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authorRich Felker <dalias@aerifal.cx>2011-02-12 00:22:29 -0500
committerRich Felker <dalias@aerifal.cx>2011-02-12 00:22:29 -0500
commit0b44a0315b47dd8eced9f3b7f31580cf14bbfc01 (patch)
tree6eaef0d8a720fa3da580de87b647fff796fe80b3 /src/math/k_cosf.c
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initial check-in, version 0.5.0 v0.5.0
Diffstat (limited to 'src/math/k_cosf.c')
-rw-r--r--src/math/k_cosf.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/src/math/k_cosf.c b/src/math/k_cosf.c
new file mode 100644
index 00000000..61dc3749
--- /dev/null
+++ b/src/math/k_cosf.c
@@ -0,0 +1,52 @@
+/* k_cosf.c -- float version of k_cos.c
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+#include <math.h>
+#include "math_private.h"
+
+static const float
+one =  1.0000000000e+00, /* 0x3f800000 */
+C1  =  4.1666667908e-02, /* 0x3d2aaaab */
+C2  = -1.3888889225e-03, /* 0xbab60b61 */
+C3  =  2.4801587642e-05, /* 0x37d00d01 */
+C4  = -2.7557314297e-07, /* 0xb493f27c */
+C5  =  2.0875723372e-09, /* 0x310f74f6 */
+C6  = -1.1359647598e-11; /* 0xad47d74e */
+
+float
+__kernel_cosf(float x, float y)
+{
+        float a,hz,z,r,qx;
+        int32_t ix;
+        GET_FLOAT_WORD(ix,x);
+        ix &= 0x7fffffff;                       /* ix = |x|'s high word*/
+        if(ix<0x32000000) {                     /* if x < 2**27 */
+            if(((int)x)==0) return one;         /* generate inexact */
+        }
+        z  = x*x;
+        r  = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6)))));
+        if(ix < 0x3e99999a)                     /* if |x| < 0.3 */
+            return one - ((float)0.5*z - (z*r - x*y));
+        else {
+            if(ix > 0x3f480000) {               /* x > 0.78125 */
+                qx = (float)0.28125;
+            } else {
+                SET_FLOAT_WORD(qx,ix-0x01000000);       /* x/4 */
+            }
+            hz = (float)0.5*z-qx;
+            a  = one-qx;
+            return a - (hz - (z*r-x*y));
+        }
+}