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 43enum LE_RESULT { 44 LE_LESS = -1, 45 LE_EQUAL = 0, 46 LE_GREATER = 1, 47 LE_UNORDERED = 1 48}; 49 50enum LE_RESULT __ledf2(fp_t a, fp_t b) { 51 52 const srep_t aInt = toRep(a); 53 const srep_t bInt = toRep(b); 54 const rep_t aAbs = aInt & absMask; 55 const rep_t bAbs = bInt & absMask; 56 57 // If either a or b is NaN, they are unordered. 58 if (aAbs > infRep || bAbs > infRep) return LE_UNORDERED; 59 60 // If a and b are both zeros, they are equal. 61 if ((aAbs | bAbs) == 0) return LE_EQUAL; 62 63 // If at least one of a and b is positive, we get the same result comparing 64 // a and b as signed integers as we would with a floating-point compare. 65 if ((aInt & bInt) >= 0) { 66 if (aInt < bInt) return LE_LESS; 67 else if (aInt == bInt) return LE_EQUAL; 68 else return LE_GREATER; 69 } 70 71 // Otherwise, both are negative, so we need to flip the sense of the 72 // comparison to get the correct result. (This assumes a twos- or ones- 73 // complement integer representation; if integers are represented in a 74 // sign-magnitude representation, then this flip is incorrect). 75 else { 76 if (aInt > bInt) return LE_LESS; 77 else if (aInt == bInt) return LE_EQUAL; 78 else return LE_GREATER; 79 } 80} 81 82enum GE_RESULT { 83 GE_LESS = -1, 84 GE_EQUAL = 0, 85 GE_GREATER = 1, 86 GE_UNORDERED = -1 // Note: different from LE_UNORDERED 87}; 88 89enum GE_RESULT __gedf2(fp_t a, fp_t b) { 90 91 const srep_t aInt = toRep(a); 92 const srep_t bInt = toRep(b); 93 const rep_t aAbs = aInt & absMask; 94 const rep_t bAbs = bInt & absMask; 95 96 if (aAbs > infRep || bAbs > infRep) return GE_UNORDERED; 97 if ((aAbs | bAbs) == 0) return GE_EQUAL; 98 if ((aInt & bInt) >= 0) { 99 if (aInt < bInt) return GE_LESS; 100 else if (aInt == bInt) return GE_EQUAL; 101 else return GE_GREATER; 102 } else { 103 if (aInt > bInt) return GE_LESS; 104 else if (aInt == bInt) return GE_EQUAL; 105 else return GE_GREATER; 106 } 107} 108 109ARM_EABI_FNALIAS(dcmpun, unorddf2) 110 111int __unorddf2(fp_t a, fp_t b) { 112 const rep_t aAbs = toRep(a) & absMask; 113 const rep_t bAbs = toRep(b) & absMask; 114 return aAbs > infRep || bAbs > infRep; 115} 116 117// The following are alternative names for the preceeding routines. 118 119enum LE_RESULT __eqdf2(fp_t a, fp_t b) { 120 return __ledf2(a, b); 121} 122 123enum LE_RESULT __ltdf2(fp_t a, fp_t b) { 124 return __ledf2(a, b); 125} 126 127enum LE_RESULT __nedf2(fp_t a, fp_t b) { 128 return __ledf2(a, b); 129} 130 131enum GE_RESULT __gtdf2(fp_t a, fp_t b) { 132 return __gedf2(a, b); 133} 134 135