serialize

Serialize Instruction Execution

SERIALIZE

Forces serialization of instruction fetch/execution.

Details

Serializes instruction execution by ensuring all prior instructions have completed and all memory operations are ordered before subsequent instructions execute. This instruction blocks out-of-order execution, flushes the pipeline, and may have significant performance impact. No flags are modified; the instruction requires SERIALIZE CPU feature and may incur substantial latency.

Pseudocode Operation

IF CPUID.SERIALIZE = 0 THEN #UD FI;
WAIT_FOR_ALL_PRIOR_INSTRUCTIONS();
FLUSH_EXECUTION_PIPELINE();
CLEAR_OUT_OF_ORDER_BUFFERS();

Example

SERIALIZE

Encoding

Binary Layout
0F
+0
01
+1
E8
+2
 
Format Legacy
Opcode NP 0F 01 E8
Extension SERIALIZE

Operands

Reference (Intel® SDM)

Instruction Forms

Opcode Instruction Op/En 64/32-bit Mode CPUID Description
NP 0F 01 E8 SERIALIZE ZO V/V SERIALIZE Serialize instruction fetch and execution.

Description

Serializes instruction execution. Before the next instruction is fetched and executed, the SERIALIZE instruction ensures that all modifications to flags, registers, and memory by previous instructions are completed, draining all buffered writes to memory. This instruction is also a serializing instruction as defined in the section “Serializing Instructions” in Chapter 11 of the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 3A. SERIALIZE does not modify registers, arithmetic flags, or memory.

Operation

Wait_On_Fetch_And_Execution_Of_Next_Instruction_Until(preceding_instructions_complete_and_preceding_stores_globally_visible);

Intel C/C++ Compiler Intrinsic Equivalent

SERIALIZE void _serialize(void);

Exceptions

SIMD Floating-Point Exceptions

None.

Other Exceptions

#UD If the LOCK prefix is used. If CPUID.07H.00H:EDX.SERIALIZE[14] = 0. SERIALIZE—Serialize Instruction Execution Vol. 2B 4-621