c.nop

Non-operation

C.NOP does not change any user-visible state, except for advancing the pc and accepting any HINTs. C.NOP expands into addi x0, x0, 0. C.NOP with non-zero immediate values are HINTs.

This instruction must have data-independent timing when extension Zkt is enabled.

Assembly format

c.nop imm

Decode Variables

signed Bits<6> imm = sext({$encoding[12], $encoding[6:2]}, 6);

Execution

if (implemented?(ExtensionName::C) && MISA_CSR_IMPLEMENTED && (CSR[misa].C == 1'b0)) {
  reserved_instruction($encoding);
}

Exceptions

This instruction may result in the following synchronous exceptions:

  • IllegalInstruction

Encoding

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Defining extension

Zca

Access

M

Always

Containing profiles

  • Mandatory: None

  • Optional: RVA20S64, RVA20U64, RVA22S64, RVA22U64, RVA23S64, RVA23U64, RVB23S64, RVB23U64, RVI20U32, RVI20U64