1 /* 2 * Linux/PA-RISC Project (http://www.parisc-linux.org/) 3 * 4 * Floating-point emulation code 5 * Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2, or (at your option) 10 * any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21 /* 22 * BEGIN_DESC 23 * 24 * File: 25 * @(#) pa/spmath/dfcmp.c $Revision: 1.1 $ 26 * 27 * Purpose: 28 * dbl_cmp: compare two values 29 * 30 * External Interfaces: 31 * dbl_fcmp(leftptr, rightptr, cond, status) 32 * 33 * Internal Interfaces: 34 * 35 * Theory: 36 * <<please update with a overview of the operation of this file>> 37 * 38 * END_DESC 39 */ 40 41 42 43 #include "float.h" 44 #include "dbl_float.h" 45 46 /* 47 * dbl_cmp: compare two values 48 */ 49 int 50 dbl_fcmp (dbl_floating_point * leftptr, dbl_floating_point * rightptr, 51 unsigned int cond, unsigned int *status) 52 53 /* The predicate to be tested */ 54 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