Implement csqrtl().

This commit is contained in:
David Schultz 2008-03-30 20:07:15 +00:00
parent 84c1c0a1ca
commit 511dd36b32
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=177761
6 changed files with 137 additions and 13 deletions

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@ -60,6 +60,8 @@ float crealf(float complex);
long double creall(long double complex);
double complex csqrt(double complex);
float complex csqrtf(float complex);
long double complex
csqrtl(long double complex);
__END_DECLS

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@ -80,7 +80,7 @@ COMMON_SRCS+= s_copysignl.c s_fabsl.c s_llrintl.c s_lrintl.c s_modfl.c
.if ${LDBL_PREC} != 53
# If long double != double use these; otherwise, we alias the double versions.
COMMON_SRCS+= e_hypotl.c e_sqrtl.c k_cosl.c k_sinl.c k_tanl.c \
s_ceill.c s_cosl.c s_exp2l.c s_floorl.c s_fmal.c \
s_ceill.c s_cosl.c s_csqrtl.c s_exp2l.c s_floorl.c s_fmal.c \
s_frexpl.c s_logbl.c s_nanl.c s_nextafterl.c s_nexttoward.c \
s_rintl.c s_scalbnl.c s_sinl.c s_tanl.c s_truncl.c w_cabsl.c
.endif
@ -127,7 +127,7 @@ MLINKS+=cimag.3 cimagf.3 cimag.3 cimagl.3 \
MLINKS+=copysign.3 copysignf.3 copysign.3 copysignl.3
MLINKS+=cos.3 cosf.3 cos.3 cosl.3
MLINKS+=cosh.3 coshf.3
MLINKS+=csqrt.3 csqrtf.3
MLINKS+=csqrt.3 csqrtf.3 csqrt.3 csqrtl.3
MLINKS+=erf.3 erfc.3 erf.3 erff.3 erf.3 erfcf.3
MLINKS+=exp.3 expm1.3 exp.3 expm1f.3 exp.3 pow.3 exp.3 powf.3 \
exp.3 exp2.3 exp.3 exp2f.3 exp.3 exp2l.3 exp.3 expf.3

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@ -205,4 +205,5 @@ FBSD_1.1 {
sqrtl;
hypotl;
cabsl;
csqrtl;
};

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@ -1,4 +1,4 @@
.\" Copyright (c) 2007 David Schultz <das@FreeBSD.org>
.\" Copyright (c) 2007-2008 David Schultz <das@FreeBSD.org>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
@ -24,12 +24,13 @@
.\"
.\" $FreeBSD$
.\"
.Dd December 14, 2007
.Dd March 30, 2008
.Dt CSQRT 3
.Os
.Sh NAME
.Nm csqrt ,
.Nm csqrtf
.Nm csqrtf ,
.Nm csqrtl
.Nd complex square root functions
.Sh LIBRARY
.Lb libm
@ -39,18 +40,22 @@
.Fn csqrt "double complex z"
.Ft float complex
.Fn csqrtf "float complex z"
.Ft long double complex
.Fn csqrtl "long double complex z"
.Sh DESCRIPTION
The
.Fn csqrt
.Fn csqrt ,
.Fn csqrtf ,
and
.Fn csqrtf
.Fn csqrtl
functions compute the square root of
.Fa z
in the complex plane, with a branch cut along the negative real axis.
In other words,
.Fn csqrt
.Fn csqrt ,
.Fn csqrtf ,
and
.Fn csqrtf
.Fn csqrtl
always return the square root whose real part is non-negative.
.Sh RETURN VALUES
These functions return the requested square root.
@ -83,12 +88,15 @@ an \*(Na is generated, an invalid exception will be thrown.
.Xr math 3 ,
.Sh STANDARDS
The
.Fn csqrt
.Fn csqrt ,
.Fn csqrtf ,
and
.Fn csqrtf
.Fn csqrtl
functions conform to
.St -isoC-99 .
.Sh BUGS
For
.Fn csqrt ,
inexact results are not correctly rounded in general.
.Fn csqrt
and
.Fn csqrtl ,
inexact results are not always correctly rounded.

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@ -28,6 +28,7 @@
__FBSDID("$FreeBSD$");
#include <complex.h>
#include <float.h>
#include <math.h>
#include "math_private.h"
@ -105,3 +106,7 @@ csqrt(double complex z)
else
return (result);
}
#if LDBL_MANT_DIG == 53
__weak_reference(csqrt, csqrtl);
#endif

108
lib/msun/src/s_csqrtl.c Normal file
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@ -0,0 +1,108 @@
/*-
* Copyright (c) 2007-2008 David Schultz <das@FreeBSD.ORG>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <complex.h>
#include <float.h>
#include <math.h>
#include "math_private.h"
/*
* gcc doesn't implement complex multiplication or division correctly,
* so we need to handle infinities specially. We turn on this pragma to
* notify conforming c99 compilers that the fast-but-incorrect code that
* gcc generates is acceptable, since the special cases have already been
* handled.
*/
#pragma STDC CX_LIMITED_RANGE on
/* We risk spurious overflow for components >= LDBL_MAX / (1 + sqrt(2)). */
#define THRESH (LDBL_MAX / 2.414213562373095048801688724209698L)
long double complex
csqrtl(long double complex z)
{
long double complex result;
long double a, b;
long double t;
int scale;
a = creall(z);
b = cimagl(z);
/* Handle special cases. */
if (z == 0)
return (cpackl(0, b));
if (isinf(b))
return (cpackl(INFINITY, b));
if (isnan(a)) {
t = (b - b) / (b - b); /* raise invalid if b is not a NaN */
return (cpackl(a, t)); /* return NaN + NaN i */
}
if (isinf(a)) {
/*
* csqrt(inf + NaN i) = inf + NaN i
* csqrt(inf + y i) = inf + 0 i
* csqrt(-inf + NaN i) = NaN +- inf i
* csqrt(-inf + y i) = 0 + inf i
*/
if (signbit(a))
return (cpackl(fabsl(b - b), copysignl(a, b)));
else
return (cpackl(a, copysignl(b - b, b)));
}
/*
* The remaining special case (b is NaN) is handled just fine by
* the normal code path below.
*/
/* Scale to avoid overflow. */
if (fabsl(a) >= THRESH || fabsl(b) >= THRESH) {
a *= 0.25;
b *= 0.25;
scale = 1;
} else {
scale = 0;
}
/* Algorithm 312, CACM vol 10, Oct 1967. */
if (a >= 0) {
t = sqrtl((a + hypotl(a, b)) * 0.5);
result = cpackl(t, b / (2 * t));
} else {
t = sqrtl((-a + hypotl(a, b)) * 0.5);
result = cpackl(fabsl(b) / (2 * t), copysignl(t, b));
}
/* Rescale. */
if (scale)
return (result * 2);
else
return (result);
}