c.addi

Add a sign-extended non-zero immediate

This instruction is defined by:

Encoding

svg

Synopsis

C.ADDI adds the non-zero sign-extended 6-bit immediate to the value in register rd then writes the result to rd. C.ADDI expands into addi rd, rd, imm. C.ADDI is only valid when rd ≠ x0 and imm ≠ 0. The code points with rd=x0 encode the C.NOP instruction; the remaining code points with imm=0 encode HINTs.

Access

M

HS

U

VS

VU

Always

Always

Always

Always

Always

Decode Variables

Bits<6> imm = {$encoding[12], $encoding[6:2]};
Bits<5> rd = $encoding[11:7];

Execution

  • Pruned, XLEN == 64

  • Original

X[rd] = X[rd] + imm;
if (implemented?(ExtensionName::C) && (CSR[misa].C == 1'b0)) {
  raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
X[rd] = X[rd] + imm;