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
__letf2(fp_t a,fp_t b)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 #if defined(__ELF__)
83 // Alias for libgcc compatibility
84 FNALIAS(__cmptf2, __letf2);
85 #endif
86
87 enum GE_RESULT {
88 GE_LESS = -1,
89 GE_EQUAL = 0,
90 GE_GREATER = 1,
91 GE_UNORDERED = -1 // Note: different from LE_UNORDERED
92 };
93
__getf2(fp_t a,fp_t b)94 COMPILER_RT_ABI enum GE_RESULT __getf2(fp_t a, fp_t b) {
95
96 const srep_t aInt = toRep(a);
97 const srep_t bInt = toRep(b);
98 const rep_t aAbs = aInt & absMask;
99 const rep_t bAbs = bInt & absMask;
100
101 if (aAbs > infRep || bAbs > infRep) return GE_UNORDERED;
102 if ((aAbs | bAbs) == 0) return GE_EQUAL;
103 if ((aInt & bInt) >= 0) {
104 if (aInt < bInt) return GE_LESS;
105 else if (aInt == bInt) return GE_EQUAL;
106 else return GE_GREATER;
107 } else {
108 if (aInt > bInt) return GE_LESS;
109 else if (aInt == bInt) return GE_EQUAL;
110 else return GE_GREATER;
111 }
112 }
113
__unordtf2(fp_t a,fp_t b)114 COMPILER_RT_ABI int __unordtf2(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
__eqtf2(fp_t a,fp_t b)122 COMPILER_RT_ABI enum LE_RESULT __eqtf2(fp_t a, fp_t b) {
123 return __letf2(a, b);
124 }
125
__lttf2(fp_t a,fp_t b)126 COMPILER_RT_ABI enum LE_RESULT __lttf2(fp_t a, fp_t b) {
127 return __letf2(a, b);
128 }
129
__netf2(fp_t a,fp_t b)130 COMPILER_RT_ABI enum LE_RESULT __netf2(fp_t a, fp_t b) {
131 return __letf2(a, b);
132 }
133
__gttf2(fp_t a,fp_t b)134 COMPILER_RT_ABI enum GE_RESULT __gttf2(fp_t a, fp_t b) {
135 return __getf2(a, b);
136 }
137
138 #endif
139