const opus_int              order               /* I   Prediction order                                             */
 )
 {
     opus_int   k;
-    opus_int32 Atmp_QA[ 2 ][ SILK_MAX_ORDER_LPC ];
-    opus_int32 *Anew_QA;
+    opus_int32 Atmp_QA[ SILK_MAX_ORDER_LPC ];
     opus_int32 DC_resp = 0;
 
-    Anew_QA = Atmp_QA[ order & 1 ];
-
     /* Increase Q domain of the AR coefficients */
     for( k = 0; k < order; k++ ) {
         DC_resp += (opus_int32)A_Q12[ k ];
-        Anew_QA[ k ] = silk_LSHIFT32( (opus_int32)A_Q12[ k ], QA - 12 );
+        Atmp_QA[ k ] = silk_LSHIFT32( (opus_int32)A_Q12[ k ], QA - 12 );
     }
     /* If the DC is unstable, we don't even need to do the full calculations */
     if( DC_resp >= 4096 ) {
         return 0;
     }
-    return LPC_inverse_pred_gain_QA( Atmp_QA, order );
+    return LPC_inverse_pred_gain_QA_c( Atmp_QA, order );
 }
-
-#ifdef FIXED_POINT
-
-/* For input in Q24 domain */
-opus_int32 silk_LPC_inverse_pred_gain_Q24(          /* O    Returns inverse prediction gain in energy domain, Q30       */
-    const opus_int32            *A_Q24,             /* I    Prediction coefficients [order]                             */
-    const opus_int              order               /* I    Prediction order                                            */
-)
-{
-    opus_int   k;
-    opus_int32 Atmp_QA[ 2 ][ SILK_MAX_ORDER_LPC ];
-    opus_int32 *Anew_QA;
-
-    Anew_QA = Atmp_QA[ order & 1 ];
-
-    /* Increase Q domain of the AR coefficients */
-    for( k = 0; k < order; k++ ) {
-        Anew_QA[ k ] = silk_RSHIFT32( A_Q24[ k ], 24 - QA );
-    }
-
-    return LPC_inverse_pred_gain_QA( Atmp_QA, order );
-}
-#endif