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comparison src/share/vm/runtime/atomic.cpp @ 11173:6b0fd0964b87

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Merge with http://hg.openjdk.java.net/hsx/hsx25/hotspot/
author Doug Simon <doug.simon@oracle.com>
date Wed, 31 Jul 2013 11:00:54 +0200
parents d9eed26d638a
children de6a9e811145 bdd155477289
comparison
equal deleted inserted replaced
10912:4ea54634f03e 11173:6b0fd0964b87
78 old = load(dest); 78 old = load(dest);
79 new_value = old + add_value; 79 new_value = old + add_value;
80 } 80 }
81 return old; 81 return old;
82 } 82 }
83
84 void Atomic::inc(volatile short* dest) {
85 // Most platforms do not support atomic increment on a 2-byte value. However,
86 // if the value occupies the most significant 16 bits of an aligned 32-bit
87 // word, then we can do this with an atomic add of 0x10000 to the 32-bit word.
88 //
89 // The least significant parts of this 32-bit word will never be affected, even
90 // in case of overflow/underflow.
91 //
92 // Use the ATOMIC_SHORT_PAIR macro to get the desired alignment.
93 #ifdef VM_LITTLE_ENDIAN
94 assert((intx(dest) & 0x03) == 0x02, "wrong alignment");
95 (void)Atomic::add(0x10000, (volatile int*)(dest-1));
96 #else
97 assert((intx(dest) & 0x03) == 0x00, "wrong alignment");
98 (void)Atomic::add(0x10000, (volatile int*)(dest));
99 #endif
100 }
101
102 void Atomic::dec(volatile short* dest) {
103 #ifdef VM_LITTLE_ENDIAN
104 assert((intx(dest) & 0x03) == 0x02, "wrong alignment");
105 (void)Atomic::add(-0x10000, (volatile int*)(dest-1));
106 #else
107 assert((intx(dest) & 0x03) == 0x00, "wrong alignment");
108 (void)Atomic::add(-0x10000, (volatile int*)(dest));
109 #endif
110 }
111