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

   1: /*
   2: char id_traper[] = "@(#)traper_.c	1.1";
   3:  * Arrange to trap integer overflow & floating underflow.
   4:  * Full of Magic! DON'T CHANGE ANYTHING !!
   5:  *
   6:  * To use from f77:
   7:  *	integer oldmsk, traper
   8:  *	oldmsk = traper (mask)
   9:  * where:
  10:  *	mask = 1 to trap integer overflow
  11:  *	mask = 2 to trap floating underflow
  12:  *	mask = 3 to trap both
  13:  *	These 2 bits will be set into the PSW.
  14:  *	The old state will be returned.
  15:  */
  16: 
  17: long traper_(msk)
  18: long    *msk;
  19: {
  20:     int old = 0;
  21: #if vax
  22: #define IOV_MASK    0140
  23:     int **s = &msk;
  24:     int psw;
  25: 
  26:     s -= 5;
  27:     psw = (int)*s;
  28:     old = (psw & IOV_MASK) >> 5;
  29:     psw = (psw & ~IOV_MASK) | ((*msk << 5) & IOV_MASK);
  30:     *s = (int *)psw;
  31: #endif	vax
  32:     return((long)old);
  33: }

Defined functions

Defined macros