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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_sqrtf.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_sqrtf.c')
-rw-r--r--sysdeps/libm-ieee754/e_sqrtf.c97
1 files changed, 97 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/e_sqrtf.c b/sysdeps/libm-ieee754/e_sqrtf.c
new file mode 100644
index 0000000000..7648ef4bca
--- /dev/null
+++ b/sysdeps/libm-ieee754/e_sqrtf.c
@@ -0,0 +1,97 @@
+/* e_sqrtf.c -- float version of e_sqrt.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_sqrtf.c,v 1.4 1995/05/10 20:46:19 jtc Exp $";
+#endif
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static	const float	one	= 1.0, tiny=1.0e-30;
+#else
+static	float	one	= 1.0, tiny=1.0e-30;
+#endif
+
+#ifdef __STDC__
+	float __ieee754_sqrtf(float x)
+#else
+	float __ieee754_sqrtf(x)
+	float x;
+#endif
+{
+	float z;
+	int32_t sign = (int)0x80000000; 
+	int32_t ix,s,q,m,t,i;
+	u_int32_t r;
+
+	GET_FLOAT_WORD(ix,x);
+
+    /* take care of Inf and NaN */
+	if((ix&0x7f800000)==0x7f800000) {			
+	    return x*x+x;		/* sqrt(NaN)=NaN, sqrt(+inf)=+inf
+					   sqrt(-inf)=sNaN */
+	} 
+    /* take care of zero */
+	if(ix<=0) {
+	    if((ix&(~sign))==0) return x;/* sqrt(+-0) = +-0 */
+	    else if(ix<0)
+		return (x-x)/(x-x);		/* sqrt(-ve) = sNaN */
+	}
+    /* normalize x */
+	m = (ix>>23);
+	if(m==0) {				/* subnormal x */
+	    for(i=0;(ix&0x00800000)==0;i++) ix<<=1;
+	    m -= i-1;
+	}
+	m -= 127;	/* unbias exponent */
+	ix = (ix&0x007fffff)|0x00800000;
+	if(m&1)	/* odd m, double x to make it even */
+	    ix += ix;
+	m >>= 1;	/* m = [m/2] */
+
+    /* generate sqrt(x) bit by bit */
+	ix += ix;
+	q = s = 0;		/* q = sqrt(x) */
+	r = 0x01000000;		/* r = moving bit from right to left */
+
+	while(r!=0) {
+	    t = s+r; 
+	    if(t<=ix) { 
+		s    = t+r; 
+		ix  -= t; 
+		q   += r; 
+	    } 
+	    ix += ix;
+	    r>>=1;
+	}
+
+    /* use floating add to find out rounding direction */
+	if(ix!=0) {
+	    z = one-tiny; /* trigger inexact flag */
+	    if (z>=one) {
+	        z = one+tiny;
+		if (z>one)
+		    q += 2;
+		else
+		    q += (q&1);
+	    }
+	}
+	ix = (q>>1)+0x3f000000;
+	ix += (m <<23);
+	SET_FLOAT_WORD(z,ix);
+	return z;
+}