1 /* $NetBSD: divsim.c,v 1.1 2002/06/05 01:04:24 fredette 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 45 #include "md.h" 46 47 void 48 divsim(opnd1,opnd2,result) 49 50 int opnd1, opnd2; 51 struct mdsfu_register *result; 52 { 53 int sign, op1_sign; 54 55 /* check divisor for zero */ 56 if (opnd2 == 0) { 57 overflow = TRUE; 58 return; 59 } 60 61 /* get sign of result */ 62 sign = opnd1 ^ opnd2; 63 64 /* get absolute value of operands */ 65 if (opnd1 < 0) { 66 opnd1 = -opnd1; 67 op1_sign = TRUE; 68 } 69 else op1_sign = FALSE; 70 if (opnd2 < 0) opnd2 = -opnd2; 71 72 /* check for opnd2 == -2**31 */ 73 if (opnd2 < 0) { 74 if (opnd1 == opnd2) { 75 result_hi = 0; /* remainder = 0 */ 76 result_lo = 1; 77 } 78 else { 79 result_hi = opnd1; /* remainder = opnd1 */ 80 result_lo = 0; 81 } 82 } 83 else { 84 /* do the divide */ 85 divu(0,opnd1,opnd2,result); 86 87 /* 88 * check for overflow 89 * 90 * at this point, the only way we can get overflow 91 * is with opnd1 = -2**31 and opnd2 = -1 92 */ 93 if (sign>0 && result_lo<0) { 94 overflow = TRUE; 95 return; 96 } 97 } 98 overflow = FALSE; 99 100 /* return positive residue */ 101 if (op1_sign && result_hi) { 102 result_hi = opnd2 - result_hi; 103 if (++result_lo < 0) { 104 overflow = TRUE; 105 return; 106 } 107 } 108 109 /* return appropriately signed result */ 110 if (sign<0) result_lo = -result_lo; 111 return; 112 } 113