exec_C_ADDI :: GPR_Addr -> InstrField -> Machine_State -> Machine_State
exec_C_ADDI    rd_rs1      nzimm6        mstate =
  let
    imm12   = sign_extend  6  12  nzimm6
    instr_I = ADDI  rd_rs1  rd_rs1  imm12
    is_C    = True
    mstate1 = exec_ADDI  is_C  instr_I  mstate
  in
    mstate1

-- ================================================================
-- C_JAL: expands to JAL

exec_C_JAL :: InstrField -> Machine_State -> Machine_State