casinl.c revision 25c28e83beb90e7c80452a7c818c5e6f73a07dc8
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma weak casinl = __casinl
#include "libm.h" /* asinl/atanl/fabsl/isinfl/log1pl/logl/sqrtl */
#include "complex_wrapper.h"
#include "longdouble.h"
/* INDENT OFF */
static const long double
zero = 0.0L,
one = 1.0L,
Acrossover = 1.5L,
Bcrossover = 0.6417L,
half = 0.5L,
ln2 = 6.931471805599453094172321214581765680755e-0001L,
Foursqrtu = 7.3344154702193886624856495681939326638255e-2466L, /* 2**-8189 */
#if defined(__x86)
E = 5.4210108624275221700372640043497085571289e-20L, /* 2**-64 */
pi_4 = 0.7853981633974483095739921312272713294078130L,
pi_4_l = 4.1668714592604391641479322342670193036704898e-20L,
pi_2 = 1.5707963267948966191479842624545426588156260L,
pi_2_l = 8.3337429185208783282958644685340386073409796e-20L;
#else
E = 9.6296497219361792652798897129246365926905e-35L, /* 2**-113 */
pi_4 = 0.7853981633974483096156608458198756993697670L,
pi_4_l = 2.1679525325309452561992610065108379921905808e-35L,
pi_2 = 1.5707963267948966192313216916397513987395340L,
pi_2_l = 4.3359050650618905123985220130216759843811616e-35L;
#endif
/* INDENT ON */
#if defined(__x86)
static const int ip1 = 0x40400000; /* 2**65 */
#else
static const int ip1 = 0x40710000; /* 2**114 */
#endif
ldcomplex
casinl(ldcomplex z) {
long double x, y, t, R, S, A, Am1, B, y2, xm1, xp1, Apx;
int ix, iy, hx, hy;
ldcomplex ans;
x = LD_RE(z);
y = LD_IM(z);
hx = HI_XWORD(x);
hy = HI_XWORD(y);
ix = hx & 0x7fffffff;
iy = hy & 0x7fffffff;
x = fabsl(x);
y = fabsl(y);
/* special cases */
/* x is inf or NaN */
if (ix >= 0x7fff0000) { /* x is inf or NaN */
if (isinfl(x)) { /* x is INF */
LD_IM(ans) = x;
if (iy >= 0x7fff0000) {
if (isinfl(y))
/* casin(inf + i inf) = pi/4 + i inf */
LD_RE(ans) = pi_4 + pi_4_l;
else /* casin(inf + i NaN) = NaN + i inf */
LD_RE(ans) = y + y;
} else /* casin(inf + iy) = pi/2 + i inf */
LD_RE(ans) = pi_2 + pi_2_l;
} else { /* x is NaN */
if (iy >= 0x7fff0000) {
/* INDENT OFF */
/*
* casin(NaN + i inf) = NaN + i inf
* casin(NaN + i NaN) = NaN + i NaN
*/
/* INDENT ON */
LD_IM(ans) = y + y;
LD_RE(ans) = x + x;
} else {
/* INDENT OFF */
/* casin(NaN + i y ) = NaN + i NaN */
/* INDENT ON */
LD_IM(ans) = LD_RE(ans) = x + y;
}
}
if (hx < 0)
LD_RE(ans) = -LD_RE(ans);
if (hy < 0)
LD_IM(ans) = -LD_IM(ans);
return (ans);
}
/* casin(+0 + i 0) = 0 + i 0. */
if (x == zero && y == zero)
return (z);
if (iy >= 0x7fff0000) { /* y is inf or NaN */
if (isinfl(y)) { /* casin(x + i inf) = 0 + i inf */
LD_IM(ans) = y;
LD_RE(ans) = zero;
} else { /* casin(x + i NaN) = NaN + i NaN */
