glibc/sysdeps/libm-ieee754/s_cbrtf.c
Roland McGrath f7eac6eb50 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.
1996-03-05 21:41:30 +00:00

85 lines
2.0 KiB
C

/* 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
#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 */
#ifdef __STDC__
float __cbrtf(float x)
#else
float __cbrtf(x)
float x;
#endif
{
float r,s,t;
int32_t hx;
u_int32_t sign;
u_int32_t high;
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 */
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);
/* new cbrt to 23 bits */
r=t*t/x;
s=C+r*t;
t*=G+F/(s+E+D/s);
/* retore the sign bit */
GET_FLOAT_WORD(high,t);
SET_FLOAT_WORD(t,high|sign);
return(t);
}
weak_alias (__cbrtf, cbrtf)