1 //===-- lib/comparedf2.c - Double-precision comparisons -----------*- C -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // // This file implements the following soft-float comparison routines: 11 // 12 // __eqdf2 __gedf2 __unorddf2 13 // __ledf2 __gtdf2 14 // __ltdf2 15 // __nedf2 16 // 17 // The semantics of the routines grouped in each column are identical, so there 18 // is a single implementation for each, and wrappers to provide the other names. 19 // 20 // The main routines behave as follows: 21 // 22 // __ledf2(a,b) returns -1 if a < b 23 // 0 if a == b 24 // 1 if a > b 25 // 1 if either a or b is NaN 26 // 27 // __gedf2(a,b) returns -1 if a < b 28 // 0 if a == b 29 // 1 if a > b 30 // -1 if either a or b is NaN 31 // 32 // __unorddf2(a,b) returns 0 if both a and b are numbers 33 // 1 if either a or b is NaN 34 // 35 // Note that __ledf2( ) and __gedf2( ) are identical except in their handling of 36 // NaN values. 37 // 38 //===----------------------------------------------------------------------===// 39 40 #define DOUBLE_PRECISION 41 #include "fp_lib.h" 42 43 enum LE_RESULT { 44 LE_LESS = -1, 45 LE_EQUAL = 0, 46 LE_GREATER = 1, 47 LE_UNORDERED = 1 48 }; 49 50 COMPILER_RT_ABI enum LE_RESULT 51 __ledf2(fp_t a, fp_t b) { 52 53 const srep_t aInt = toRep(a); 54 const srep_t bInt = toRep(b); 55 const rep_t aAbs = aInt & absMask; 56 const rep_t bAbs = bInt & absMask; 57 58 // If either a or b is NaN, they are unordered. 59 if (aAbs > infRep || bAbs > infRep) return LE_UNORDERED; 60 61 // If a and b are both zeros, they are equal. 62 if ((aAbs | bAbs) == 0) return LE_EQUAL; 63 64 // If at least one of a and b is positive, we get the same result comparing 65 // a and b as signed integers as we would with a floating-point compare. 66 if ((aInt & bInt) >= 0) { 67 if (aInt < bInt) return LE_LESS; 68 else if (aInt == bInt) return LE_EQUAL; 69 else return LE_GREATER; 70 } 71 72 // Otherwise, both are negative, so we need to flip the sense of the 73 // comparison to get the correct result. (This assumes a twos- or ones- 74 // complement integer representation; if integers are represented in a 75 // sign-magnitude representation, then this flip is incorrect). 76 else { 77 if (aInt > bInt) return LE_LESS; 78 else if (aInt == bInt) return LE_EQUAL; 79 else return LE_GREATER; 80 } 81 } 82 83 enum GE_RESULT { 84 GE_LESS = -1, 85 GE_EQUAL = 0, 86 GE_GREATER = 1, 87 GE_UNORDERED = -1 // Note: different from LE_UNORDERED 88 }; 89 90 COMPILER_RT_ABI enum GE_RESULT 91 __gedf2(fp_t a, fp_t b) { 92 93 const srep_t aInt = toRep(a); 94 const srep_t bInt = toRep(b); 95 const rep_t aAbs = aInt & absMask; 96 const rep_t bAbs = bInt & absMask; 97 98 if (aAbs > infRep || bAbs > infRep) return GE_UNORDERED; 99 if ((aAbs | bAbs) == 0) return GE_EQUAL; 100 if ((aInt & bInt) >= 0) { 101 if (aInt < bInt) return GE_LESS; 102 else if (aInt == bInt) return GE_EQUAL; 103 else return GE_GREATER; 104 } else { 105 if (aInt > bInt) return GE_LESS; 106 else if (aInt == bInt) return GE_EQUAL; 107 else return GE_GREATER; 108 } 109 } 110 111 ARM_EABI_FNALIAS(dcmpun, unorddf2) 112 113 COMPILER_RT_ABI int 114 __unorddf2(fp_t a, fp_t b) { 115 const rep_t aAbs = toRep(a) & absMask; 116 const rep_t bAbs = toRep(b) & absMask; 117 return aAbs > infRep || bAbs > infRep; 118 } 119 120 // The following are alternative names for the preceding routines. 121 122 COMPILER_RT_ABI enum LE_RESULT 123 __eqdf2(fp_t a, fp_t b) { 124 return __ledf2(a, b); 125 } 126 127 COMPILER_RT_ABI enum LE_RESULT 128 __ltdf2(fp_t a, fp_t b) { 129 return __ledf2(a, b); 130 } 131 132 COMPILER_RT_ABI enum LE_RESULT 133 __nedf2(fp_t a, fp_t b) { 134 return __ledf2(a, b); 135 } 136 137 COMPILER_RT_ABI enum GE_RESULT 138 __gtdf2(fp_t a, fp_t b) { 139 return __gedf2(a, b); 140 } 141 142
