1//===-- lib/comparesf2.c - Single-precision comparisons -----------*- C -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the following soft-fp_t comparison routines:
10//
11//   __eqsf2   __gesf2   __unordsf2
12//   __lesf2   __gtsf2
13//   __ltsf2
14//   __nesf2
15//
16// The semantics of the routines grouped in each column are identical, so there
17// is a single implementation for each, and wrappers to provide the other names.
18//
19// The main routines behave as follows:
20//
21//   __lesf2(a,b) returns -1 if a < b
22//                         0 if a == b
23//                         1 if a > b
24//                         1 if either a or b is NaN
25//
26//   __gesf2(a,b) returns -1 if a < b
27//                         0 if a == b
28//                         1 if a > b
29//                        -1 if either a or b is NaN
30//
31//   __unordsf2(a,b) returns 0 if both a and b are numbers
32//                           1 if either a or b is NaN
33//
34// Note that __lesf2( ) and __gesf2( ) are identical except in their handling of
35// NaN values.
36//
37//===----------------------------------------------------------------------===//
38
39#define SINGLE_PRECISION
40#include "fp_lib.h"
41
42enum LE_RESULT { LE_LESS = -1, LE_EQUAL = 0, LE_GREATER = 1, LE_UNORDERED = 1 };
43
44COMPILER_RT_ABI enum LE_RESULT __lesf2(fp_t a, fp_t b) {
45
46  const srep_t aInt = toRep(a);
47  const srep_t bInt = toRep(b);
48  const rep_t aAbs = aInt & absMask;
49  const rep_t bAbs = bInt & absMask;
50
51  // If either a or b is NaN, they are unordered.
52  if (aAbs > infRep || bAbs > infRep)
53    return LE_UNORDERED;
54
55  // If a and b are both zeros, they are equal.
56  if ((aAbs | bAbs) == 0)
57    return LE_EQUAL;
58
59  // If at least one of a and b is positive, we get the same result comparing
60  // a and b as signed integers as we would with a fp_ting-point compare.
61  if ((aInt & bInt) >= 0) {
62    if (aInt < bInt)
63      return LE_LESS;
64    else if (aInt == bInt)
65      return LE_EQUAL;
66    else
67      return LE_GREATER;
68  }
69
70  // Otherwise, both are negative, so we need to flip the sense of the
71  // comparison to get the correct result.  (This assumes a twos- or ones-
72  // complement integer representation; if integers are represented in a
73  // sign-magnitude representation, then this flip is incorrect).
74  else {
75    if (aInt > bInt)
76      return LE_LESS;
77    else if (aInt == bInt)
78      return LE_EQUAL;
79    else
80      return LE_GREATER;
81  }
82}
83
84#if defined(__ELF__)
85// Alias for libgcc compatibility
86COMPILER_RT_ALIAS(__lesf2, __cmpsf2)
87#endif
88COMPILER_RT_ALIAS(__lesf2, __eqsf2)
89COMPILER_RT_ALIAS(__lesf2, __ltsf2)
90COMPILER_RT_ALIAS(__lesf2, __nesf2)
91
92enum GE_RESULT {
93  GE_LESS = -1,
94  GE_EQUAL = 0,
95  GE_GREATER = 1,
96  GE_UNORDERED = -1 // Note: different from LE_UNORDERED
97};
98
99COMPILER_RT_ABI enum GE_RESULT __gesf2(fp_t a, fp_t b) {
100
101  const srep_t aInt = toRep(a);
102  const srep_t bInt = toRep(b);
103  const rep_t aAbs = aInt & absMask;
104  const rep_t bAbs = bInt & absMask;
105
106  if (aAbs > infRep || bAbs > infRep)
107    return GE_UNORDERED;
108  if ((aAbs | bAbs) == 0)
109    return GE_EQUAL;
110  if ((aInt & bInt) >= 0) {
111    if (aInt < bInt)
112      return GE_LESS;
113    else if (aInt == bInt)
114      return GE_EQUAL;
115    else
116      return GE_GREATER;
117  } else {
118    if (aInt > bInt)
119      return GE_LESS;
120    else if (aInt == bInt)
121      return GE_EQUAL;
122    else
123      return GE_GREATER;
124  }
125}
126
127COMPILER_RT_ALIAS(__gesf2, __gtsf2)
128
129COMPILER_RT_ABI int
130__unordsf2(fp_t a, fp_t b) {
131    const rep_t aAbs = toRep(a) & absMask;
132    const rep_t bAbs = toRep(b) & absMask;
133    return aAbs > infRep || bAbs > infRep;
134}
135
136#if defined(__ARM_EABI__)
137#if defined(COMPILER_RT_ARMHF_TARGET)
138AEABI_RTABI int __aeabi_fcmpun(fp_t a, fp_t b) { return __unordsf2(a, b); }
139#else
140COMPILER_RT_ALIAS(__unordsf2, __aeabi_fcmpun)
141#endif
142#endif
143
144#if defined(_WIN32) && !defined(__MINGW32__)
145// The alias mechanism doesn't work on Windows except for MinGW, so emit
146// wrapper functions.
147int __eqsf2(fp_t a, fp_t b) { return __lesf2(a, b); }
148int __ltsf2(fp_t a, fp_t b) { return __lesf2(a, b); }
149int __nesf2(fp_t a, fp_t b) { return __lesf2(a, b); }
150int __gtsf2(fp_t a, fp_t b) { return __gesf2(a, b); }
151#endif
152