FNOP
No Operation
stableVMJITAOTinstruction
Encodings
| Opcode | Instruction | Op/En | 64-bit | Compat/Legacy | Description |
|---|---|---|---|---|---|
D9 D0 | FNOP | Valid | Valid | No operation is performed. |
Measured cost
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Description
Performs no FPU operation. This instruction takes up space in the instruction stream but does not affect the FPU or machine context, except the EIP register and the FPU Instruction Pointer.
This instruction's operation is the same in non-64-bit modes and 64-bit mode.
FPU Flags Affected C0, C1, C2, C3 undefined.
Floating-Point Exceptions
None.
Exceptions
Protected mode
#NM | CR0.EM[bit 2] or CR0.TS[bit 3] = 1. |
#MF | If there is a pending x87 FPU exception. |
#UD | If the LOCK prefix is used. |
Real address mode
| Same exceptions as in protected mode. |
Virtual-8086 mode
| Same exceptions as in protected mode. |
Compatibility mode
| Same exceptions as in protected mode. |
64-bit mode
| Same exceptions as in protected mode. |