2.9BSD - /usr/src/lib/libF77/pow_zi.c

   1: /*
   2:  *	"@(#)pow_zi.c	1.1"
   3:  */
   4: 
   5: #include "complex"
   6: 
   7: pow_zi(p, a, b)     /* p = a**b  */
   8: dcomplex *p, *a;
   9: long int *b;
  10: {
  11: long int n;
  12: double t;
  13: dcomplex x;
  14: 
  15: n = *b;
  16: p->dreal = 1;
  17: p->dimag = 0;
  18: 
  19: if(n == 0)
  20:     return;
  21: if(n < 0)
  22:     {
  23:     n = -n;
  24:     z_div(&x, p, a);
  25:     }
  26: else
  27:     {
  28:     x.dreal = a->dreal;
  29:     x.dimag = a->dimag;
  30:     }
  31: 
  32: for( ; ; )
  33:     {
  34:     if(n & 01)
  35:         {
  36:         t = p->dreal * x.dreal - p->dimag * x.dimag;
  37:         p->dimag = p->dreal * x.dimag + p->dimag * x.dreal;
  38:         p->dreal = t;
  39:         }
  40:     if(n >>= 1)
  41:         {
  42:         t = x.dreal * x.dreal - x.dimag * x.dimag;
  43:         x.dimag = 2 * x.dreal * x.dimag;
  44:         x.dreal = t;
  45:         }
  46:     else
  47:         break;
  48:     }
  49: }

Defined functions