newlib-cygwin/winsup/mingw/mingwex/complex/csqrtl.c

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/* csqrtl.c */
/*
Contributed by Danny Smith
2005-01-04
*/
#include <math.h>
#include <complex.h>
long double complex csqrtl (long double complex Z)
{
long double complex Res;
long double r;
long double x = __real__ Z;
long double y = __imag__ Z;
if (y == 0.0L)
{
if (x < 0.0L)
{
__real__ Res = 0.0L;
__imag__ Res = sqrtl (-x);
}
else
{
__real__ Res = sqrtl (x);
__imag__ Res = 0.0L;
}
}
else if (x == 0.0L)
{
r = sqrtl(0.5L * fabsl (y));
__real__ Res = r;
__imag__ Res = y > 0 ? r : -r;
}
else
{
long double t = sqrtl (2.0L * (hypotl (__real__ Z, __imag__ Z) + fabsl (x)));
long double u = t / 2.0L;
if ( x > 0.0L)
{
__real__ Res = u;
__imag__ Res = y / t;
}
else
{
__real__ Res = fabsl (y / t);
__imag__ Res = y < 0 ? -u : u;
}
}
return Res;
}