rori

Rotate right (Immediate)

This instruction is defined by:

anyOf:
- B, version >= B@1.0.0
- Zbb, version >= Zbb@1.0.0
- Zbkb, version >= Zbkb@1.0.0
- Zk, version >= Zk@1.0.0
- Zkn, version >= Zkn@1.0.0
- Zks, version >= Zks@1.0.0

This instruction is included in the following profiles:

RVA22U64 (Mandatory)
RVA23U64 (Mandatory)
RVB23U64 (Mandatory)

Encoding

This instruction has different encodings in RV32 and RV64.

RV32
RV64

Assembly format

rori rd, rs1, shamt

Synopsis

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

This instruction performs a rotate right of rs1 by the amount in the least-significant log2(XLEN) bits of shamt. For RV32, the encodings corresponding to shamt[5]=1 are reserved.

Access

M	HS	U	VS	VU
Always	Always	Always	Always	Always

Always

Decode Variables

RV32
RV64

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

idl

Bits<6> shamt = $encoding[25:20];
Bits<5> rs1 = $encoding[19:15];
Bits<5> rd = $encoding[11:7];

idl

Execution

IDL
Sail

if (implemented?(ExtensionName::B) && (CSR[misa].B == 1'b0)) {
  raise(ExceptionCode::IllegalInstruction, mode(), $encoding);
}
XReg shamt = (xlen() == 32) ? shamt[4:0] : shamt[5:0];
X[rd] = (X[rs1] >> shamt) | (X[rs1] << (xlen() - shamt));

idl

{
  let rs1_val = X(rs1);
  let result : xlenbits = if sizeof(xlen) == 32
                          then rs1_val >>> shamt[4..0]
                          else rs1_val >>> shamt;
  X(rd) = result;
  RETIRE_SUCCESS
}

sail

Exceptions

This instruction may result in the following synchronous exceptions:

IllegalInstruction