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/* $OpenBSD: divsim.c,v 1.3 1998/07/02 19:05:12 mickey Exp $ */
/*
* Copyright 1996 1995 by Open Software Foundation, Inc.
* All Rights Reserved
*
* Permission to use, copy, modify, and distribute this software and
* its documentation for any purpose and without fee is hereby granted,
* provided that the above copyright notice appears in all copies and
* that both the copyright notice and this permission notice appear in
* supporting documentation.
*
* OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE.
*
* IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
* NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
/*
* pmk1.1
*/
/*
* (c) Copyright 1986 HEWLETT-PACKARD COMPANY
*
* To anyone who acknowledges that this file is provided "AS IS"
* without any express or implied warranty:
* permission to use, copy, modify, and distribute this file
* for any purpose is hereby granted without fee, provided that
* the above copyright notice and this notice appears in all
* copies, and that the name of Hewlett-Packard Company not be
* used in advertising or publicity pertaining to distribution
* of the software without specific, written prior permission.
* Hewlett-Packard Company makes no representations about the
* suitability of this software for any purpose.
*/
#include "md.h"
void
divsim(opnd1,opnd2,result)
int opnd1, opnd2;
struct mdsfu_register *result;
{
int sign, op1_sign;
/* check divisor for zero */
if (opnd2 == 0) {
overflow = TRUE;
return;
}
/* get sign of result */
sign = opnd1 ^ opnd2;
/* get absolute value of operands */
if (opnd1 < 0) {
opnd1 = -opnd1;
op1_sign = TRUE;
}
else op1_sign = FALSE;
if (opnd2 < 0) opnd2 = -opnd2;
/* check for opnd2 == -2**31 */
if (opnd2 < 0) {
if (opnd1 == opnd2) {
result_hi = 0; /* remainder = 0 */
result_lo = 1;
}
else {
result_hi = opnd1; /* remainder = opnd1 */
result_lo = 0;
}
}
else {
/* do the divide */
divu(0,opnd1,opnd2,result);
/*
* check for overflow
*
* at this point, the only way we can get overflow
* is with opnd1 = -2**31 and opnd2 = -1
*/
if (sign>0 && result_lo<0) {
overflow = TRUE;
return;
}
}
overflow = FALSE;
/* return positive residue */
if (op1_sign && result_hi) {
result_hi = opnd2 - result_hi;
if (++result_lo < 0) {
overflow = TRUE;
return;
}
}
/* return appropriately signed result */
if (sign<0) result_lo = -result_lo;
return;
}
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