1// Protocol Buffers - Google's data interchange format
2// Copyright 2012 Google Inc.  All rights reserved.
3// http://code.google.com/p/protobuf/
4//
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6// modification, are permitted provided that the following conditions are
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8//
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18//
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30
31// This file is an internal atomic implementation, use atomicops.h instead.
32
33#ifndef GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_ARM64_GCC_H_
34#define GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_ARM64_GCC_H_
35
36namespace google {
37namespace protobuf {
38namespace internal {
39
40inline void MemoryBarrier() {
41  __asm__ __volatile__ ("dmb ish" ::: "memory");  // NOLINT
42}
43
44// NoBarrier versions of the operation include "memory" in the clobber list.
45// This is not required for direct usage of the NoBarrier versions of the
46// operations. However this is required for correctness when they are used as
47// part of the Acquire or Release versions, to ensure that nothing from outside
48// the call is reordered between the operation and the memory barrier. This does
49// not change the code generated, so has no or minimal impact on the
50// NoBarrier operations.
51
52inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
53                                         Atomic32 old_value,
54                                         Atomic32 new_value) {
55  Atomic32 prev;
56  int32_t temp;
57
58  __asm__ __volatile__ (  // NOLINT
59    "0:                                    \n\t"
60    "ldxr %w[prev], %[ptr]                 \n\t"  // Load the previous value.
61    "cmp %w[prev], %w[old_value]           \n\t"
62    "bne 1f                                \n\t"
63    "stxr %w[temp], %w[new_value], %[ptr]  \n\t"  // Try to store the new value.
64    "cbnz %w[temp], 0b                     \n\t"  // Retry if it did not work.
65    "1:                                    \n\t"
66    : [prev]"=&r" (prev),
67      [temp]"=&r" (temp),
68      [ptr]"+Q" (*ptr)
69    : [old_value]"IJr" (old_value),
70      [new_value]"r" (new_value)
71    : "cc", "memory"
72  );  // NOLINT
73
74  return prev;
75}
76
77inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr,
78                                         Atomic32 new_value) {
79  Atomic32 result;
80  int32_t temp;
81
82  __asm__ __volatile__ (  // NOLINT
83    "0:                                    \n\t"
84    "ldxr %w[result], %[ptr]               \n\t"  // Load the previous value.
85    "stxr %w[temp], %w[new_value], %[ptr]  \n\t"  // Try to store the new value.
86    "cbnz %w[temp], 0b                     \n\t"  // Retry if it did not work.
87    : [result]"=&r" (result),
88      [temp]"=&r" (temp),
89      [ptr]"+Q" (*ptr)
90    : [new_value]"r" (new_value)
91    : "memory"
92  );  // NOLINT
93
94  return result;
95}
96
97inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr,
98                                          Atomic32 increment) {
99  Atomic32 result;
100  int32_t temp;
101
102  __asm__ __volatile__ (  // NOLINT
103    "0:                                       \n\t"
104    "ldxr %w[result], %[ptr]                  \n\t"  // Load the previous value.
105    "add %w[result], %w[result], %w[increment]\n\t"
106    "stxr %w[temp], %w[result], %[ptr]        \n\t"  // Try to store the result.
107    "cbnz %w[temp], 0b                        \n\t"  // Retry on failure.
108    : [result]"=&r" (result),
109      [temp]"=&r" (temp),
110      [ptr]"+Q" (*ptr)
111    : [increment]"IJr" (increment)
112    : "memory"
113  );  // NOLINT
114
115  return result;
116}
117
118inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr,
119                                        Atomic32 increment) {
120  MemoryBarrier();
121  Atomic32 result = NoBarrier_AtomicIncrement(ptr, increment);
122  MemoryBarrier();
123
124  return result;
125}
126
127inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
128                                       Atomic32 old_value,
129                                       Atomic32 new_value) {
130  Atomic32 prev = NoBarrier_CompareAndSwap(ptr, old_value, new_value);
131  MemoryBarrier();
132
133  return prev;
134}
135
136inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
137                                       Atomic32 old_value,
138                                       Atomic32 new_value) {
139  MemoryBarrier();
140  Atomic32 prev = NoBarrier_CompareAndSwap(ptr, old_value, new_value);
141
142  return prev;
143}
144
145inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
146  *ptr = value;
147}
148
149inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) {
150  *ptr = value;
151  MemoryBarrier();
152}
153
154inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
155  __asm__ __volatile__ (  // NOLINT
156    "stlr %w[value], %[ptr]  \n\t"
157    : [ptr]"=Q" (*ptr)
158    : [value]"r" (value)
159    : "memory"
160  );  // NOLINT
161}
162
163inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
164  return *ptr;
165}
166
167inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) {
168  Atomic32 value;
169
170  __asm__ __volatile__ (  // NOLINT
171    "ldar %w[value], %[ptr]  \n\t"
172    : [value]"=r" (value)
173    : [ptr]"Q" (*ptr)
174    : "memory"
175  );  // NOLINT
176
177  return value;
178}
179
180inline Atomic32 Release_Load(volatile const Atomic32* ptr) {
181  MemoryBarrier();
182  return *ptr;
183}
184
185// 64-bit versions of the operations.
