commit 8c7bb4c9c7e2cb529a58e5dcdd8ce324081347c9
author Timothy Terriberry <tterribe@motherfishIV.xiph.org> Sat Oct 31 10:19:06 2009 -0700
committer Jean-Marc Valin <jean-marc.valin@usherbrooke.ca> Sat Oct 31 13:35:40 2009 -0400
tree aa345c31fc61f2c853c5c48407cfbc69a499269f
parent 630ee44aaabbf1b8a0f16ca10d5cd481dc15b4e0

Expose the normalized range for reciprocal square roots in fixed-point mode. This allows subsequnt calculations to use the full precision of the result.

libcelt/vq.c

diff --git a/libcelt/vq.c b/libcelt/vq.c
index a39858c..e75d55e 100644
--- a/libcelt/vq.c
+++ b/libcelt/vq.c
@@ -103,13 +103,21 @@
 static void normalise_residual(int * restrict iy, celt_norm * restrict X, int N, int K, celt_word32 Ryy)
 {
    int i;
-   celt_word32 g;
+#ifdef FIXED_POINT
+   int k;
+#endif
+   celt_word32 t;
+   celt_word16 g;
 
-   g = celt_rsqrt(Ryy);
+#ifdef FIXED_POINT
+   k = celt_ilog2(Ryy)>>1;
+#endif
+   t = VSHR32(Ryy, (k-7)<<1);
+   g = celt_rsqrt_norm(t);
 
    i=0;
    do
-      X[i] = EXTRACT16(SHR32(MULT16_16(g, iy[i]),1));
+      X[i] = EXTRACT16(PSHR32(MULT16_16(g, iy[i]), k+1));
    while (++i < N);
 }