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)
44enum LE_RESULT {
45    LE_LESS      = -1,
46    LE_EQUAL     =  0,
47    LE_GREATER   =  1,
48    LE_UNORDERED =  1
49};
50
51COMPILER_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
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
89COMPILER_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
109COMPILER_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
117COMPILER_RT_ABI enum LE_RESULT __eqtf2(fp_t a, fp_t b) {
118    return __letf2(a, b);
119}
120
121COMPILER_RT_ABI enum LE_RESULT __lttf2(fp_t a, fp_t b) {
122    return __letf2(a, b);
123}
124
125COMPILER_RT_ABI enum LE_RESULT __netf2(fp_t a, fp_t b) {
126    return __letf2(a, b);
127}
128
129COMPILER_RT_ABI enum GE_RESULT __gttf2(fp_t a, fp_t b) {
130    return __getf2(a, b);
131}
132
133#endif
134