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Intel Pentium CPU Instruction Set Reference

NOP instruction - No Operation

Code Mnemonic Description
90 NOP No operation


Performs no operation. This instruction is a one-byte instruction that takes up space in the instruction stream but does not affect the machine context, except the EIP register.

The NOP instruction is an alias mnemonic for the XCHG (E)AX, (E)AX instruction.

Operands Bytes Clocks
1 1 UV


ID unaffected DF unaffected
VIP unaffected IF unaffected
VIF unaffected TF unaffected
AC unaffected SF unaffected
VM unaffected ZF unaffected
RF unaffected AF unaffected
NT unaffected PF unaffected
IOPL unaffected CF unaffected
OF unaffected