LD_IM(ans) = x + y;
if (x == zero)
LD_RE(ans) = x;
else
LD_RE(ans) = y;
}
if (hx < 0)
LD_RE(ans) = -LD_RE(ans);
if (hy < 0)
LD_IM(ans) = -LD_IM(ans);
return (ans);
}
if (y == zero) { /* region 1: y=0 */
if (ix < 0x3fff0000) { /* |x| < 1 */
LD_RE(ans) = asinl(x);
LD_IM(ans) = zero;
} else {
LD_RE(ans) = pi_2 + pi_2_l;
if (ix >= ip1) /* |x| >= i386 ? 2**65 : 2**114 */
LD_IM(ans) = ln2 + logl(x);
else if (ix >= 0x3fff8000) /* x > Acrossover */
LD_IM(ans) = logl(x + sqrtl((x - one) * (x +
one)));
else {
xm1 = x - one;
LD_IM(ans) = log1pl(xm1 + sqrtl(xm1 * (x +
one)));
}
}
} else if (y <= E * fabsl(x - one)) { /* region 2: y < tiny*|x-1| */
if (ix < 0x3fff0000) { /* x < 1 */
LD_RE(ans) = asinl(x);
LD_IM(ans) = y / sqrtl((one + x) * (one - x));
} else {
LD_RE(ans) = pi_2 + pi_2_l;
if (ix >= ip1) /* i386 ? 2**65 : 2**114 */
LD_IM(ans) = ln2 + logl(x);
else if (ix >= 0x3fff8000) /* x > Acrossover */
LD_IM(ans) = logl(x + sqrtl((x - one) * (x +
one)));
else
LD_IM(ans) = log1pl((x - one) + sqrtl((x -
one) * (x + one)));
}
} else if (y < Foursqrtu) { /* region 3 */
t = sqrtl(y);
LD_RE(ans) = pi_2 - (t - pi_2_l);
LD_IM(ans) = t;
} else if (E * y - one >= x) { /* region 4 */
LD_RE(ans) = x / y; /* need to fix underflow cases */
LD_IM(ans) = ln2 + logl(y);
} else if (ix >= 0x5ffb0000 || iy >= 0x5ffb0000) {
/* region 5: x+1 and y are both (>= sqrt(max)/8) i.e. 2**8188 */
t = x / y;
LD_RE(ans) = atanl(t);
LD_IM(ans) = ln2 + logl(y) + half * log1pl(t * t);
} else if (x < Foursqrtu) {
/* region 6: x is very small, < 4sqrt(min) */
A = sqrtl(one + y * y);
LD_RE(ans) = x / A; /* may underflow */
if (iy >= 0x3fff8000) /* if y > Acrossover */
LD_IM(ans) = logl(y + A);
else
LD_IM(ans) = half * log1pl((y + y) * (y + A));
} else { /* safe region */
y2 = y * y;
xp1 = x + one;
xm1 = x - one;
R = sqrtl(xp1 * xp1 + y2);
S = sqrtl(xm1 * xm1 + y2);
A = half * (R + S);
B = x / A;
if (B <= Bcrossover)
LD_RE(ans) = asinl(B);
else { /* use atan and an accurate approx to a-x */
Apx = A + x;
if (x <= one)
LD_RE(ans) = atanl(x / sqrtl(half * Apx * (y2 /
(R + xp1) + (S - xm1))));
else
LD_RE(ans) = atanl(x / (y * sqrtl(half * (Apx /
(R + xp1) + Apx / (S + xm1)))));
}
if (A <= Acrossover) {
/* use log1p and an accurate approx to A-1 */
if (x < one)
Am1 = half * (y2 / (R + xp1) + y2 / (S - xm1));
else
Am1 = half * (y2 / (R + xp1) + (S + xm1));
LD_IM(ans) = log1pl(Am1 + sqrtl(Am1 * (A + one)));
} else {
LD_IM(ans) = logl(A + sqrtl(A * A - one));
}
}
if (hx < 0)
LD_RE(ans) = -LD_RE(ans);
if (hy < 0)
LD_IM(ans) = -LD_IM(ans);
return (ans);
}