gcc/f/runtime/libF77/z_div.c

   1 #include "f2c.h"
   2
   3 #ifdef KR_headers
   4 extern VOID sig_die();
   5 VOID z_div(resx, a, b) doublecomplex *a, *b, *resx;
   6 #else
   7 extern void sig_die(char*, int);
   8 void z_div(doublecomplex *resx, doublecomplex *a, doublecomplex *b)
   9 #endif
  10 {
  11 double ratio, den;
  12 double abr, abi;
  13 doublecomplex res;
  14
  15 if( (abr = b->r) < 0.)
  16         abr = - abr;
  17 if( (abi = b->i) < 0.)
  18         abi = - abi;
  19 if( abr <= abi )
  20         {
  21         if(abi == 0)
  22                 sig_die("complex division by zero", 1);
  23         ratio = b->r / b->i ;
  24         den = b->i * (1 + ratio*ratio);
  25         res.r = (a->r*ratio + a->i) / den;
  26         res.i = (a->i*ratio - a->r) / den;
  27         }
  28
  29 else
  30         {
  31         ratio = b->i / b->r ;
  32         den = b->r * (1 + ratio*ratio);
  33         res.r = (a->r + a->i*ratio) / den;
  34         res.i = (a->i - a->r*ratio) / den;
  35         }
  36
  37 resx->r = res.r;
  38 resx->i = res.i;
  39 }