structures:
  main:
    bits: 32
    ranges:
      31-20:
        name: op2
        depends-on: 5
        values:
          0:
            description: second operand is an immediate value
            structure: immediateOp
          1:
            description: second operand is a register
            structure: registerOp
      19-15:
        name: rs1
      14-12:
        name: funct3
        description: operation
        values:
          000: add / sub
          100: xor
          110: or
          111: and
          001: sl
          101: sr
      11-7:
        name: rd
      6:
        name: 0
      5:
        name: I
      4:
        name: 1
      3:
        name: 0
      2:
        name: 0
      1:
        name: 1
      0:
        name: 1
  immediateOp:
    bits: 12
    ranges:
      11-0:
        name: 12-bit immediate value
        description: signed number
  registerOp:
    bits: 12
    ranges:
      11-5:
        name: funct7
        description: function modifier
        values:
          0000000: default (add, srl)
          "0100000": sub, sra
      4-0:
        name: rs2
        description: second register operand