/*!
   \file Instruction.h
   \brief Decode instructions part of the RISC-V
   \author Màrius Montón
   \date August 2018
*/

#ifndef C_INSTRUCTION__H
#define C_INSTRUCTION__H

#include "systemc"

using namespace sc_core;
using namespace sc_dt;
using namespace std;

typedef enum {
OP_C_ADDI4SPN,
OP_C_FLD,
OP_C_LW,
OP_C_FLW,
OP_C_FSD,
OP_C_SW,
OP_C_FSW,

OP_C_NOP,
OP_C_ADDI,
OP_C_JAL,
OP_C_LI,
OP_C_ADDI16SP,
OP_C_LUI,
OP_C_SRLI,
OP_C_SRAI,
OP_C_ANDI,
OP_C_SUB,
OP_C_XOR,
OP_C_OR,
OP_C_AND,
OP_C_J,
OP_C_BEQZ,
OP_C_BNEZ,

OP_C_SLLI,
OP_C_FLDSP,
OP_C_LWSP,
OP_C_FLWSP,
OP_C_JR,
OP_C_MV,
OP_C_EBREAK,
OP_C_JALR,
OP_C_ADD,
OP_C_FSDSP,
OP_C_SWSP,
OP_C_FSWSP,

OP_C_ERROR
} op_C_Codes;


typedef enum {
  C_ADDI4SPN = 0b000,
  C_FLD      = 0b001,
  C_LW       = 0b010,
  C_FLW      = 0b011,
  C_FSD      = 0b101,
  C_SW       = 0b110,
  C_FSW      = 0b111,

  C_ADDI     = 0b000,
  C_JAL      = 0b001,
  C_LI       = 0b010,
  C_ADDI16SP = 0b011,
  C_SRLI     = 0b100,
  C_2_SRLI   = 0b00,
  C_2_SRAI   = 0b01,
  C_2_ANDI   = 0b10,
  C_2_SUB    = 0b11,
  C_3_SUB    = 0b00,
  C_3_XOR    = 0b01,
  C_3_OR     = 0b10,
  C_3_AND    = 0b11,
  C_J        = 0b101,
  C_BEQZ     = 0b110,
  C_BNEZ     = 0b111,

  C_SLLI     = 0b000,
  C_FLDSP    = 0b001,
  C_LWSP     = 0b010,
  C_FLWSP    = 0b011,
  C_JR       = 0b100,
  C_FDSP     = 0b101,
  C_SWSP     = 0b110,
  C_FWWSP    = 0b111,
} C_Codes;

/**
 * @brief Instruction decoding and fields access
 */
class C_Instruction{
public:

  /**
   * @brief Constructor
   * @param instr Instruction to decode
   */
  C_Instruction(sc_uint<32> instr);

  /**
   * @brief Access to opcode field
   * @return return opcode field
   */
  inline int32_t opcode() {
    return m_instr.range(1,0);
  }

  /**
   * @brief Access to rd field
   * @return rd field
   */
  inline int32_t get_rd() {
    return m_instr.range(11, 7);
  }

  inline void set_rd(int32_t value) {
    m_instr.range(11,7) = value;
  }

  inline int32_t get_rdp() {
    return m_instr.range(4, 2) + 8;
  }

  /**
   * @brief Access to rs1 field
   * @return rs1 field
   */
  inline int32_t get_rs1() {
    return m_instr.range(11, 7);
  }

  inline void set_rs1(int32_t value) {
    m_instr.range(11,7) = value;
  }


  inline int32_t get_rs1p() {
    return m_instr.range(9, 7) + 8;
  }

  /**
   * @brief Access to rs2 field
   * @return rs2 field
   */
  inline int32_t get_rs2() {
    return m_instr.range(6, 2);
  }

  inline void set_rs2(int32_t value) {
    m_instr.range(6,2) = value;
  }

  inline int32_t get_rs2p() {
    return m_instr.range(4, 2) + 8;
  }

  inline int32_t get_funct3() {
    return m_instr.range(15, 13);
  }

  inline void set_funct3(int32_t value) {
    m_instr.range(15,13) = value;
  }

  /**
   * @brief Access to immediate field for I-type
   * @return immediate_I field
   */
  inline int32_t get_imm_I() {
    int32_t aux = 0;

    aux = m_instr.range(31, 20);

    /* sign extension (optimize) */
    if (m_instr[31] == 1) {
      aux |= (0b11111111111111111111) << 12;
    }

    return aux;
  }

  inline void set_imm_I(int32_t value) {
    m_instr.range(31,20) = value;
  }

  /**
   * @brief Access to immediate field for S-type
   * @return immediate_S field
   */
  inline int32_t get_imm_S() {
    int32_t aux = 0;

    aux  = m_instr.range(31, 25) << 5;
    aux |= m_instr.range(11,7);

    if (m_instr[31] == 1) {
      aux |= (0b11111111111111111111) << 12;
    }

    return aux;
  }

  inline void set_imm_S(int32_t value) {
    sc_uint<32> aux = value;

    m_instr.range(31,25) = aux.range(11,5);
    m_instr.range(11,7) = aux.range(4,0);
  }

