Advanced Micro Devices, Inc.
System and method for a lightweight fencing operation

Abstract:

A system and method for a lightweight fence is described. In particular, micro-operations including a fencing micro-operation are dispatched to a load queue. The fencing micro-operation allows micro-operations younger than the fencing micro-operation to execute, where the micro-operations are related to a type of fencing micro-operation. The fencing micro-operation is executed if the fencing micro-operation is the oldest memory access micro-operation, where the oldest memory access micro-operation is related to the type of fencing micro-operation. The fencing micro-operation determines whether micro-operations younger than the fencing micro-operation have load ordering violations and if load ordering violations are detected, the fencing micro-operation signals the retire queue that instructions younger than the fencing micro-operation should be flushed. The instructions to be flushed should include all micro-operations with load ordering violations.