comparetf2.c revision 1.1.1.1
1//===-- lib/comparetf2.c - Quad-precision comparisons -------------*- C -*-===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8// 9// // This file implements the following soft-float comparison routines: 10// 11// __eqtf2 __getf2 __unordtf2 12// __letf2 __gttf2 13// __lttf2 14// __netf2 15// 16// The semantics of the routines grouped in each column are identical, so there 17// is a single implementation for each, and wrappers to provide the other names. 18// 19// The main routines behave as follows: 20// 21// __letf2(a,b) returns -1 if a < b 22// 0 if a == b 23// 1 if a > b 24// 1 if either a or b is NaN 25// 26// __getf2(a,b) returns -1 if a < b 27// 0 if a == b 28// 1 if a > b 29// -1 if either a or b is NaN 30// 31// __unordtf2(a,b) returns 0 if both a and b are numbers 32// 1 if either a or b is NaN 33// 34// Note that __letf2( ) and __getf2( ) are identical except in their handling of 35// NaN values. 36// 37//===----------------------------------------------------------------------===// 38 39#define QUAD_PRECISION 40#include "fp_lib.h" 41 42#if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT) 43enum LE_RESULT { LE_LESS = -1, LE_EQUAL = 0, LE_GREATER = 1, LE_UNORDERED = 1 }; 44 45COMPILER_RT_ABI enum LE_RESULT __letf2(fp_t a, fp_t b) { 46 47 const srep_t aInt = toRep(a); 48 const srep_t bInt = toRep(b); 49 const rep_t aAbs = aInt & absMask; 50 const rep_t bAbs = bInt & absMask; 51 52 // If either a or b is NaN, they are unordered. 53 if (aAbs > infRep || bAbs > infRep) 54 return LE_UNORDERED; 55 56 // If a and b are both zeros, they are equal. 57 if ((aAbs | bAbs) == 0) 58 return LE_EQUAL; 59 60 // If at least one of a and b is positive, we get the same result comparing 61 // a and b as signed integers as we would with a floating-point compare. 62 if ((aInt & bInt) >= 0) { 63 if (aInt < bInt) 64 return LE_LESS; 65 else if (aInt == bInt) 66 return LE_EQUAL; 67 else 68 return LE_GREATER; 69 } else { 70 // Otherwise, both are negative, so we need to flip the sense of the 71 // comparison to get the correct result. (This assumes a twos- or ones- 72 // complement integer representation; if integers are represented in a 73 // sign-magnitude representation, then this flip is incorrect). 74 if (aInt > bInt) 75 return LE_LESS; 76 else if (aInt == bInt) 77 return LE_EQUAL; 78 else 79 return LE_GREATER; 80 } 81} 82 83#if defined(__ELF__) 84// Alias for libgcc compatibility 85COMPILER_RT_ALIAS(__letf2, __cmptf2) 86#endif 87COMPILER_RT_ALIAS(__letf2, __eqtf2) 88COMPILER_RT_ALIAS(__letf2, __lttf2) 89COMPILER_RT_ALIAS(__letf2, __netf2) 90 91enum GE_RESULT { 92 GE_LESS = -1, 93 GE_EQUAL = 0, 94 GE_GREATER = 1, 95 GE_UNORDERED = -1 // Note: different from LE_UNORDERED 96}; 97 98COMPILER_RT_ABI enum GE_RESULT __getf2(fp_t a, fp_t b) { 99 100 const srep_t aInt = toRep(a); 101 const srep_t bInt = toRep(b); 102 const rep_t aAbs = aInt & absMask; 103 const rep_t bAbs = bInt & absMask; 104 105 if (aAbs > infRep || bAbs > infRep) 106 return GE_UNORDERED; 107 if ((aAbs | bAbs) == 0) 108 return GE_EQUAL; 109 if ((aInt & bInt) >= 0) { 110 if (aInt < bInt) 111 return GE_LESS; 112 else if (aInt == bInt) 113 return GE_EQUAL; 114 else 115 return GE_GREATER; 116 } else { 117 if (aInt > bInt) 118 return GE_LESS; 119 else if (aInt == bInt) 120 return GE_EQUAL; 121 else 122 return GE_GREATER; 123 } 124} 125 126COMPILER_RT_ALIAS(__getf2, __gttf2) 127 128COMPILER_RT_ABI int __unordtf2(fp_t a, fp_t b) { 129 const rep_t aAbs = toRep(a) & absMask; 130 const rep_t bAbs = toRep(b) & absMask; 131 return aAbs > infRep || bAbs > infRep; 132} 133 134#endif 135