diff options
Diffstat (limited to 'gcc/f/runtime/libF77/z_sqrt.c')
-rw-r--r-- | gcc/f/runtime/libF77/z_sqrt.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/gcc/f/runtime/libF77/z_sqrt.c b/gcc/f/runtime/libF77/z_sqrt.c new file mode 100644 index 00000000000..f5db5651991 --- /dev/null +++ b/gcc/f/runtime/libF77/z_sqrt.c @@ -0,0 +1,33 @@ +#include "f2c.h" + +#ifdef KR_headers +double sqrt(), f__cabs(); +VOID z_sqrt(resx, z) doublecomplex *resx, *z; +#else +#undef abs +#include <math.h> +extern double f__cabs(double, double); +void z_sqrt(doublecomplex *resx, doublecomplex *z) +#endif +{ +double mag; +doublecomplex res; + +if( (mag = f__cabs(z->r, z->i)) == 0.) + res.r = res.i = 0.; +else if(z->r > 0) + { + res.r = sqrt(0.5 * (mag + z->r) ); + res.i = z->i / res.r / 2; + } +else + { + res.i = sqrt(0.5 * (mag - z->r) ); + if(z->i < 0) + res.i = - res.i; + res.r = z->i / res.i / 2; + } + +resx->r = res.r; +resx->i = res.i; +} |