about summary refs log tree commit diff
path: root/sysdeps/libm-ieee754/s_frexp.c
diff options
context:
space:
mode:
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/s_frexp.c
parent1521668f2afae1dc2ef5d7ffaeb84353b36874dd (diff)
downloadglibc-f7eac6eb504f4baf13dbb4d26717942df050ebe6.tar.gz
glibc-f7eac6eb504f4baf13dbb4d26717942df050ebe6.tar.xz
glibc-f7eac6eb504f4baf13dbb4d26717942df050ebe6.zip
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/s_frexp.c')
-rw-r--r--sysdeps/libm-ieee754/s_frexp.c60
1 files changed, 60 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/s_frexp.c b/sysdeps/libm-ieee754/s_frexp.c
new file mode 100644
index 0000000000..1f3bfcef5b
--- /dev/null
+++ b/sysdeps/libm-ieee754/s_frexp.c
@@ -0,0 +1,60 @@
+/* @(#)s_frexp.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: s_frexp.c,v 1.9 1995/05/10 20:47:24 jtc Exp $";
+#endif
+
+/*
+ * for non-zero x 
+ *	x = frexp(arg,&exp);
+ * return a double fp quantity x such that 0.5 <= |x| <1.0
+ * and the corresponding binary exponent "exp". That is
+ *	arg = x*2^exp.
+ * If arg is inf, 0.0, or NaN, then frexp(arg,&exp) returns arg 
+ * with *exp=0. 
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const double
+#else
+static double
+#endif
+two54 =  1.80143985094819840000e+16; /* 0x43500000, 0x00000000 */
+
+#ifdef __STDC__
+	double __frexp(double x, int *eptr)
+#else
+	double __frexp(x, eptr)
+	double x; int *eptr;
+#endif
+{
+	int32_t hx, ix, lx;
+	EXTRACT_WORDS(hx,lx,x);
+	ix = 0x7fffffff&hx;
+	*eptr = 0;
+	if(ix>=0x7ff00000||((ix|lx)==0)) return x;	/* 0,inf,nan */
+	if (ix<0x00100000) {		/* subnormal */
+	    x *= two54;
+	    GET_HIGH_WORD(hx,x);
+	    ix = hx&0x7fffffff;
+	    *eptr = -54;
+	}
+	*eptr += (ix>>20)-1022;
+	hx = (hx&0x800fffff)|0x3fe00000;
+	SET_HIGH_WORD(x,hx);
+	return x;
+}
+weak_alias (__frexp, frexp)