4.3BSD - /usr/src/lib/libc/gen/frexp.c

   1: #if defined(LIBC_SCCS) && !defined(lint)
   2: static char sccsid[] = "@(#)frexp.c	5.2 (Berkeley) 3/9/86";
   3: #endif LIBC_SCCS and not lint
   4: 
   5: /*
   6:  *	the call
   7:  *		x = frexp(arg,&exp);
   8:  *	must return a double fp quantity x which is <1.0
   9:  *	and the corresponding binary exponent "exp".
  10:  *	such that
  11:  *		arg = x*2^exp
  12:  *	if the argument is 0.0, return 0.0 mantissa and 0 exponent.
  13:  */
  14: 
  15: double
  16: frexp(x,i)
  17: double x;
  18: int *i;
  19: {
  20:     int neg;
  21:     int j;
  22:     j = 0;
  23:     neg = 0;
  24:     if(x<0){
  25:         x = -x;
  26:         neg = 1;
  27:         }
  28:     if(x>=1.0)
  29:         while(x>=1.0){
  30:             j = j+1;
  31:             x = x/2;
  32:             }
  33:     else if(x<0.5 && x != 0.0)
  34:         while(x<0.5){
  35:             j = j-1;
  36:             x = 2*x;
  37:             }
  38:     *i = j;
  39:     if(neg) x = -x;
  40:     return(x);
  41:     }

Defined functions

Defined variables