Modify libatrac to use fixed-point arithmetic.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22298 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 14 insertions, 0 deletions

diff --git a/apps/codecs/libatrac/fixp_math.h b/apps/codecs/libatrac/fixp_math.h
new file mode 100644
index 0000000000..5bfc2c5703
--- /dev/null
+++ b/apps/codecs/libatrac/fixp_math.h
@@ -0,0 +1,14 @@
+#include <stdlib.h>
+
+/* Macros for converting between various fixed-point representations and floating point. */
+#define ONE_16 (1L << 16)
+#define fixtof64(x)       (float)((float)(x) / (float)(1 << 16))        //does not work on int64_t!
+#define ftofix32(x)       ((int32_t)((x) * (float)(1 << 16) + ((x) < 0 ? -0.5 : 0.5)))
+#define ftofix31(x)       ((int32_t)((x) * (float)(1 << 31) + ((x) < 0 ? -0.5 : 0.5)))
+#define fix31tof64(x)     (float)((float)(x) / (float)(1 << 31))
+
+/* Fixed point math routines for use in atrac3.c */
+inline int32_t fixdiv16(int32_t x, int32_t y);
+inline int32_t fixmul16(int32_t x, int32_t y);
+inline int32_t fixmul31(int32_t x, int32_t y);
+inline int32_t fastSqrt(int32_t n);