sys/arch/hppa/spmath/divsim.c

   1 /*      $NetBSD: divsim.c,v 1.3 2005/12/11 12:17:40 christos Exp $      */
   2
   3 /*      $OpenBSD: divsim.c,v 1.4 2001/03/29 03:58:18 mickey Exp $       */
   4
   5 /*
   6  * Copyright 1996 1995 by Open Software Foundation, Inc.
   7  *              All Rights Reserved
   8  *
   9  * Permission to use, copy, modify, and distribute this software and
  10  * its documentation for any purpose and without fee is hereby granted,
  11  * provided that the above copyright notice appears in all copies and
  12  * that both the copyright notice and this permission notice appear in
  13  * supporting documentation.
  14  *
  15  * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
  16  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  17  * FOR A PARTICULAR PURPOSE.
  18  *
  19  * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
  20  * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
  21  * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
  22  * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
  23  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  24  *
  25  */
  26 /*
  27  * pmk1.1
  28  */
  29 /*
  30  * (c) Copyright 1986 HEWLETT-PACKARD COMPANY
  31  *
  32  * To anyone who acknowledges that this file is provided "AS IS"
  33  * without any express or implied warranty:
  34  *     permission to use, copy, modify, and distribute this file
  35  * for any purpose is hereby granted without fee, provided that
  36  * the above copyright notice and this notice appears in all
  37  * copies, and that the name of Hewlett-Packard Company not be
  38  * used in advertising or publicity pertaining to distribution
  39  * of the software without specific, written prior permission.
  40  * Hewlett-Packard Company makes no representations about the
  41  * suitability of this software for any purpose.
  42  */
  43
  44 #include <sys/cdefs.h>
  45 __KERNEL_RCSID(0, "$NetBSD: divsim.c,v 1.3 2005/12/11 12:17:40 christos Exp $");
  46
  47 #include "md.h"
  48
  49 void
  50 divsim(opnd1,opnd2,result)
  51
  52 int opnd1, opnd2;
  53 struct mdsfu_register *result;
  54 {
  55         int sign, op1_sign;
  56
  57         /* check divisor for zero */
  58         if (opnd2 == 0) {
  59                 overflow = true;
  60                 return;
  61         }
  62
  63         /* get sign of result */
  64         sign = opnd1 ^ opnd2;
  65
  66         /* get absolute value of operands */
  67         if (opnd1 < 0) {
  68                 opnd1 = -opnd1;
  69                 op1_sign = true;
  70         }
  71         else op1_sign = false;
  72         if (opnd2 < 0) opnd2 = -opnd2;
  73
  74         /* check for opnd2 == -2**31 */
  75         if (opnd2 < 0) {
  76                 if (opnd1 == opnd2) {
  77                         result_hi = 0;  /* remainder = 0 */
  78                         result_lo = 1;
  79                 }
  80                 else {
  81                         result_hi = opnd1;      /* remainder = opnd1 */
  82                         result_lo = 0;
  83                 }
  84         }
  85         else {
  86                 /* do the divide */
  87                 divu(0,opnd1,opnd2,result);
  88
  89                 /*
  90                  * check for overflow
  91                  *
  92                  * at this point, the only way we can get overflow
  93                  * is with opnd1 = -2**31 and opnd2 = -1
  94                  */
  95                 if (sign>0 && result_lo<0) {
  96                         overflow = true;
  97                         return;
  98                 }
  99         }
 100         overflow = false;
 101
 102         /* return positive residue */
 103         if (op1_sign && result_hi) {
 104                 result_hi = opnd2 - result_hi;
 105                 if (++result_lo < 0) {
 106                         overflow = true;
 107                         return;
 108                 }
 109         }
 110
 111         /* return appropriately signed result */
 112         if (sign<0) result_lo = -result_lo;
 113         return;
 114 }