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-rw-r--r--sysdeps/libm-ieee754/e_atanhf.c58
1 files changed, 58 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/e_atanhf.c b/sysdeps/libm-ieee754/e_atanhf.c
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+/* e_atanhf.c -- float version of e_atanh.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.
+ * ====================================================
+ */
+
+#if defined(LIBM_SCCS) && !defined(lint)
+static char rcsid[] = "$NetBSD: e_atanhf.c,v 1.4 1995/05/10 20:44:56 jtc Exp $";
+#endif
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const float one = 1.0, huge = 1e30;
+#else
+static float one = 1.0, huge = 1e30;
+#endif
+
+#ifdef __STDC__
+static const float zero = 0.0;
+#else
+static float zero = 0.0;
+#endif
+
+#ifdef __STDC__
+	float __ieee754_atanhf(float x)
+#else
+	float __ieee754_atanhf(x)
+	float x;
+#endif
+{
+	float t;
+	int32_t hx,ix;
+	GET_FLOAT_WORD(hx,x);
+	ix = hx&0x7fffffff;
+	if (ix>0x3f800000) 		/* |x|>1 */
+	    return (x-x)/(x-x);
+	if(ix==0x3f800000) 
+	    return x/zero;
+	if(ix<0x31800000&&(huge+x)>zero) return x;	/* x<2**-28 */
+	SET_FLOAT_WORD(x,ix);
+	if(ix<0x3f000000) {		/* x < 0.5 */
+	    t = x+x;
+	    t = (float)0.5*__log1pf(t+t*x/(one-x));
+	} else 
+	    t = (float)0.5*__log1pf((x+x)/(one-x));
+	if(hx>=0) return t; else return -t;
+}