186// See the 32-bit versions for comments.
187
188inline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr,
189                                         Atomic64 old_value,
190                                         Atomic64 new_value) {
191  Atomic64 prev;
192  int32_t temp;
193
194  __asm__ __volatile__ (  // NOLINT
195    "0:                                    \n\t"
196    "ldxr %[prev], %[ptr]                  \n\t"
197    "cmp %[prev], %[old_value]             \n\t"
198    "bne 1f                                \n\t"
199    "stxr %w[temp], %[new_value], %[ptr]   \n\t"
200    "cbnz %w[temp], 0b                     \n\t"
201    "1:                                    \n\t"
202    : [prev]"=&r" (prev),
203      [temp]"=&r" (temp),
204      [ptr]"+Q" (*ptr)
205    : [old_value]"IJr" (old_value),
206      [new_value]"r" (new_value)
207    : "cc", "memory"
208  );  // NOLINT
209
210  return prev;
211}
212
213inline Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr,
214                                         Atomic64 new_value) {
215  Atomic64 result;
216  int32_t temp;
217
218  __asm__ __volatile__ (  // NOLINT
219    "0:                                    \n\t"
220    "ldxr %[result], %[ptr]                \n\t"
221    "stxr %w[temp], %[new_value], %[ptr]   \n\t"
222    "cbnz %w[temp], 0b                     \n\t"
223    : [result]"=&r" (result),
224      [temp]"=&r" (temp),
225      [ptr]"+Q" (*ptr)
226    : [new_value]"r" (new_value)
227    : "memory"
228  );  // NOLINT
229
230  return result;
231}
232
233inline Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr,
234                                          Atomic64 increment) {
235  Atomic64 result;
236  int32_t temp;
237
238  __asm__ __volatile__ (  // NOLINT
239    "0:                                     \n\t"
240    "ldxr %[result], %[ptr]                 \n\t"
241    "add %[result], %[result], %[increment] \n\t"
242    "stxr %w[temp], %[result], %[ptr]       \n\t"
243    "cbnz %w[temp], 0b                      \n\t"
244    : [result]"=&r" (result),
245      [temp]"=&r" (temp),
246      [ptr]"+Q" (*ptr)
247    : [increment]"IJr" (increment)
248    : "memory"
249  );  // NOLINT
250
251  return result;
252}
253
254inline Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr,
255                                        Atomic64 increment) {
256  MemoryBarrier();
257  Atomic64 result = NoBarrier_AtomicIncrement(ptr, increment);
258  MemoryBarrier();
259
260  return result;
261}
262
263inline Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr,
264                                       Atomic64 old_value,
265                                       Atomic64 new_value) {
266  Atomic64 prev = NoBarrier_CompareAndSwap(ptr, old_value, new_value);
267  MemoryBarrier();
268
269  return prev;
270}
271
272inline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr,
273                                       Atomic64 old_value,
274                                       Atomic64 new_value) {
275  MemoryBarrier();
276  Atomic64 prev = NoBarrier_CompareAndSwap(ptr, old_value, new_value);
277
278  return prev;
279}
280
281inline void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value) {
282  *ptr = value;
283}
284
285inline void Acquire_Store(volatile Atomic64* ptr, Atomic64 value) {
286  *ptr = value;
287  MemoryBarrier();
288}
289
290inline void Release_Store(volatile Atomic64* ptr, Atomic64 value) {
291  __asm__ __volatile__ (  // NOLINT
292    "stlr %x[value], %[ptr]  \n\t"
293    : [ptr]"=Q" (*ptr)
294    : [value]"r" (value)
295    : "memory"
296  );  // NOLINT
297}
298
299inline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) {
300  return *ptr;
301}
302
303inline Atomic64 Acquire_Load(volatile const Atomic64* ptr) {
304  Atomic64 value;
305
306  __asm__ __volatile__ (  // NOLINT
307    "ldar %x[value], %[ptr]  \n\t"
308    : [value]"=r" (value)
309    : [ptr]"Q" (*ptr)
310    : "memory"
311  );  // NOLINT
312
313  return value;
314}
315
316inline Atomic64 Release_Load(volatile const Atomic64* ptr) {
317  MemoryBarrier();
318  return *ptr;
319}
320
321}  // namespace internal
322}  // namespace protobuf
323}  // namespace google
324
325#endif  // GOOGLE_PROTOBUF_ATOMICOPS_INTERNALS_ARM64_GCC_H_
326