Mercurial > hg > graal-jvmci-8
diff src/share/vm/runtime/atomic.cpp @ 11173:6b0fd0964b87
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 |
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--- a/src/share/vm/runtime/atomic.cpp Tue Jul 30 13:03:28 2013 -0700 +++ b/src/share/vm/runtime/atomic.cpp Wed Jul 31 11:00:54 2013 +0200 @@ -80,3 +80,32 @@ } return old; } + +void Atomic::inc(volatile short* dest) { + // Most platforms do not support atomic increment on a 2-byte value. However, + // if the value occupies the most significant 16 bits of an aligned 32-bit + // word, then we can do this with an atomic add of 0x10000 to the 32-bit word. + // + // The least significant parts of this 32-bit word will never be affected, even + // in case of overflow/underflow. + // + // Use the ATOMIC_SHORT_PAIR macro to get the desired alignment. +#ifdef VM_LITTLE_ENDIAN + assert((intx(dest) & 0x03) == 0x02, "wrong alignment"); + (void)Atomic::add(0x10000, (volatile int*)(dest-1)); +#else + assert((intx(dest) & 0x03) == 0x00, "wrong alignment"); + (void)Atomic::add(0x10000, (volatile int*)(dest)); +#endif +} + +void Atomic::dec(volatile short* dest) { +#ifdef VM_LITTLE_ENDIAN + assert((intx(dest) & 0x03) == 0x02, "wrong alignment"); + (void)Atomic::add(-0x10000, (volatile int*)(dest-1)); +#else + assert((intx(dest) & 0x03) == 0x00, "wrong alignment"); + (void)Atomic::add(-0x10000, (volatile int*)(dest)); +#endif +} +