1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
| //===-- comparesf2.S - Implement single-precision soft-float comparisons --===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the following soft-fp_t comparison routines:
//
// __eqsf2 __gesf2 __unordsf2
// __lesf2 __gtsf2
// __ltsf2
// __nesf2
//
// The semantics of the routines grouped in each column are identical, so there
// is a single implementation for each, with multiple names.
//
// The routines behave as follows:
//
// __lesf2(a,b) returns -1 if a < b
// 0 if a == b
// 1 if a > b
// 1 if either a or b is NaN
//
// __gesf2(a,b) returns -1 if a < b
// 0 if a == b
// 1 if a > b
// -1 if either a or b is NaN
//
// __unordsf2(a,b) returns 0 if both a and b are numbers
// 1 if either a or b is NaN
//
// Note that __lesf2( ) and __gesf2( ) are identical except in their handling of
// NaN values.
//
//===----------------------------------------------------------------------===//
#include "../assembly.h"
.syntax unified
.text
DEFINE_CODE_STATE
.macro COMPARESF2_FUNCTION_BODY handle_nan:req
#if defined(COMPILER_RT_ARMHF_TARGET)
vmov r0, s0
vmov r1, s1
#endif
// Make copies of a and b with the sign bit shifted off the top. These will
// be used to detect zeros and NaNs.
#if defined(USE_THUMB_1)
push {r6, lr}
lsls r2, r0, #1
lsls r3, r1, #1
#else
mov r2, r0, lsl #1
mov r3, r1, lsl #1
#endif
// We do the comparison in three stages (ignoring NaN values for the time
// being). First, we orr the absolute values of a and b; this sets the Z
// flag if both a and b are zero (of either sign). The shift of r3 doesn't
// effect this at all, but it *does* make sure that the C flag is clear for
// the subsequent operations.
#if defined(USE_THUMB_1)
lsrs r6, r3, #1
orrs r6, r2
#else
orrs r12, r2, r3, lsr #1
#endif
// Next, we check if a and b have the same or different signs. If they have
// opposite signs, this eor will set the N flag.
#if defined(USE_THUMB_1)
beq 1f
movs r6, r0
eors r6, r1
1:
#else
it ne
eorsne r12, r0, r1
#endif
// If a and b are equal (either both zeros or bit identical; again, we're
// ignoring NaNs for now), this subtract will zero out r0. If they have the
// same sign, the flags are updated as they would be for a comparison of the
// absolute values of a and b.
#if defined(USE_THUMB_1)
bmi 1f
subs r0, r2, r3
1:
#else
it pl
subspl r0, r2, r3
#endif
// If a is smaller in magnitude than b and both have the same sign, place
// the negation of the sign of b in r0. Thus, if both are negative and
// a > b, this sets r0 to 0; if both are positive and a < b, this sets
// r0 to -1.
//
// This is also done if a and b have opposite signs and are not both zero,
// because in that case the subtract was not performed and the C flag is
// still clear from the shift argument in orrs; if a is positive and b
// negative, this places 0 in r0; if a is negative and b positive, -1 is
// placed in r0.
#if defined(USE_THUMB_1)
bhs 1f
// Here if a and b have the same sign and absA < absB, the result is thus
// b < 0 ? 1 : -1. Same if a and b have the opposite sign (ignoring Nan).
movs r0, #1
lsrs r1, #31
bne LOCAL_LABEL(CHECK_NAN\@)
negs r0, r0
b LOCAL_LABEL(CHECK_NAN\@)
1:
#else
it lo
mvnlo r0, r1, asr #31
#endif
// If a is greater in magnitude than b and both have the same sign, place
// the sign of b in r0. Thus, if both are negative and a < b, -1 is placed
// in r0, which is the desired result. Conversely, if both are positive
// and a > b, zero is placed in r0.
