greenplumn arch-ppc 代码
文件路径：/src/include/port/atomics/arch-ppc.h
/*-------------------------------------------------------------------------
*
* arch-ppc.h
* Atomic operations considerations specific to PowerPC
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* NOTES:
*
* src/include/port/atomics/arch-ppc.h
*
*-------------------------------------------------------------------------
*/
#if defined(__GNUC__)
/*
* lwsync orders loads with respect to each other, and similarly with stores.
* But a load can be performed before a subsequent store, so sync must be used
* for a full memory barrier.
*/
#define pg_memory_barrier_impl() __asm__ __volatile__ ("sync" : : : "memory")
#define pg_read_barrier_impl() __asm__ __volatile__ ("lwsync" : : : "memory")
#define pg_write_barrier_impl() __asm__ __volatile__ ("lwsync" : : : "memory")
#endif
/* per architecture manual doubleword accesses have single copy atomicity */
#define PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY