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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