#if defined(USE_THUMB_1)
bls 1f
// Here both have the same sign and absA > absB.
movs r0, #1
lsrs r1, #31
beq LOCAL_LABEL(CHECK_NAN\@)
negs r0, r0
1:
#else
it hi
movhi r0, r1, asr #31
#endif
// If you've been keeping track, at this point r0 contains -1 if a < b and
// 0 if a >= b. All that remains to be done is to set it to 1 if a > b.
// If a == b, then the Z flag is set, so we can get the correct final value
// into r0 by simply or'ing with 1 if Z is clear.
// For Thumb-1, r0 contains -1 if a < b, 0 if a > b and 0 if a == b.
#if !defined(USE_THUMB_1)
it ne
orrne r0, r0, #1
#endif
// Finally, we need to deal with NaNs. If either argument is NaN, replace
// the value in r0 with 1.
#if defined(USE_THUMB_1)
LOCAL_LABEL(CHECK_NAN\@):
movs r6, #0xff
lsls r6, #24
cmp r2, r6
bhi 1f
cmp r3, r6
1:
bls 2f
\handle_nan
2:
pop {r6, pc}
#else
cmp r2, #0xff000000
ite ls
cmpls r3, #0xff000000
\handle_nan
JMP(lr)
#endif
.endm
@ int __eqsf2(float a, float b)
.p2align 2
DEFINE_COMPILERRT_FUNCTION(__eqsf2)
.macro __eqsf2_handle_nan
#if defined(USE_THUMB_1)
movs r0, #1
#else
movhi r0, #1
#endif
.endm
COMPARESF2_FUNCTION_BODY __eqsf2_handle_nan
END_COMPILERRT_FUNCTION(__eqsf2)
DEFINE_COMPILERRT_FUNCTION_ALIAS(__lesf2, __eqsf2)
DEFINE_COMPILERRT_FUNCTION_ALIAS(__ltsf2, __eqsf2)
DEFINE_COMPILERRT_FUNCTION_ALIAS(__nesf2, __eqsf2)
#if defined(__ELF__)
// Alias for libgcc compatibility
DEFINE_COMPILERRT_FUNCTION_ALIAS(__cmpsf2, __lesf2)
#endif
@ int __gtsf2(float a, float b)
.p2align 2
DEFINE_COMPILERRT_FUNCTION(__gtsf2)
.macro __gtsf2_handle_nan
#if defined(USE_THUMB_1)
movs r0, #1
negs r0, r0
#else
movhi r0, #-1
#endif
.endm
COMPARESF2_FUNCTION_BODY __gtsf2_handle_nan
END_COMPILERRT_FUNCTION(__gtsf2)
DEFINE_COMPILERRT_FUNCTION_ALIAS(__gesf2, __gtsf2)
@ int __unordsf2(float a, float b)
.p2align 2
DEFINE_COMPILERRT_FUNCTION(__unordsf2)
#if defined(COMPILER_RT_ARMHF_TARGET)
vmov r0, s0
vmov r1, s1
#endif
// Return 1 for NaN values, 0 otherwise.
lsls r2, r0, #1
lsls r3, r1, #1
movs r0, #0
#if defined(USE_THUMB_1)
movs r1, #0xff
lsls r1, #24
cmp r2, r1
bhi 1f
cmp r3, r1
1:
bls 2f
movs r0, #1
2:
#else
cmp r2, #0xff000000
ite ls
cmpls r3, #0xff000000
movhi r0, #1
#endif
JMP(lr)
END_COMPILERRT_FUNCTION(__unordsf2)
#if defined(COMPILER_RT_ARMHF_TARGET)
DEFINE_COMPILERRT_FUNCTION(__aeabi_fcmpun)
vmov s0, r0
vmov s1, r1
b SYMBOL_NAME(__unordsf2)
END_COMPILERRT_FUNCTION(__aeabi_fcmpun)
#else
DEFINE_AEABI_FUNCTION_ALIAS(__aeabi_fcmpun, __unordsf2)
#endif
NO_EXEC_STACK_DIRECTIVE
|