image/svg+xml WBNOINVD—Write Back and Do Not Invalidate Cache Instruction Operand Encoding Description The WBNOINVD instruction writes back all modified cache lines in the processor’s internal cache to main memory but does not invalidate (flush) the internal caches. After executing this instruction, the processor does not wait for the external caches to complete their write-back operation before proceeding with instruction execution. It is the responsibility of hardware to respond to the cache write-back signal. The amount of time or cycles for WBNOINVD to complete will vary due to size and other factors of different cache hierarchies. As a consequence, the use of the WBNOINVD instruction can have an impact on logical processor interrupt/event response time. The WBNOINVD instruction is a privileged instruction. When the processor is running in protected mode, the CPL of a program or procedure must be 0 to execute this instruction. This instruction is also a serializing instruction (see “Serializing Instructions” in Chapter 8 of the Intel® 64 and IA-32 Architectures Software Developer’s Manual, Volume 3A ). This instruction’s operation is the same in non-64-bit modes and 64-bit mode. Operation WriteBack(InternalCaches); Continue; (* Continue execution *) Intel C/C++ Compiler Intrinsic Equivalent WBNOINVD void _wbnoinvd(void); Flags Affected None. Protected Mode Exceptions #GP(0)If the current privilege level is not 0. #UD If the LOCK prefix is used. Real-Address Mode Exceptions #UD If the LOCK prefix is used. Virtual-8086 Mode Exceptions #GP(0)WBNOINVD cannot be executed at the virtual-8086 mode. Compatibility Mode Exceptions Same exceptions as in protected mode. Opcode / Instruction Op/ En 64/32 bit Mode Support CPUID Feature Flag Description F3 0F 09 WBNOINVD ZOV/VWBNOINVDWrite back and do not flush internal caches; initiate writing-back without flushing of external caches. Op/EnTupleOperand 1Operand 2Operand 3Operand 4 ZONANANANANA image/svg+xml 64-Bit Mode Exceptions Same exceptions as in protected mode. This UNOFFICIAL reference was generated from the official Intel® 64 and IA-32 Architectures Software Developer’s Manual by a dumb script. There is no guarantee that some parts aren't mangled or broken and is distributed WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE .