aboutsummaryrefslogtreecommitdiff
path: root/math/s_csqrtf.c
diff options
context:
space:
mode:
Diffstat (limited to 'math/s_csqrtf.c')
-rw-r--r--math/s_csqrtf.c112
1 files changed, 112 insertions, 0 deletions
diff --git a/math/s_csqrtf.c b/math/s_csqrtf.c
new file mode 100644
index 0000000..2fba69c
--- /dev/null
+++ b/math/s_csqrtf.c
@@ -0,0 +1,112 @@
+/* Complex square root of float value.
+ Copyright (C) 1997, 1998, 2005 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Based on an algorithm by Stephen L. Moshier <moshier@world.std.com>.
+ Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <complex.h>
+#include <math.h>
+
+#include "math_private.h"
+
+
+__complex__ float
+__csqrtf (__complex__ float x)
+{
+ __complex__ float res;
+ int rcls = fpclassify (__real__ x);
+ int icls = fpclassify (__imag__ x);
+
+ if (rcls <= FP_INFINITE || icls <= FP_INFINITE)
+ {
+ if (icls == FP_INFINITE)
+ {
+ __real__ res = HUGE_VALF;
+ __imag__ res = __imag__ x;
+ }
+ else if (rcls == FP_INFINITE)
+ {
+ if (__real__ x < 0.0)
+ {
+ __real__ res = icls == FP_NAN ? __nanf ("") : 0;
+ __imag__ res = __copysignf (HUGE_VALF, __imag__ x);
+ }
+ else
+ {
+ __real__ res = __real__ x;
+ __imag__ res = (icls == FP_NAN
+ ? __nanf ("") : __copysignf (0.0, __imag__ x));
+ }
+ }
+ else
+ {
+ __real__ res = __nanf ("");
+ __imag__ res = __nanf ("");
+ }
+ }
+ else
+ {
+ if (icls == FP_ZERO)
+ {
+ if (__real__ x < 0.0)
+ {
+ __real__ res = 0.0;
+ __imag__ res = __copysignf (__ieee754_sqrtf (-__real__ x),
+ __imag__ x);
+ }
+ else
+ {
+ __real__ res = fabsf (__ieee754_sqrtf (__real__ x));
+ __imag__ res = __copysignf (0.0, __imag__ x);
+ }
+ }
+ else if (rcls == FP_ZERO)
+ {
+ float r = __ieee754_sqrtf (0.5 * fabsf (__imag__ x));
+
+ __real__ res = r;
+ __imag__ res = __copysignf (r, __imag__ x);
+ }
+ else
+ {
+ float d, r, s;
+
+ d = __ieee754_hypotf (__real__ x, __imag__ x);
+ /* Use the identity 2 Re res Im res = Im x
+ to avoid cancellation error in d +/- Re x. */
+ if (__real__ x > 0)
+ {
+ r = __ieee754_sqrtf (0.5f * d + 0.5f * __real__ x);
+ s = (0.5f * __imag__ x) / r;
+ }
+ else
+ {
+ s = __ieee754_sqrtf (0.5f * d - 0.5f * __real__ x);
+ r = fabsf ((0.5f * __imag__ x) / s);
+ }
+
+ __real__ res = r;
+ __imag__ res = __copysignf (s, __imag__ x);
+ }
+ }
+
+ return res;
+}
+#ifndef __csqrtf
+weak_alias (__csqrtf, csqrtf)
+#endif