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/sfcmp.c $Revision: 1.1 $ 26 * 27 * Purpose: 28 * sgl_cmp: compare two values 29 * 30 * External Interfaces: 31 * sgl_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 #include "float.h" 43 #include "sgl_float.h" 44 45 /* 46 * sgl_cmp: compare two values 47 */ 48 int 49 sgl_fcmp (sgl_floating_point * leftptr, sgl_floating_point * rightptr, 50 unsigned int cond, unsigned int *status) 51 52 /* The predicate to be tested */ 53 54 { 55 register unsigned int left, right; 56 register int xorresult; 57 58 /* Create local copies of the numbers */ 59 left = *leftptr; 60 right = *rightptr; 61 62 /* 63 * Test for NaN 64 */ 65 if( (Sgl_exponent(left) == SGL_INFINITY_EXPONENT) 66 || (Sgl_exponent(right) == SGL_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( ( (Sgl_exponent(left) == SGL_INFINITY_EXPONENT) 72 && Sgl_isnotzero_mantissa(left) 73 && (Exception(cond) || Sgl_isone_signaling(left))) 74 || 75 ( (Sgl_exponent(right) == SGL_INFINITY_EXPONENT) 76 && Sgl_isnotzero_mantissa(right) 77 && (Exception(cond) || Sgl_isone_signaling(right)) ) ) 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( ((Sgl_exponent(left) == SGL_INFINITY_EXPONENT) 90 && Sgl_isnotzero_mantissa(left)) 91 || 92 ((Sgl_exponent(right) == SGL_INFINITY_EXPONENT) 93 && Sgl_isnotzero_mantissa(right)) ) 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 Sgl_xortointp1(left,right,xorresult); 104 if( xorresult < 0 ) 105 { 106 /* left negative => less, left positive => greater. 107 * equal is possible if both operands are zeros. */ 108 if( Sgl_iszero_exponentmantissa(left) 109 && Sgl_iszero_exponentmantissa(right) ) 110 { 111 Set_status_cbit(Equal(cond)); 112 } 113 else if( Sgl_isone_sign(left) ) 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( Sgl_all(left) == Sgl_all(right) ) 125 { 126 Set_status_cbit(Equal(cond)); 127 } 128 else if( Sgl_iszero_sign(left) ) 129 { 130 /* Positive compare */ 131 if( Sgl_all(left) < Sgl_all(right) ) 132 { 133 Set_status_cbit(Lessthan(cond)); 134 } 135 else 136 { 137 Set_status_cbit(Greaterthan(cond)); 138 } 139 } 140 else 141 { 142 /* Negative compare. Signed or unsigned compares 143 * both work the same. That distinction is only 144 * important when the sign bits differ. */ 145 if( Sgl_all(left) > Sgl_all(right) ) 146 { 147 Set_status_cbit(Lessthan(cond)); 148 } 149 else 150 { 151 Set_status_cbit(Greaterthan(cond)); 152 } 153 } 154 return(NOEXCEPTION); 155 } 156