[arm64] Use exclusive instructions in exchange

src/arm64/constants-arm64.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ARM64_CONSTANTS_ARM64_H_
 #define V8_ARM64_CONSTANTS_ARM64_H_
 
 #include "src/base/macros.h"
 #include "src/globals.h"
 
@@ skipping 846 matching lines @@
   LoadStoreRegisterOffsetFixed = 0x38200800,
   LoadStoreRegisterOffsetFMask = 0x3B200C00,
   LoadStoreRegisterOffsetMask  = 0xFFE00C00,
   PRFM_reg                     = LoadStoreRegisterOffsetFixed | PRFM,
   #define LOAD_STORE_REGISTER_OFFSET(A, B, C, D) \
   A##B##_##C##_reg = LoadStoreRegisterOffsetFixed | D
   LOAD_STORE_OP_LIST(LOAD_STORE_REGISTER_OFFSET)
   #undef LOAD_STORE_REGISTER_OFFSET
 };
 
-// Load/store acquire/release
+// Load/store acquire/release.
 enum LoadStoreAcquireReleaseOp {
   LoadStoreAcquireReleaseFixed = 0x08000000,
   LoadStoreAcquireReleaseFMask = 0x3F000000,
   LoadStoreAcquireReleaseMask = 0xCFC08000,
   STLXR_b = LoadStoreAcquireReleaseFixed | 0x00008000,
   LDAXR_b = LoadStoreAcquireReleaseFixed | 0x00408000,
   STLR_b  = LoadStoreAcquireReleaseFixed | 0x00808000,
   LDAR_b  = LoadStoreAcquireReleaseFixed | 0x00C08000,
   STLXR_h = LoadStoreAcquireReleaseFixed | 0x40008000,
   LDAXR_h = LoadStoreAcquireReleaseFixed | 0x40408000,
   STLR_h  = LoadStoreAcquireReleaseFixed | 0x40808000,
   LDAR_h  = LoadStoreAcquireReleaseFixed | 0x40C08000,
   STLXR_w = LoadStoreAcquireReleaseFixed | 0x80008000,
   LDAXR_w = LoadStoreAcquireReleaseFixed | 0x80408000,
   STLR_w  = LoadStoreAcquireReleaseFixed | 0x80808000,
   LDAR_w  = LoadStoreAcquireReleaseFixed | 0x80C08000,
   STLXR_x = LoadStoreAcquireReleaseFixed | 0xC0008000,
   LDAXR_x = LoadStoreAcquireReleaseFixed | 0xC0408000,
   STLR_x  = LoadStoreAcquireReleaseFixed | 0xC0808000,
   LDAR_x  = LoadStoreAcquireReleaseFixed | 0xC0C08000,
 };
 
+// Load/store exclusive.
+enum LoadStoreExclusiveOp {
+  LoadStoreExclusiveFixed = 0x08000000,
+  LoadStoreExclusiveFMask = 0x3F808000,
+  LoadStoreExclusiveMask = 0xFFE08000,
+  STXRB = LoadStoreExclusiveFixed,
+  LDXRB = LoadStoreExclusiveFixed | 0x00400000,
+  STXRH = LoadStoreExclusiveFixed | 0x40000000,
+  LDXRH = LoadStoreExclusiveFixed | 0x40400000,
+  STXR_w = LoadStoreExclusiveFixed | 0x80000000,
+  LDXR_w = LoadStoreExclusiveFixed | 0x80400000,
+  STXR_x = LoadStoreExclusiveFixed | 0xC0000000,
+  LDXR_x = LoadStoreExclusiveFixed | 0xC0400000,
+};
+
 // Conditional compare.
 enum ConditionalCompareOp {
   ConditionalCompareMask = 0x60000000,
   CCMN                   = 0x20000000,
   CCMP                   = 0x60000000
 };
 
 // Conditional compare register.
 enum ConditionalCompareRegisterOp {
   ConditionalCompareRegisterFixed = 0x1A400000,
@@ skipping 357 matching lines @@
 
 enum UnallocatedOp {
   UnallocatedFixed = 0x00000000,
   UnallocatedFMask = 0x00000000
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ARM64_CONSTANTS_ARM64_H_