localparam [0:0]
  OFFSET_SOURCE_IMM = 1'd0,
  OFFSET_SOURCE_RS1 = 1'd1;

localparam [0:0]
  OP_B_SOURCE_IMM = 1'd0,
  OP_B_SOURCE_RS2 = 1'd1;

localparam[2:0]
  ALU_RESULT_ADD = 3'd0,
  ALU_RESULT_SR  = 3'd1,
  ALU_RESULT_LT  = 3'd2,
  ALU_RESULT_XOR = 3'd3,
  ALU_RESULT_OR  = 3'd4,
  ALU_RESULT_AND = 3'd5;

localparam [0:0]
  ALU_CMP_LT = 1'b0,
  ALU_CMP_EQ = 1'b1;

/*
 source
 ADD, SUB
 SL,SR
 SLT
 XOR,
 OR
 AND
*/

   /*
    300 mstatus RWSC
    304 mie SCWi
    305 mtvec RW
    344 mip CWi

    340 mscratch
    341 mepc  RW
    342 mcause R
    343 mtval
    */
localparam [2:0]
  CSR_SEL_MSTATUS  = 3'd0,
  CSR_SEL_MIE      = 3'd1,
  CSR_SEL_MTVEC    = 3'd2,
  CSR_SEL_MIP      = 3'd3,
  CSR_SEL_MSCRATCH = 3'd4,
  CSR_SEL_MEPC     = 3'd5,
  CSR_SEL_MCAUSE   = 3'd6,
  CSR_SEL_MTVAL    = 3'd7;

localparam [1:0]
  CSR_SOURCE_CSR = 2'b00,
  CSR_SOURCE_EXT = 2'b01,
  CSR_SOURCE_SET = 2'b10,
  CSR_SOURCE_CLR = 2'b11;