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authorRoland McGrath <roland@gnu.org>1996-03-05 21:41:30 +0000
committerRoland McGrath <roland@gnu.org>1996-03-05 21:41:30 +0000
commitf7eac6eb504f4baf13dbb4d26717942df050ebe6 (patch)
tree95ff129c06c7f6f246a5e2bfa489ba6382659d19 /sysdeps/libm-ieee754/e_acosh.c
parent1521668f2afae1dc2ef5d7ffaeb84353b36874dd (diff)
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Mon Mar 4 20:54:40 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
	* Makeconfig ($(common-objpfx)config.make): Depend on config.h.in.


Mon Mar  4 17:35:09 1996  Roland McGrath  <roland@charlie-brown.gnu.ai.mit.edu>

	* hurd/catch-signal.c (hurd_safe_memmove): New function.
	(hurd_safe_copyin, hurd_safe_copyout): New functions.
	* hurd/hurd/sigpreempt.h: Declare them.

Sun Mar  3 08:43:44 1996  Roland McGrath  <roland@charlie-brown.gnu.ai.mit.edu>

	Replace math code with fdlibm from Sun as modified for netbsd by
	JT Conklin and Ian Taylor, including x86 FPU support.
	* sysdeps/libm-ieee754, sysdeps/libm-i387: New directories.
	* math/math_private.h: New file.
	* sysdeps/i386/fpu/Implies: New file.
	* sysdeps/ieee754/Implies: New file.
	* math/machine/asm.h, math/machine/endian.h: New files.
	* math/Makefile, math/math.h: Rewritten.
	* mathcalls.h, math/mathcalls.h: New file, broken out of math.h.
	* math/finite.c: File removed.
	* sysdeps/generic/Makefile [$(subdir)=math]: Frobnication removed.

	* math/test-math.c: Include errno.h and string.h.

	* sysdeps/unix/bsd/dirstream.h: File removed.
	* sysdeps/unix/bsd/readdir.c: File removed.
Diffstat (limited to 'sysdeps/libm-ieee754/e_acosh.c')
-rw-r--r--sysdeps/libm-ieee754/e_acosh.c69
1 files changed, 69 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/e_acosh.c b/sysdeps/libm-ieee754/e_acosh.c
new file mode 100644
index 0000000000..27c29cd8c9
--- /dev/null
+++ b/sysdeps/libm-ieee754/e_acosh.c
@@ -0,0 +1,69 @@
+/* @(#)e_acosh.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * 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_acosh.c,v 1.9 1995/05/12 04:57:18 jtc Exp $";
+#endif
+
+/* __ieee754_acosh(x)
+ * Method :
+ *	Based on 
+ *		acosh(x) = log [ x + sqrt(x*x-1) ]
+ *	we have
+ *		acosh(x) := log(x)+ln2,	if x is large; else
+ *		acosh(x) := log(2x-1/(sqrt(x*x-1)+x)) if x>2; else
+ *		acosh(x) := log1p(t+sqrt(2.0*t+t*t)); where t=x-1.
+ *
+ * Special cases:
+ *	acosh(x) is NaN with signal if x<1.
+ *	acosh(NaN) is NaN without signal.
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const double 
+#else
+static double 
+#endif
+one	= 1.0,
+ln2	= 6.93147180559945286227e-01;  /* 0x3FE62E42, 0xFEFA39EF */
+
+#ifdef __STDC__
+	double __ieee754_acosh(double x)
+#else
+	double __ieee754_acosh(x)
+	double x;
+#endif
+{	
+	double t;
+	int32_t hx;
+	u_int32_t lx;
+	EXTRACT_WORDS(hx,lx,x);
+	if(hx<0x3ff00000) {		/* x < 1 */
+	    return (x-x)/(x-x);
+	} else if(hx >=0x41b00000) {	/* x > 2**28 */
+	    if(hx >=0x7ff00000) {	/* x is inf of NaN */
+	        return x+x;
+	    } else 
+		return __ieee754_log(x)+ln2;	/* acosh(huge)=log(2x) */
+	} else if(((hx-0x3ff00000)|lx)==0) {
+	    return 0.0;			/* acosh(1) = 0 */
+	} else if (hx > 0x40000000) {	/* 2**28 > x > 2 */
+	    t=x*x;
+	    return __ieee754_log(2.0*x-one/(x+__ieee754_sqrt(t-one)));
+	} else {			/* 1<x<2 */
+	    t = x-one;
+	    return __log1p(t+__sqrt(2.0*t+t*t));
+	}
+}