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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)
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initial check-in, version 0.5.0v0.5.0
Diffstat (limited to 'src/math/s_tanf.c')
-rw-r--r--src/math/s_tanf.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/src/math/s_tanf.c b/src/math/s_tanf.c
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+/* s_tanf.c -- float version of s_tan.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"
+
+float
+tanf(float x)
+{
+ float y[2],z=0.0;
+ int32_t n, ix;
+
+ GET_FLOAT_WORD(ix,x);
+
+ /* |x| ~< pi/4 */
+ ix &= 0x7fffffff;
+ if(ix <= 0x3f490fda) return __kernel_tanf(x,z,1);
+
+ /* tan(Inf or NaN) is NaN */
+ else if (ix>=0x7f800000) return x-x; /* NaN */
+
+ /* argument reduction needed */
+ else {
+ n = __ieee754_rem_pio2f(x,y);
+ return __kernel_tanf(y[0],y[1],1-((n&1)<<1)); /* 1 -- n even
+ -1 -- n odd */
+ }
+}