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authorIan Moffett <ian@osmora.org>2024-03-07 17:28:00 -0500
committerIan Moffett <ian@osmora.org>2024-03-07 17:28:32 -0500
commitbd5969fc876a10b18613302db7087ef3c40f18e1 (patch)
tree7c2b8619afe902abf99570df2873fbdf40a4d1a1 /lib/mlibc/options/ansi/generic/complex/casin.c
parenta95b38b1b92b172e6cc4e8e56a88a30cc65907b0 (diff)
lib: Add mlibc
Signed-off-by: Ian Moffett <ian@osmora.org>
Diffstat (limited to 'lib/mlibc/options/ansi/generic/complex/casin.c')
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+/* $NetBSD: casin.c,v 1.1 2007/08/20 16:01:31 drochner Exp $ */
+
+/*-
+ * Copyright (c) 2007 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software written by Stephen L. Moshier.
+ * It is redistributed by the NetBSD Foundation by permission of the author.
+ *
+ * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
+ *
+ * imported and modified include for newlib 2010/10/03
+ * Marco Atzeri <marco_atzeri@yahoo.it>
+ */
+
+/*
+FUNCTION
+ <<casin>>, <<casinf>>---complex arc sine
+
+INDEX
+ casin
+INDEX
+ casinf
+
+ANSI_SYNOPSIS
+ #include <complex.h>
+ double complex casin(double complex <[z]>);
+ float complex casinf(float complex <[z]>);
+
+
+DESCRIPTION
+ These functions compute the complex arc sine of <[z]>,
+ with branch cuts outside the interval [-1, +1] along the real axis.
+
+ <<casinf>> is identical to <<casin>>, except that it performs
+ its calculations on <<floats complex>>.
+
+RETURNS
+ @ifnottex
+ These functions return the complex arc sine value, in the range
+ of a strip mathematically unbounded along the imaginary axis
+ and in the interval [-pi/2, +pi/2] along the real axis.
+ @end ifnottex
+ @tex
+ These functions return the complex arc sine value, in the range
+ of a strip mathematically unbounded along the imaginary axis
+ and in the interval [$-\pi/2$, $+\pi/2$] along the real axis.
+ @end tex
+
+PORTABILITY
+ <<casin>> and <<casinf>> are ISO C99
+
+QUICKREF
+ <<casin>> and <<casinf>> are ISO C99
+
+*/
+
+
+#include <complex.h>
+#include <math.h>
+
+#ifdef __weak_alias
+__weak_alias(casin, _casin)
+#endif
+
+double complex
+casin(double complex z)
+{
+ double complex w;
+ double complex ca, ct, zz, z2;
+ double x, y;
+
+ x = creal(z);
+ y = cimag(z);
+
+#if 0 /* MD: test is incorrect, casin(>1) is defined */
+ if (y == 0.0) {
+ if (fabs(x) > 1.0) {
+ w = M_PI_2 + 0.0 * I;
+#if 0
+ mtherr ("casin", DOMAIN);
+#endif
+ } else {
+ w = asin(x) + 0.0 * I;
+ }
+ return w;
+ }
+#endif
+
+/* Power series expansion */
+/*
+b = cabs(z);
+if( b < 0.125 )
+{
+z2.r = (x - y) * (x + y);
+z2.i = 2.0 * x * y;
+
+cn = 1.0;
+n = 1.0;
+ca.r = x;
+ca.i = y;
+sum.r = x;
+sum.i = y;
+do
+ {
+ ct.r = z2.r * ca.r - z2.i * ca.i;
+ ct.i = z2.r * ca.i + z2.i * ca.r;
+ ca.r = ct.r;
+ ca.i = ct.i;
+
+ cn *= n;
+ n += 1.0;
+ cn /= n;
+ n += 1.0;
+ b = cn/n;
+
+ ct.r *= b;
+ ct.i *= b;
+ sum.r += ct.r;
+ sum.i += ct.i;
+ b = fabs(ct.r) + fabs(ct.i);
+ }
+while( b > MACHEP );
+w->r = sum.r;
+w->i = sum.i;
+return;
+}
+*/
+
+
+ ca = x + y * I;
+ ct = ca * I;
+ /* sqrt( 1 - z*z) */
+ /* cmul( &ca, &ca, &zz ) */
+ /*x * x - y * y */
+ zz = (x - y) * (x + y) + (2.0 * x * y) * I;
+
+ zz = 1.0 - creal(zz) - cimag(zz) * I;
+ z2 = csqrt(zz);
+
+ zz = ct + z2;
+ zz = clog(zz);
+ /* multiply by 1/i = -i */
+ w = zz * (-1.0 * I);
+ return w;
+}