Implements fixed-point silk_LPC_analysis_filter() in terms of celt_fir()

Saves 2.5% on ARM without any asm. The float build still uses the old
code because celt_fir() then becomes a float function.

1 files changed, 22 insertions, 1 deletions

diff --git a/silk/LPC_analysis_filter.c b/silk/LPC_analysis_filter.c
index e2c0c88b..9bfeba0f 100644
--- a/silk/LPC_analysis_filter.c
+++ b/silk/LPC_analysis_filter.c
@@ -30,6 +30,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #endif
 
 #include "SigProc_FIX.h"
+#include "celt_lpc.h"
 
 /*******************************************/
 /* LPC analysis filter                     */
@@ -46,14 +47,33 @@ void silk_LPC_analysis_filter(
     const opus_int32            d                   /* I    Filter order                                                */
 )
 {
-    opus_int         ix, j;
+    opus_int   j;
+#ifdef FIXED_POINT
+    opus_int16 mem[SILK_MAX_ORDER_LPC];
+    opus_int16 num[SILK_MAX_ORDER_LPC];
+#else
+    int ix;
     opus_int32       out32_Q12, out32;
     const opus_int16 *in_ptr;
+#endif
 
     silk_assert( d >= 6 );
     silk_assert( (d & 1) == 0 );
     silk_assert( d <= len );
 
+#ifdef FIXED_POINT
+    silk_assert( d <= SILK_MAX_ORDER_LPC );
+    for ( j = 0; j < d; j++ ) {
+        num[ j ] = -B[ j ];
+    }
+    for (j=0;j<d;j++) {
+        mem[ j ] = in[ d - j - 1 ];
+    }
+    celt_fir( in + d, num, out + d, len - d, d, mem );
+    for ( j = 0; j < d; j++ ) {
+        out[ j ] = 0;
+    }
+#else
     for( ix = d; ix < len; ix++ ) {
         in_ptr = &in[ ix - 1 ];
 
@@ -82,4 +102,5 @@ void silk_LPC_analysis_filter(
 
     /* Set first d output samples to zero */
     silk_memset( out, 0, d * sizeof( opus_int16 ) );
+#endif
 }