1 /* $NetBSD: dfcmp.c,v 1.1 2002/06/05 01:04:24 fredette Exp $ */ 2 3 /* $OpenBSD: dfcmp.c,v 1.4 2001/03/29 03:58:17 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 * pmk1.1 27 */ 28 /* 29 * (c) Copyright 1986 HEWLETT-PACKARD COMPANY 30 * 31 * To anyone who acknowledges that this file is provided "AS IS" 32 * without any express or implied warranty: 33 * permission to use, copy, modify, and distribute this file 34 * for any purpose is hereby granted without fee, provided that 35 * the above copyright notice and this notice appears in all 36 * copies, and that the name of Hewlett-Packard Company not be 37 * used in advertising or publicity pertaining to distribution 38 * of the software without specific, written prior permission. 39 * Hewlett-Packard Company makes no representations about the 40 * suitability of this software for any purpose. 41 */ 42 43 44 #include "../spmath/float.h" 45 #include "../spmath/dbl_float.h" 46 47 /* 48 * dbl_cmp: compare two values 49 */ 50 int 51 dbl_fcmp(leftptr, rightptr, cond, status) 52 dbl_floating_point *leftptr, *rightptr; 53 unsigned int cond; /* The predicate to be tested */ 54 unsigned int *status; 55 { 56 register unsigned int leftp1, leftp2, rightp1, rightp2; 57 register int xorresult; 58 59 /* Create local copies of the numbers */ 60 Dbl_copyfromptr(leftptr,leftp1,leftp2); 61 Dbl_copyfromptr(rightptr,rightp1,rightp2); 62 /* 63 * Test for NaN 64 */ 65 if( (Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT) 66 || (Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT) ) 67 { 68 /* Check if a NaN is involved. Signal an invalid exception when 69 * comparing a signaling NaN or when comparing quiet NaNs and the 70 * low bit of the condition is set */ 71 if( ((Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT) 72 && Dbl_isnotzero_mantissa(leftp1,leftp2) 73 && (Exception(cond) || Dbl_isone_signaling(leftp1))) 74 || 75 ((Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT) 76 && Dbl_isnotzero_mantissa(rightp1,rightp2) 77 && (Exception(cond) || Dbl_isone_signaling(rightp1))) ) 78 { 79 if( Is_invalidtrap_enabled() ) { 80 Set_status_cbit(Unordered(cond)); 81 return(INVALIDEXCEPTION); 82 } 83 else Set_invalidflag(); 84 Set_status_cbit(Unordered(cond)); 85 return(NOEXCEPTION); 86 } 87 /* All the exceptional conditions are handled, now special case 88 NaN compares */ 89 else if( ((Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT) 90 && Dbl_isnotzero_mantissa(leftp1,leftp2)) 91 || 92 ((Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT) 93 && Dbl_isnotzero_mantissa(rightp1,rightp2)) ) 94 { 95 /* NaNs always compare unordered. */ 96 Set_status_cbit(Unordered(cond)); 97 return(NOEXCEPTION); 98 } 99 /* infinities will drop down to the normal compare mechanisms */ 100 } 101 /* First compare for unequal signs => less or greater or 102 * special equal case */ 103 Dbl_xortointp1(leftp1,rightp1,xorresult); 104 if( xorresult < 0 ) 105 { 106 /* left negative => less, left positive => greater. 107 * equal is possible if both operands are zeros. */ 108 if( Dbl_iszero_exponentmantissa(leftp1,leftp2) 109 && Dbl_iszero_exponentmantissa(rightp1,rightp2) ) 110 { 111 Set_status_cbit(Equal(cond)); 112 } 113 else if( Dbl_isone_sign(leftp1) ) 114 { 115 Set_status_cbit(Lessthan(cond)); 116 } 117 else 118 { 119 Set_status_cbit(Greaterthan(cond)); 120 } 121 } 122 /* Signs are the same. Treat negative numbers separately 123 * from the positives because of the reversed sense. */ 124 else if(Dbl_isequal(leftp1,leftp2,rightp1,rightp2)) 125 { 126 Set_status_cbit(Equal(cond)); 127 } 128 else if( Dbl_iszero_sign(leftp1) ) 129 { 130 /* Positive compare */ 131 if( Dbl_allp1(leftp1) < Dbl_allp1(rightp1) ) 132 { 133 Set_status_cbit(Lessthan(cond)); 134 } 135 else if( Dbl_allp1(leftp1) > Dbl_allp1(rightp1) ) 136 { 137 Set_status_cbit(Greaterthan(cond)); 138 } 139 else 140 { 141 /* Equal first parts. Now we must use unsigned compares to 142 * resolve the two possibilities. */ 143 if( Dbl_allp2(leftp2) < Dbl_allp2(rightp2) ) 144 { 145 Set_status_cbit(Lessthan(cond)); 146 } 147 else 148 { 149 Set_status_cbit(Greaterthan(cond)); 150 } 151 } 152 } 153 else 154 { 155 /* Negative compare. Signed or unsigned compares 156 * both work the same. That distinction is only 157 * important when the sign bits differ. */ 158 if( Dbl_allp1(leftp1) > Dbl_allp1(rightp1) ) 159 { 160 Set_status_cbit(Lessthan(cond)); 161 } 162 else if( Dbl_allp1(leftp1) < Dbl_allp1(rightp1) ) 163 { 164 Set_status_cbit(Greaterthan(cond)); 165 } 166 else 167 { 168 /* Equal first parts. Now we must use unsigned compares to 169 * resolve the two possibilities. */ 170 if( Dbl_allp2(leftp2) > Dbl_allp2(rightp2) ) 171 { 172 Set_status_cbit(Lessthan(cond)); 173 } 174 else 175 { 176 Set_status_cbit(Greaterthan(cond)); 177 } 178 } 179 } 180 return(NOEXCEPTION); 181 } 182