1 //===-- lib/comparedf2.c - Double-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 // __eqdf2 __gedf2 __unorddf2 12 // __ledf2 __gtdf2 13 // __ltdf2 14 // __nedf2 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 // __ledf2(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 // __gedf2(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 // __unorddf2(a,b) returns 0 if both a and b are numbers 32 // 1 if either a or b is NaN 33 // 34 // Note that __ledf2( ) and __gedf2( ) are identical except in their handling of 35 // NaN values. 36 // 37 //===----------------------------------------------------------------------===// 38 39 #define DOUBLE_PRECISION 40 #include "fp_lib.h" 41 42 enum LE_RESULT { LE_LESS = -1, LE_EQUAL = 0, LE_GREATER = 1, LE_UNORDERED = 1 }; 43 44 COMPILER_RT_ABI enum LE_RESULT __ledf2(fp_t a, fp_t b) { 45 46 const srep_t aInt = toRep(a); 47 const srep_t bInt = toRep(b); 48 const rep_t aAbs = aInt & absMask; 49 const rep_t bAbs = bInt & absMask; 50 51 // If either a or b is NaN, they are unordered. 52 if (aAbs > infRep || bAbs > infRep) 53 return LE_UNORDERED; 54 55 // If a and b are both zeros, they are equal. 56 if ((aAbs | bAbs) == 0) 57 return LE_EQUAL; 58 59 // If at least one of a and b is positive, we get the same result comparing 60 // a and b as signed integers as we would with a floating-point compare. 61 if ((aInt & bInt) >= 0) { 62 if (aInt < bInt) 63 return LE_LESS; 64 else if (aInt == bInt) 65 return LE_EQUAL; 66 else 67 return LE_GREATER; 68 } 69 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 else { 75 if (aInt > bInt) 76 return LE_LESS; 77 else if (aInt == bInt) 78 return LE_EQUAL; 79 else 80 return LE_GREATER; 81 } 82 } 83 84 #if defined(__ELF__) 85 // Alias for libgcc compatibility 86 COMPILER_RT_ALIAS(__ledf2, __cmpdf2) 87 #endif 88 COMPILER_RT_ALIAS(__ledf2, __eqdf2) 89 COMPILER_RT_ALIAS(__ledf2, __ltdf2) 90 COMPILER_RT_ALIAS(__ledf2, __nedf2) 91 92 enum GE_RESULT { 93 GE_LESS = -1, 94 GE_EQUAL = 0, 95 GE_GREATER = 1, 96 GE_UNORDERED = -1 // Note: different from LE_UNORDERED 97 }; 98 99 COMPILER_RT_ABI enum GE_RESULT __gedf2(fp_t a, fp_t b) { 100 101 const srep_t aInt = toRep(a); 102 const srep_t bInt = toRep(b); 103 const rep_t aAbs = aInt & absMask; 104 const rep_t bAbs = bInt & absMask; 105 106 if (aAbs > infRep || bAbs > infRep) 107 return GE_UNORDERED; 108 if ((aAbs | bAbs) == 0) 109 return GE_EQUAL; 110 if ((aInt & bInt) >= 0) { 111 if (aInt < bInt) 112 return GE_LESS; 113 else if (aInt == bInt) 114 return GE_EQUAL; 115 else 116 return GE_GREATER; 117 } else { 118 if (aInt > bInt) 119 return GE_LESS; 120 else if (aInt == bInt) 121 return GE_EQUAL; 122 else 123 return GE_GREATER; 124 } 125 } 126 127 COMPILER_RT_ALIAS(__gedf2, __gtdf2) 128 129 COMPILER_RT_ABI int 130 __unorddf2(fp_t a, fp_t b) { 131 const rep_t aAbs = toRep(a) & absMask; 132 const rep_t bAbs = toRep(b) & absMask; 133 return aAbs > infRep || bAbs > infRep; 134 } 135 136 #if defined(__ARM_EABI__) 137 #if defined(COMPILER_RT_ARMHF_TARGET) 138 AEABI_RTABI int __aeabi_dcmpun(fp_t a, fp_t b) { return __unorddf2(a, b); } 139 #else 140 COMPILER_RT_ALIAS(__unorddf2, __aeabi_dcmpun) 141 #endif 142 #endif 143 144 #if defined(_WIN32) && !defined(__MINGW32__) 145 // The alias mechanism doesn't work on Windows except for MinGW, so emit 146 // wrapper functions. 147 int __eqdf2(fp_t a, fp_t b) { return __ledf2(a, b); } 148 int __ltdf2(fp_t a, fp_t b) { return __ledf2(a, b); } 149 int __nedf2(fp_t a, fp_t b) { return __ledf2(a, b); } 150 int __gtdf2(fp_t a, fp_t b) { return __gedf2(a, b); } 151 #endif 152