Purpose
Enforce In-order Execution of Input/Output (EIEIO).
The EIEIO directive allows you to specify that all I/O storage access instructions preceding the directive complete before any I/O access instruction subsequent to the directive can begin. Use EIEIO when managing shared data instruction where the execution order of load/store access is significant.
EIEIO can provide the necessary functionality for controlling I/O stores without the cost to performance that can occur with other synchronization instructions.
Syntax
>>-EIEIO------------------------------------------------------->< |