minix/lib/libm/noieee_src/n_cabs.c
Ben Gras 2fe8fb192f Full switch to clang/ELF. Drop ack. Simplify.
There is important information about booting non-ack images in
docs/UPDATING. ack/aout-format images can't be built any more, and
booting clang/ELF-format ones is a little different. Updating to the
new boot monitor is recommended.

Changes in this commit:

	. drop boot monitor -> allowing dropping ack support
	. facility to copy ELF boot files to /boot so that old boot monitor
	  can still boot fairly easily, see UPDATING
	. no more ack-format libraries -> single-case libraries
	. some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases
	. drop several ack toolchain commands, but not all support
	  commands (e.g. aal is gone but acksize is not yet).
	. a few libc files moved to netbsd libc dir
	. new /bin/date as minix date used code in libc/
	. test compile fix
	. harmonize includes
	. /usr/lib is no longer special: without ack, /usr/lib plays no
	  kind of special bootstrapping role any more and bootstrapping
	  is done exclusively through packages, so releases depend even
	  less on the state of the machine making them now.
	. rename nbsd_lib* to lib*
	. reduce mtree
2012-02-14 14:52:02 +01:00

228 lines
6.6 KiB
C

/* $NetBSD: n_cabs.c,v 1.5 2003/08/07 16:44:50 agc Exp $ */
/*
* Copyright (c) 1985, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char sccsid[] = "@(#)cabs.c 8.1 (Berkeley) 6/4/93";
#endif /* not lint */
/* HYPOT(X,Y)
* RETURN THE SQUARE ROOT OF X^2 + Y^2 WHERE Z=X+iY
* DOUBLE PRECISION (VAX D format 56 bits, IEEE DOUBLE 53 BITS)
* CODED IN C BY K.C. NG, 11/28/84;
* REVISED BY K.C. NG, 7/12/85.
*
* Required system supported functions :
* copysign(x,y)
* finite(x)
* scalb(x,N)
* sqrt(x)
*
* Method :
* 1. replace x by |x| and y by |y|, and swap x and
* y if y > x (hence x is never smaller than y).
* 2. Hypot(x,y) is computed by:
* Case I, x/y > 2
*
* y
* hypot = x + -----------------------------
* 2
* sqrt ( 1 + [x/y] ) + x/y
*
* Case II, x/y <= 2
* y
* hypot = x + --------------------------------------------------
* 2
* [x/y] - 2
* (sqrt(2)+1) + (x-y)/y + -----------------------------
* 2
* sqrt ( 1 + [x/y] ) + sqrt(2)
*
*
*
* Special cases:
* hypot(x,y) is INF if x or y is +INF or -INF; else
* hypot(x,y) is NAN if x or y is NAN.
*
* Accuracy:
* hypot(x,y) returns the sqrt(x^2+y^2) with error less than 1 ulps (units
* in the last place). See Kahan's "Interval Arithmetic Options in the
* Proposed IEEE Floating Point Arithmetic Standard", Interval Mathematics
* 1980, Edited by Karl L.E. Nickel, pp 99-128. (A faster but less accurate
* code follows in comments.) In a test run with 500,000 random arguments
* on a VAX, the maximum observed error was .959 ulps.
*
* Constants:
* The hexadecimal values are the intended ones for the following constants.
* The decimal values may be used, provided that the compiler will convert
* from decimal to binary accurately enough to produce the hexadecimal values