  /**
   * @brief Access to immediate field for U-type
   * @return immediate_U field
   */
  inline int32_t get_imm_U() {
    return m_instr.range(31, 12);
  }

  inline void set_imm_U(int32_t value) {
    m_instr.range(31,12) = (value << 12);
  }

  /**
   * @brief Access to immediate field for B-type
   * @return immediate_B field
   */
  inline int32_t get_imm_B() {
    int32_t aux = 0;

    aux |= m_instr[7] << 11;
    aux |= m_instr.range(30, 25) << 5;
    aux |= m_instr[31] << 12;
    aux |= m_instr.range(11, 8) << 1;

    if (m_instr[31] == 1) {
      aux |= (0b11111111111111111111) << 12;
    }

    return aux;
  }

  inline void set_imm_B(int32_t value) {
    sc_uint<32> aux = value;

    m_instr[31] = aux[12];
    m_instr.range(30,25) = aux.range(10,5);
    m_instr.range(11,7) = aux.range(4,1);
    m_instr[6] = aux[11];
  }
  /**
   * @brief Access to immediate field for J-type
   * @return immediate_J field
   */
  inline int32_t get_imm_J() {
    int32_t aux = 0;

    aux = m_instr[12] << 11;
    aux |= m_instr[11] << 4;
    aux |= m_instr[10] << 9;
    aux |= m_instr[9] << 8;
    aux |= m_instr[8] << 10;
    aux |= m_instr[7] << 6;
    aux |= m_instr[6] << 7;
    aux |= m_instr.range(5,3) << 1;
    aux |= m_instr[2] << 5;

    if (m_instr[12] == 1) {
        aux |= 0b1111 << 12;
    }

    return aux;
  }

  inline void set_imm_J(int32_t value) {
    sc_uint<32> aux = (value << 20);

    m_instr[31] = aux[20];
    m_instr.range(30,21) = aux.range(10,1);
    m_instr[20] = aux[11];
    m_instr.range(19,12) = aux.range(19,12);
  }

  inline int32_t get_imm_L() {
      int32_t aux = 0;

      aux = m_instr.range(12,10) << 3;
      aux |= m_instr[6] << 2;
      aux |= m_instr[5] << 6;

      return aux;
  }

  inline int32_t get_imm_LWSP() {
    int32_t aux = 0;

    aux = m_instr[12] << 5;
    aux |= m_instr.range(6,4) << 2;
    aux |= m_instr.range(3,2) << 6;

    return aux;
  }

  inline int32_t get_imm_ADDI() {
    int32_t aux = 0;

    aux = m_instr[12] << 5;
    aux |= m_instr.range(6,2);

    if (m_instr[12] == 1) {
      aux |= 0b11111111111111111111111111 << 6;
    }
    return aux;
  }

  inline int32_t get_imm_ADDI4SPN() {
    int32_t aux = 0;

    aux = m_instr.range(12,11) << 4;
    aux |= m_instr.range(10,7) << 6;
    aux |= m_instr[6] << 2;
    aux |= m_instr[5] << 3;

    return aux;
  }

  inline int32_t get_imm_ADDI16SP() {
    int32_t aux = 0;

    aux = m_instr[12] << 9;
    aux |= m_instr[6] << 4;
    aux |= m_instr[5] << 6;
    aux |= m_instr[4] << 8;
    aux |= m_instr[3] << 7;
    aux |= m_instr[2] << 5;

    if (m_instr[12] == 1) {
      aux |= 0b1111111111111111111111 << 10;
    }
    return aux;
  }

  inline int32_t get_imm_CSS() {
    int32_t aux = 0;
    aux = m_instr.range(12,9) << 2;
    aux |= m_instr.range(8,7) << 6;

    return aux;
  }

  inline int32_t get_imm_CB() {
    int32_t aux = 0;

    aux = m_instr[12] << 8;
    aux |= m_instr[11] << 4;
    aux |= m_instr[10] << 3;
    aux |= m_instr[6] << 7;
    aux |= m_instr[5] << 6;
    aux |= m_instr[4] << 2;
    aux |= m_instr[3] << 1;
    aux |= m_instr[2] << 5;

    if (m_instr[12] == 1) {
      aux |= 0b11111111111111111111111 << 9;
    }

    return aux;
  }

  inline int32_t get_imm_LUI() {
    int32_t aux = 0;

    aux = m_instr[12] << 17;
    aux |=  m_instr.range(6,2) << 12;

    if (m_instr[12] == 1) {
      aux |= 0b111111111111111 << 17;
    }

    return aux;
  }

  inline int32_t get_csr() {
    return get_imm_I();
  }

  /**
   * @brief Decodes opcode of instruction
   * @return opcode of instruction
   */
  op_C_Codes decode();

  inline void dump() {
    cout << hex << "0x" << m_instr << dec << endl;
  }
private:
  sc_uint<32> m_instr;
};

#endif