roriw

Rotate right word (Immediate)

This instruction is defined by:

  • anyOf:

    • B, version >= 0

    • Zbb, version >= 0

    • Zbkb, version >= 0

    • Zk, version >= 0

    • Zkn, version >= 0

    • Zks, version >= 0

This instruction is included in the following profiles:

  • RVA22S64 (Mandatory)

  • RVA22U64 (Mandatory)

Encoding

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Assembly format

roriw rd, rs1, shamt

Synopsis

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

This instruction performs a rotate right on the least-significant word of rs1 by the amount in the least-significant log2(XLEN) bits of shamt. The resulting word value is sign-extended by copying bit 31 to all of the more-significant bits.

Access

M HS U VS VU

Always

Always

Always

Always

Always

Decode Variables

Bits<5> shamt = $encoding[24:20];
Bits<5> rs1 = $encoding[19:15];
Bits<5> rd = $encoding[11:7];

Execution

  • IDL

  • Sail

if (implemented?(ExtensionName::B) && (CSR[misa].B == 1'b0)) {
  raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg rs1_word = X[rs1][31:0];
XReg unextended_result = (X[rs1] >> shamt) | (X[rs1] << (32 - shamt));
X[rd] = {{32{unextended_result[31]}}, unextended_result};
{
  let rs1_val = (X(rs1))[31..0];
  let result : xlenbits = sign_extend(rs1_val >>> shamt);
  X(rd) = result;
  RETIRE_SUCCESS
}

Exceptions

This instruction may result in the following synchronous exceptions:

  • IllegalInstruction