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
__ledf2(fp_t a,fp_t b)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 #if defined(__ELF__)
84 // Alias for libgcc compatibility
85 FNALIAS(__cmpdf2, __ledf2);
86 #endif
87
88 enum GE_RESULT {
89 GE_LESS = -1,
90 GE_EQUAL = 0,
91 GE_GREATER = 1,
92 GE_UNORDERED = -1 // Note: different from LE_UNORDERED
93 };
94
95 COMPILER_RT_ABI enum GE_RESULT
__gedf2(fp_t a,fp_t b)96 __gedf2(fp_t a, fp_t b) {
97
98 const srep_t aInt = toRep(a);
99 const srep_t bInt = toRep(b);
100 const rep_t aAbs = aInt & absMask;
101 const rep_t bAbs = bInt & absMask;
102
103 if (aAbs > infRep || bAbs > infRep) return GE_UNORDERED;
104 if ((aAbs | bAbs) == 0) return GE_EQUAL;
105 if ((aInt & bInt) >= 0) {
106 if (aInt < bInt) return GE_LESS;
107 else if (aInt == bInt) return GE_EQUAL;
108 else return GE_GREATER;
109 } else {
110 if (aInt > bInt) return GE_LESS;
111 else if (aInt == bInt) return GE_EQUAL;
112 else return GE_GREATER;
113 }
114 }
115
ARM_EABI_FNALIAS(dcmpun,unorddf2)116 ARM_EABI_FNALIAS(dcmpun, unorddf2)
117
118 COMPILER_RT_ABI int
119 __unorddf2(fp_t a, fp_t b) {
120 const rep_t aAbs = toRep(a) & absMask;
121 const rep_t bAbs = toRep(b) & absMask;
122 return aAbs > infRep || bAbs > infRep;
123 }
124
125 // The following are alternative names for the preceding routines.
126
127 COMPILER_RT_ABI enum LE_RESULT
__eqdf2(fp_t a,fp_t b)128 __eqdf2(fp_t a, fp_t b) {
129 return __ledf2(a, b);
130 }
131
132 COMPILER_RT_ABI enum LE_RESULT
__ltdf2(fp_t a,fp_t b)133 __ltdf2(fp_t a, fp_t b) {
134 return __ledf2(a, b);
135 }
136
137 COMPILER_RT_ABI enum LE_RESULT
__nedf2(fp_t a,fp_t b)138 __nedf2(fp_t a, fp_t b) {
139 return __ledf2(a, b);
140 }
141
142 COMPILER_RT_ABI enum GE_RESULT
__gtdf2(fp_t a,fp_t b)143 __gtdf2(fp_t a, fp_t b) {
144 return __gedf2(a, b);
145 }
146
147