slli

Shift left logical immediate

This instruction is defined by:

  • I, version >= I@2.1.0

This instruction is included in the following profiles:

  • MockProfile 64-bit S-mode (Mandatory)

  • MockProfile 64-bit Unpriv (Mandatory)

  • RVA20S64 (Mandatory)

  • RVA20U64 (Mandatory)

  • RVA22S64 (Mandatory)

  • RVA22U64 (Mandatory)

  • RVA23M64 (Mandatory)

  • RVA23S64 (Mandatory)

  • RVA23U64 (Mandatory)

  • RVB23M64 (Mandatory)

  • RVB23S64 (Mandatory)

  • RVB23U64 (Mandatory)

  • RVI20U32 (Mandatory)

  • RVI20U64 (Mandatory)

Encoding

This instruction has different encodings in RV32 and RV64.

  • RV32

  • RV64

svg
svg

Assembly format

slli rd, rs1, shamt

Synopsis

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

Shift the value in xs1 left by shamt, and store the result in xd

Access

M HS U VS VU

Always

Always

Always

Always

Always

Decode Variables

  • RV32

  • RV64

Bits<5> shamt = $encoding[24:20];
Bits<5> xs1 = $encoding[19:15];
Bits<5> xd = $encoding[11:7];
Bits<6> shamt = $encoding[25:20];
Bits<5> xs1 = $encoding[19:15];
Bits<5> xd = $encoding[11:7];

Execution

  • IDL

  • Sail

X[xd] = X[xs1] << shamt;
{
  let xs1_val = X(xs1);
  /* the decoder guaxd should ensure that shamt[5] = 0 for RV32 */
  let result : xlenbits = match op {
    RISCV_SLLI => if   sizeof(xlen) == 32
                  then xs1_val << shamt[4..0]
                  else xs1_val << shamt,
    RISCV_SRLI => if   sizeof(xlen) == 32
                  then xs1_val >> shamt[4..0]
                  else xs1_val >> shamt,
    RISCV_SRAI => if   sizeof(xlen) == 32
                  then shift_right_arith32(xs1_val, shamt[4..0])
                  else shift_right_arith64(xs1_val, shamt)
  };
  X(xd) = result;
  RETIRE_SUCCESS
}