4.3BSD - /usr/src/new/icon/operators/minus.c

   1: #include "../h/rt.h"
   2: 
   3: /*
   4:  * x - y - subtract y from x.
   5:  */
   6: 
   7: minus(nargs, arg2, arg1, arg0)
   8: int nargs;
   9: struct descrip arg2, arg1, arg0;
  10:    {
  11:    register int t1, t2;
  12:    union numeric n1, n2;
  13:    extern long cksub();
  14: 
  15:    SetBound;
  16:    /*
  17:     * x and y must be numeric.  Save the cvnum return values for later use.
  18:     */
  19:    if ((t1 = cvnum(&arg1, &n1)) == NULL)
  20:       runerr(102, &arg1);
  21:    if ((t2 = cvnum(&arg2, &n2)) == NULL)
  22:       runerr(102, &arg2);
  23: 
  24:    if (t1 == T_LONGINT && t2 == T_LONGINT)
  25:       /*
  26:        * Both x and y are integers.  Perform integer subtraction using
  27:        *  cksub (to check for overflow) and place the result in arg0 as
  28:        *  the return value.
  29:        */
  30:       mkint(cksub(n1.integer, n2.integer), &arg0);
  31:    else {
  32:       /*
  33:        * Either x or y is real, convert the other to a real, perform
  34:        *  the subtraction and place the result in arg0 as the return value.
  35:        */
  36:       if (t1 == T_LONGINT)
  37:          n1.real = n1.integer;
  38:       if (t2 == T_LONGINT)
  39:          n2.real = n2.integer;
  40:       mkreal(n1.real - n2.real, &arg0);
  41:       }
  42:    ClearBound;
  43:    }
  44: 
  45: Opblock(minus,2,"-")

Defined functions