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authorUlrich Drepper <drepper@redhat.com>1997-04-05 01:26:47 +0000
committerUlrich Drepper <drepper@redhat.com>1997-04-05 01:26:47 +0000
commit26dee9c49cbbec8826db4c29e99fb50d9392a047 (patch)
tree98cce94e2e72bcb491b108c3c8f82192070b4b8f /sysdeps/libm-ieee754/s_cbrtf.c
parentfe7bdd630fab35270a88b0731cd0fc10de062046 (diff)
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1997-04-05 03:11  Ulrich Drepper  <drepper@cygnus.com>

	* inet/arpa/inet.h: Rewrite.  Don't use the ugly BSD way to write
	headers but instead add comments and parameter names.
	Don't use BSD specific types in prototypes.

	* manual/nss.texi: Correct a few typos and errors.

	* sysdeps/libm-ieee754/s_cbrt.c: Complete rewrite based on better
	algorithm.
	* sysdeps/libm-ieee754/s_cbrtf.c: Likewise.
	* sysdeps/libm-ieee754/s_cbrtl.c: Likewise.

	* sysdeps/libm-i387/s_cbrt.S: New file.  Optimized assembler version
	with new algorithm.
	* sysdeps/libm-i387/s_cbrtf.S: New file.
	* sysdeps/libm-i387/s_cbrtl.S: New file.

	* sysdeps/libm-i387/s_frexp.S: Optimize even more.
	* sysdeps/libm-i387/s_frexpf.S: Likewise.
	* sysdeps/libm-i387/s_frexpl.S: Likewise.

1997-04-04 18:55  Thorsten Kukuk  <kukuk@vt.uni-paderborn.de>

	* nis/Makefile: Remove CFLAGS-*, add publickey to databases.

	* nis/nis_call.c: Add MASTER_ONLY and HARD_LOOKUP flags, compile
	DES part only with secure RPC add-on.

	* nis/nis_names.c (nis_modify): Fix rpc function number.

	* nis/nis_server.c: Fix typos.

	* nis/nss_compat/compat-grp.c: Add NIS+ support.
	* nis/nss_compat/compat-pwd.c: Likewise.
	* nis/nss_compat/compat-spwd.c: Likewise.

	* nis/nss_nis/nis-grp.c: Only a return value > 0 from parse_line
	signals success.

	* nis/nss_nis/nis-publickey.c: Changes for compiling with/without
	secure RPC.
	* nis/nss_nisplus/nisplus-publickey.c: Likewise.
	* nis/ypclnt.c: Likewise.
	* nis/nis_intern.h: Likewise.

	* nis/nss_nisplus/nisplus-alias.c: Correct parser return code.
	* nis/nss_nisplus/nisplus-ethers.c: Likewise.
	* nis/nss_nisplus/nisplus-hosts.c: Likewise.
	* nis/nss_nisplus/nisplus-network.c: Likewise.
	* nis/nss_nisplus/nisplus-proto.c: Likewise.
	* nis/nss_nisplus/nisplus-pwd.c: Likewise.
	* nis/nss_nisplus/nisplus-rpc.c: Likewise.
	* nis/nss_nisplus/nisplus-service.c: Likewise.
	* nis/nss_nisplus/nisplus-spwd.c: Likewise.

	* nis/nss_nisplus/nisplus-grp.c: Rewrite parser for fixing errors
	and speedup.
	* nis/nss_nisplus/nisplus-netgrp.c: Likewise.

1997-04-04 17:03  Ulrich Drepper  <drepper@cygnus.com>

	* math/libm-test.c (cbrt_test): Add tests for +-inf and NaN
	arguments.

1997-04-03 19:24  H.J. Lu  <hjl@gnu.ai.mit.edu>

	* sysdeps/unix/sysv/linux/sigset.h (__sigisemptyset): Fix a
	typo.

1997-04-03 16:10  Andreas Jaeger  <aj@arthur.pfalz.de>

	* sysdeps/libm-ieee754/s_nanf.c:
	* sysdeps/libm-ieee754/s_nan.c:
	* sysdeps/libm-ieee754/s_nanl.c: Include <stdio.h> for
	declaration of sprintf.

1997-04-03 13:37  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/libm-ieee754/s_cexp.c: Fix type: string_alias ->
	strong_alias.
	Reported by sun <asun@zoology.washington.edu>.

	* rpc/auth.h: Removed.
	* rpc/auth_des.h: Removed.
	* sunrpc/rpc/auth.h: Moved to ...
	* sysdeps/generic/rpc/auth.h: ...here.
	* sunrpc/rpc/auth_des.h: Moved to ...
	* sysdeps/generic/rpc/auth_des.h: ...here.

1997-04-03 04:28  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/libm-i387/s_frexp.S: New file.  ix87 optimized version.
	* sysdeps/libm-i387/s_frexpf.S: New file.
	* sysdeps/libm-i387/s_frexpl.S: New file.

