4.3BSD - /usr/src/usr.lib/libF77/pow_di.c

   1: /*
   2:  * Copyright (c) 1980 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  *
   6:  *	@(#)pow_di.c	5.1	6/7/85
   7:  */
   8: 
   9: double pow_di(ap, bp)
  10: double *ap;
  11: long int *bp;
  12: {
  13: double pow, x;
  14: long int n;
  15: 
  16: pow = 1;
  17: x = *ap;
  18: n = *bp;
  19: 
  20: if(n != 0)
  21:     {
  22:     if(n < 0)
  23:         {
  24:         if(x == 0)
  25:             {
  26:             return(pow);
  27:             }
  28:         n = -n;
  29:         x = 1/x;
  30:         }
  31:     for( ; ; )
  32:         {
  33:         if(n & 01)
  34:             pow *= x;
  35:         if(n >>= 1)
  36:             x *= x;
  37:         else
  38:             break;
  39:         }
  40:     }
  41: return(pow);
  42: }

Defined functions