NetBSD/gnu/dist/libf2c/libF77/z_div.c

40 lines
741 B
C

#include "f2c.h"
#ifdef KR_headers
extern VOID sig_die();
VOID z_div(resx, a, b) doublecomplex *a, *b, *resx;
#else
extern void sig_die(char*, int);
void z_div(doublecomplex *resx, doublecomplex *a, doublecomplex *b)
#endif
{
double ratio, den;
double abr, abi;
doublecomplex res;
if( (abr = b->r) < 0.)
abr = - abr;
if( (abi = b->i) < 0.)
abi = - abi;
if( abr <= abi )
{
if(abi == 0)
sig_die("complex division by zero", 1);
ratio = b->r / b->i ;
den = b->i * (1 + ratio*ratio);
res.r = (a->r*ratio + a->i) / den;
res.i = (a->i*ratio - a->r) / den;
}
else
{
ratio = b->i / b->r ;
den = b->r * (1 + ratio*ratio);
res.r = (a->r + a->i*ratio) / den;
res.i = (a->i - a->r*ratio) / den;
}
resx->r = res.r;
resx->i = res.i;
}