* shown.
*/
#define _LIBM_STATIC
#include "mathimpl.h"
vc(r2p1hi, 2.4142135623730950345E0 ,8279,411a,ef32,99fc, 2, .9A827999FCEF32)
vc(r2p1lo, 1.4349369327986523769E-17 ,597d,2484,754b,89b3, -55, .84597D89B3754B)
vc(sqrt2, 1.4142135623730950622E0 ,04f3,40b5,de65,33f9, 1, .B504F333F9DE65)
ic(r2p1hi, 2.4142135623730949234E0 , 1, 1.3504F333F9DE6)
ic(r2p1lo, 1.2537167179050217666E-16 , -53, 1.21165F626CDD5)
ic(sqrt2, 1.4142135623730951455E0 , 0, 1.6A09E667F3BCD)
#ifdef vccast
#define r2p1hi vccast(r2p1hi)
#define r2p1lo vccast(r2p1lo)
#define sqrt2 vccast(sqrt2)
#endif
double
hypot(double x, double y)
{
static const double zero=0, one=1,
small=1.0E-18; /* fl(1+small)==1 */
static const ibig=30; /* fl(1+2**(2*ibig))==1 */
double t,r;
int exp;
if(finite(x))
if(finite(y))
{
x=copysign(x,one);
y=copysign(y,one);
if(y > x)
{ t=x; x=y; y=t; }
if(x == zero) return(zero);
if(y == zero) return(x);
exp= logb(x);
if(exp-(int)logb(y) > ibig )
/* raise inexact flag and return |x| */
{ one+small; return(x); }
/* start computing sqrt(x^2 + y^2) */
r=x-y;
if(r>y) { /* x/y > 2 */
r=x/y;
r=r+sqrt(one+r*r); }
else { /* 1 <= x/y <= 2 */
r/=y; t=r*(r+2.0);
r+=t/(sqrt2+sqrt(2.0+t));
r+=r2p1lo; r+=r2p1hi; }
r=y/r;
return(x+r);
}
else if(y==y) /* y is +-INF */
return(copysign(y,one));
else
return(y); /* y is NaN and x is finite */
else if(x==x) /* x is +-INF */
return (copysign(x,one));
else if(finite(y))
return(x); /* x is NaN, y is finite */
#if !defined(__vax__)&&!defined(tahoe)
else if(y!=y) return(y); /* x and y is NaN */
#endif /* !defined(__vax__)&&!defined(tahoe) */
else return(copysign(y,one)); /* y is INF */
}
/* CABS(Z)
* RETURN THE ABSOLUTE VALUE OF THE COMPLEX NUMBER Z = X + iY
* DOUBLE PRECISION (VAX D format 56 bits, IEEE DOUBLE 53 BITS)
* CODED IN C BY K.C. NG, 11/28/84.
* REVISED BY K.C. NG, 7/12/85.
*
* Required kernel function :
* hypot(x,y)
*
* Method :
* cabs(z) = hypot(x,y) .
*/
struct complex { double x, y; };
double
cabs(z)
struct complex z;
{
return hypot(z.x,z.y);
}
double
z_abs(z)
struct complex *z;
{
return hypot(z->x,z->y);
}
/* A faster but less accurate version of cabs(x,y) */
#if 0
double hypot(x,y)
double x, y;
{
static const double zero=0, one=1;
small=1.0E-18; /* fl(1+small)==1 */
static const ibig=30; /* fl(1+2**(2*ibig))==1 */
double temp;
int exp;
if(finite(x))
if(finite(y))
{
x=copysign(x,one);
y=copysign(y,one);
if(y > x)
{ temp=x; x=y; y=temp; }
if(x == zero) return(zero);
if(y == zero) return(x);
exp= logb(x);
x=scalb(x,-exp);
if(exp-(int)logb(y) > ibig )
/* raise inexact flag and return |x| */
{ one+small; return(scalb(x,exp)); }
else y=scalb(y,-exp);
return(scalb(sqrt(x*x+y*y),exp));
}
else if(y==y) /* y is +-INF */
return(copysign(y,one));
else
return(y); /* y is NaN and x is finite */
else if(x==x) /* x is +-INF */
return (copysign(x,one));
else if(finite(y))
return(x); /* x is NaN, y is finite */
else if(y!=y) return(y); /* x and y is NaN */
else return(copysign(y,one)); /* y is INF */
}
#endif