1 /* $NetBSD: dfcmp.c,v 1.4 2012/02/04 17:03:09 skrll 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 <sys/cdefs.h> 45 __KERNEL_RCSID(0, "$NetBSD: dfcmp.c,v 1.4 2012/02/04 17:03:09 skrll Exp $"); 46 47 #include "../spmath/float.h" 48 #include "../spmath/dbl_float.h" 49 50 /* 51 * dbl_cmp: compare two values 52 */ 53 int 54 dbl_fcmp(dbl_floating_point *leftptr, dbl_floating_point *rightptr, 55 unsigned int cond, unsigned int *status) 56 { 57 register unsigned int leftp1, leftp2, rightp1, rightp2; 58 register int xorresult; 59 60 /* Create local copies of the numbers */ 61 Dbl_copyfromptr(leftptr,leftp1,leftp2); 62 Dbl_copyfromptr(rightptr,rightp1,rightp2); 63 /* 64 * Test for NaN 65 */ 66 if( (Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT) 67 || (Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT) ) 68 { 69 /* Check if a NaN is involved. Signal an invalid exception when 70 * comparing a signaling NaN or when comparing quiet NaNs and the 71 * low bit of the condition is set */ 72 if( ((Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT) 73 && Dbl_isnotzero_mantissa(leftp1,leftp2) 74 && (Exception(cond) || Dbl_isone_signaling(leftp1))) 75 || 76 ((Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT) 77 && Dbl_isnotzero_mantissa(rightp1,rightp2) 78 && (Exception(cond) || Dbl_isone_signaling(rightp1))) ) 79 { 80 if( Is_invalidtrap_enabled() ) { 81 Set_status_cbit(Unordered(cond)); 82 return(INVALIDEXCEPTION); 83 } 84 else Set_invalidflag(); 85 Set_status_cbit(Unordered(cond)); 86 return(NOEXCEPTION); 87 } 88 /* All the exceptional conditions are handled, now special case 89 NaN compares */ 90 else if( ((Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT) 91 && Dbl_isnotzero_mantissa(leftp1,leftp2)) 92 || 93 ((Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT) 94 && Dbl_isnotzero_mantissa(rightp1,rightp2)) ) 95 { 96 /* NaNs always compare unordered. */ 97 Set_status_cbit(Unordered(cond)); 98 return(NOEXCEPTION); 99 } 100 /* infinities will drop down to the normal compare mechanisms */ 101 } 102 /* First compare for unequal signs => less or greater or 103 * special equal case */ 104 Dbl_xortointp1(leftp1,rightp1,xorresult); 105 if( xorresult < 0 ) 106 { 107 /* left negative => less, left positive => greater. 108 * equal is possible if both operands are zeros. */ 109 if( Dbl_iszero_exponentmantissa(leftp1,leftp2) 110 && Dbl_iszero_exponentmantissa(rightp1,rightp2) ) 111 { 112 Set_status_cbit(Equal(cond)); 113 } 114 else if( Dbl_isone_sign(leftp1) ) 115 { 116 Set_status_cbit(Lessthan(cond)); 117 } 118 else 119 { 120 Set_status_cbit(Greaterthan(cond)); 121 } 122 } 123 /* Signs are the same. Treat negative numbers separately 124 * from the positives because of the reversed sense. */ 125 else if(Dbl_isequal(leftp1,leftp2,rightp1,rightp2)) 126 { 127 Set_status_cbit(Equal(cond)); 128 } 129 else if( Dbl_iszero_sign(leftp1) ) 130 { 131 /* Positive compare */ 132 if( Dbl_allp1(leftp1) < Dbl_allp1(rightp1) ) 133 { 134 Set_status_cbit(Lessthan(cond)); 135 } 136 else if( Dbl_allp1(leftp1) > Dbl_allp1(rightp1) ) 137 { 138 Set_status_cbit(Greaterthan(cond)); 139 } 140 else 141 { 142 /* Equal first parts. Now we must use unsigned compares to 143 * resolve the two possibilities. */ 144 if( Dbl_allp2(leftp2) < Dbl_allp2(rightp2) ) 145 { 146 Set_status_cbit(Lessthan(cond)); 147 } 148 else 149 { 150 Set_status_cbit(Greaterthan(cond)); 151 } 152 } 153 } 154 else 155 { 156 /* Negative compare. Signed or unsigned compares 157 * both work the same. That distinction is only 158 * important when the sign bits differ. */ 159 if( Dbl_allp1(leftp1) > Dbl_allp1(rightp1) ) 160 { 161 Set_status_cbit(Lessthan(cond)); 162 } 163 else if( Dbl_allp1(leftp1) < Dbl_allp1(rightp1) ) 164 { 165 Set_status_cbit(Greaterthan(cond)); 166 } 167 else 168 { 169 /* Equal first parts. Now we must use unsigned compares to 170 * resolve the two possibilities. */ 171 if( Dbl_allp2(leftp2) > Dbl_allp2(rightp2) ) 172 { 173 Set_status_cbit(Lessthan(cond)); 174 } 175 else 176 { 177 Set_status_cbit(Greaterthan(cond)); 178 } 179 } 180 } 181 return(NOEXCEPTION); 182 } 183