Stephen Hines | 2d1fdb2 | 2014-05-28 23:58:16 -0700 | [diff] [blame] | 1 | //===-- lib/comparetf2.c - Quad-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 | // __eqtf2 __getf2 __unordtf2 |
| 13 | // __letf2 __gttf2 |
| 14 | // __lttf2 |
| 15 | // __netf2 |
| 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 | // __letf2(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 | // __getf2(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 | // __unordtf2(a,b) returns 0 if both a and b are numbers |
| 33 | // 1 if either a or b is NaN |
| 34 | // |
| 35 | // Note that __letf2( ) and __getf2( ) are identical except in their handling of |
| 36 | // NaN values. |
| 37 | // |
| 38 | //===----------------------------------------------------------------------===// |
| 39 | |
| 40 | #define QUAD_PRECISION |
| 41 | #include "fp_lib.h" |
| 42 | |
| 43 | #if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT) |
| 44 | enum LE_RESULT { |
| 45 | LE_LESS = -1, |
| 46 | LE_EQUAL = 0, |
| 47 | LE_GREATER = 1, |
| 48 | LE_UNORDERED = 1 |
| 49 | }; |
| 50 | |
| 51 | COMPILER_RT_ABI enum LE_RESULT __letf2(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 | else { |
| 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 | if (aInt > bInt) return LE_LESS; |
| 77 | else if (aInt == bInt) return LE_EQUAL; |
| 78 | else return LE_GREATER; |
| 79 | } |
| 80 | } |
| 81 | |
| 82 | enum 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 | |
| 89 | COMPILER_RT_ABI enum GE_RESULT __getf2(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 | |
| 109 | COMPILER_RT_ABI int __unordtf2(fp_t a, fp_t b) { |
| 110 | const rep_t aAbs = toRep(a) & absMask; |
| 111 | const rep_t bAbs = toRep(b) & absMask; |
| 112 | return aAbs > infRep || bAbs > infRep; |
| 113 | } |
| 114 | |
| 115 | // The following are alternative names for the preceding routines. |
| 116 | |
| 117 | COMPILER_RT_ABI enum LE_RESULT __eqtf2(fp_t a, fp_t b) { |
| 118 | return __letf2(a, b); |
| 119 | } |
| 120 | |
| 121 | COMPILER_RT_ABI enum LE_RESULT __lttf2(fp_t a, fp_t b) { |
| 122 | return __letf2(a, b); |
| 123 | } |
| 124 | |
| 125 | COMPILER_RT_ABI enum LE_RESULT __netf2(fp_t a, fp_t b) { |
| 126 | return __letf2(a, b); |
| 127 | } |
| 128 | |
| 129 | COMPILER_RT_ABI enum GE_RESULT __gttf2(fp_t a, fp_t b) { |
| 130 | return __getf2(a, b); |
| 131 | } |
| 132 | |
| 133 | #endif |