Diff: fast_math.h

Revision:

12:a4b17bb682eb

Child:

13:791e20f1af43

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/fast_math.h	Fri Dec 21 22:06:56 2012 +0000
@@ -0,0 +1,16 @@
+#ifndef __fast_math_h
+#define __fast_math_h
+
+#define PI 3.14159265358979 // def. of PI
+#define DEG60   512     // 60deg = 512
+
+extern unsigned short  sin60[]; // sin table from 0 to 60 deg. (max precision error is 0.003%)
+// sin(th) = (float)(_sin(th/(PI/3.)*(float)DEG60+0.5))/65535.;
+extern long _sin(unsigned short);    // return( 65535*sin(th) ), th=rad*DEG60/(PI/3)=rad*(512*3)/PI (0<=rad<2*PI)
+extern long _cos(unsigned short);    // return( 65535*sin(th) ), th=rad*DEG60/(PI/3)=rad*(512*3)/PI (0<=rad<2*PI)
+extern void init_fast_math();       // call before using _sin(). sin0-sin60deg; 0deg=0, 60deg=512
+
+//extern float  norm(float);          // ２ノルムを計算
+extern float  sqrt2(float x);         // √xのx=1まわりのテイラー展開 √x = 1 + 1/2*(x-1) -1/4*(x-1)^2 + ...
+
+#endif
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