/*	$NetBSD: ieee_ovfl.c,v 1.1 1996/04/04 06:36:27 phil Exp $	*/

/* 
 * IEEE floating point support for NS32081 and NS32381 fpus.
 * Copyright (c) 1995 Ian Dall
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * IAN DALL ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" CONDITION.
 * IAN DALL DISCLAIMS ANY LIABILITY OF ANY KIND FOR ANY DAMAGES
 * WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 */
/* 
 *	File:	ieee_ovfl.c
 *	Author:	Ian Dall
 *	Date:	November 1995
 *
 *	Handle operations which generated overflow traps.
 *
 * HISTORY
 * 14-Dec-95  Ian Dall (Ian.Dall@dsto.defence.gov.au)
 *	First release.
 *
 */
#include "ieee_internal.h"
#include <limits.h>

int ieee_ovfl(struct operand *op1, struct operand *op2,
	      struct operand *f0_op, int xopcode, state *state)
{
  int user_trap = FPC_TT_NONE;
  unsigned int fsr = state->FSR;

  fsr |= FPC_OVF;
  if (fsr & FPC_OVE) {
    /* Users trap handler will fix it */
    user_trap = FPC_TT_OVFL;
  }
  else {
    /* If destination is float or double, set to +- Infty, else
     * if byte, word or long, set to max/min int.
     */
    int sign1 = op1->data.d_bits.sign;
    int sign2 = op2->data.d_bits.sign;
    switch(xopcode) {
    case NEGF:
      sign1 ^= 1;
      /* Fall through */
    case MOVF:
    case MOVLF:
    case MOVFL:
      op2->data = infty;
      op2->data.d_bits.sign = sign1;
      break;
    case CMPF:
      /* Can't happen */
      break;
    case SUBF:
      sign1 ^= 1;
      /* Fall through */
    case ADDF:
      /* Overflow can only happen if both operands are same sign */
      op2->data = infty;
      op2->data.d_bits.sign = sign2;
      break;
    case MULF:
    case DIVF:
      op2->data = infty;
      op2->data.d_bits.sign = sign1 ^ sign2;
      break;
    case ROUNDFI:
    case TRUNCFI:
    case FLOORFI:
      op2->data.i = sign1? INT_MIN: INT_MAX;
      break;
    case SCALBF:
      op2->data = infty;
      op2->data.d_bits.sign = sign1;
      break;
    case LOGBF:
      op2->data = infty;
      op2->data.d_bits.sign = ISZERO(op1->data)? 1: 0;
      break;
    case DOTF:
      (void) ieee_dot(op1->data.d, op2->data.d, &f0_op->data.d);
      break;
    case POLYF:
      {
	union t_conv t;
	t = op2->data;
	(void) ieee_dot(f0_op->data.d, op1->data.d, &t.d);
	f0_op->data = t;
      }
      break;
    }
  }
  state->FSR = fsr;
  return user_trap;
}