1997-04-01 10:11  H.J. Lu  <hjl@gnu.ai.mit.edu>

	* sysdeps/unix/sysv/linux/Makefile [$(subdir)=inet]
	(sysdep_headers): Remove netinet/icmp.h.

	Describe `inf', `infinity', `nan', `nan(...)' inputs for strtod
	* sysdeps/i386/memcmp.S: Likewise.
	* time/antarctica: Likewise.
	* time/australasia: Likewise.
Diffstat (limited to 'sysdeps/libm-ieee754/s_cbrtf.c')
-rw-r--r--sysdeps/libm-ieee754/s_cbrtf.c118
1 files changed, 48 insertions, 70 deletions
diff --git a/sysdeps/libm-ieee754/s_cbrtf.c b/sysdeps/libm-ieee754/s_cbrtf.c
index a2b3c8106c..f9f687c011 100644
--- a/sysdeps/libm-ieee754/s_cbrtf.c
+++ b/sysdeps/libm-ieee754/s_cbrtf.c
@@ -1,84 +1,62 @@
-/* s_cbrtf.c -- float version of s_cbrt.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: s_cbrtf.c,v 1.4 1995/05/10 20:46:51 jtc Exp $";
-#endif
+/* Compute cubic root of float value.
+   Copyright (C) 1997 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Dirk Alboth <dirka@uni-paderborn.de> and
+   Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
 
 #include "math.h"
 #include "math_private.h"
 
-/* cbrtf(x)
- * Return cube root of x
- */
-#ifdef __STDC__
-static const unsigned 
-#else
-static unsigned 
-#endif
-	B1 = 709958130, /* B1 = (84+2/3-0.03306235651)*2**23 */
-	B2 = 642849266; /* B2 = (76+2/3-0.03306235651)*2**23 */
 
-#ifdef __STDC__
-static const float
-#else
-static float
-#endif
-C =  5.4285717010e-01, /* 19/35     = 0x3f0af8b0 */
-D = -7.0530611277e-01, /* -864/1225 = 0xbf348ef1 */
-E =  1.4142856598e+00, /* 99/70     = 0x3fb50750 */
-F =  1.6071428061e+00, /* 45/28     = 0x3fcdb6db */
-G =  3.5714286566e-01; /* 5/14      = 0x3eb6db6e */
+#define CBRT2 1.2599210498948731648		/* 2^(1/3) */
+#define SQR_CBRT2 1.5874010519681994748		/* 2^(2/3) */
+
+static const double factor[5] =
+{
+  1.0 / SQR_CBRT2,
+  1.0 / CBRT2,
+  1.0,
+  CBRT2,
+  SQR_CBRT2
+};
+
 
-#ifdef __STDC__
-	float __cbrtf(float x) 
-#else
-	float __cbrtf(x) 
-	float x;
-#endif
+float
+__cbrtf (float x)
 {
-	float r,s,t;
-	int32_t hx;
-	u_int32_t sign;
-	u_int32_t high;
+  float xm, ym, u, t2;
+  int xe;
+
+  /* Reduce X.  XM now is an range 1.0 to 0.5.  */
+  xm = __frexpf (fabsf (x), &xe);
 
-	GET_FLOAT_WORD(hx,x);
-	sign=hx&0x80000000; 		/* sign= sign(x) */
-	hx  ^=sign;
-	if(hx>=0x7f800000) return(x+x); /* cbrt(NaN,INF) is itself */
-	if(hx==0) 
-	    return(x);		/* cbrt(0) is itself */
+  /* If X is not finite or is null return it (with raising exceptions
+     if necessary.  */
+  if (xe == 0)
+    return x + x;
 
-	SET_FLOAT_WORD(x,hx);	/* x <- |x| */
-    /* rough cbrt to 5 bits */
-	if(hx<0x00800000) 		/* subnormal number */
-	  {SET_FLOAT_WORD(t,0x4b800000); /* set t= 2**24 */
-	   t*=x; GET_FLOAT_WORD(high,t); SET_FLOAT_WORD(t,high/3+B2);
-	  }
-	else
-	  SET_FLOAT_WORD(t,hx/3+B1);
+  u = (0.492659620528969547 + (0.697570460207922770
+			       - 0.191502161678719066 * xm) * xm);
 
+  t2 = u * u * u;
 
-    /* new cbrt to 23 bits */
-	r=t*t/x;
-	s=C+r*t;
-	t*=G+F/(s+E+D/s);	
+  ym = u * (t2 + 2.0 * xm) / (2.0 * t2 + xm) * factor[2 + xe % 3];
 
-    /* retore the sign bit */
-	GET_FLOAT_WORD(high,t);
-	SET_FLOAT_WORD(t,high|sign);
-	return(t);
+  return __ldexpf (x > 0.0 ? ym : -ym, xe / 3);
 }
 weak_alias (__cbrtf, cbrtf)