package decoder_8086

OpName :: enum {
    TBD1,
    TBD2,
    TBD3,
    TBD4,
    TBD5,
    TBD6,
    MOV,
    PUSH,
    POP,
    XCHG,
    IN,
    OUT,
    XLAT,
    LEA,
    LDS,
    LES,
    LAHF,
    SAHF,
    PUSHF,
    POPF,
    ADD,
    ADC,
    INC,
    AAA,
    DAA,
    SUB,
    SBB,
    DEC,
    NEG,
    CMP,
    AAS,
    DAS,
    AAM,
    DIV,
    IDIV,
    AAD,
    CBW,
    CWD,
    NOT,
    TEST,
    REP,
    RET,
    RETF,
    INT,
    INT3,
    INTO,
    IRET,
    CLC,
    CMC,
    STC,
    CLD,
    STD,
    CLI,
    STI,
    HLT,
    WAIT,
    ESC,
    LOCK,
    SEGMENT,
    CALL,
    JMP,
    JNZ,
    JNGE,
    JE,
    JZ,
    JL,
    JLE,
    JNG,
    JB,
    JNAE,
    JP,
    JPE,
    JNA,
    JBE,
    JO,
    JS,
    JNE,
    JNL,
    JGE,
    JNLE,
    JG,
    JNB,
    JAE,
    JNBE,
    JA,
    JNP,
    JPO,
    JNO,
    JNS,
    LOOP,
    LOOPZ,
    LOOPNZ,
    JCXZ,
}

// TODO: We should figure out another way of handling this case. The way we're doing it
// isn't that great; we return a string with the instruction name, but ideally we have all
// the instructions accounted for, because eventually we will need the final parsed
// instruction to contain all the information related to it
test_inst := InstructionInfo {
    opname = .NOT, desc = "", mask = 0b11111110, encoding = 0b11110110,
    dst = .RegisterMemory, src = .Immediate, word_size = .LastBit
}

instructions := [?]InstructionInfo {
    { opname = .TBD1, desc = "Immediate to accumulator",
      mask = 0b11000110, encoding = 0b00000100, check_second_encoding = true,
      dst = .Accumulator, src = .Immediate,
      word_size = .LastBit, },
    { opname = .TBD2, desc = "", check_second_encoding = true,
      mask = 0b11111110, encoding = 0b11111110,
      src = .RegisterMemory,
      word_size = .LastBit, },
    { opname = .TBD3, desc = "", check_second_encoding = true,
      mask = 0b11000100, encoding = 0b00000000,
      dst = .RegisterMemory, src = .Register,
      word_size = .LastBit, reg_info = .SecondByteMiddle3, has_flip = true },
    { opname = .TBD4, desc = "", check_second_encoding = true,
      mask = 0b11111100, encoding = 0b10000000,
      dst = .RegisterMemory, src = .Immediate,
      word_size = .LastBit, has_sign_extension = true },
    { opname = .TBD5, desc = "", check_second_encoding = true,
      mask = 0b11111110, encoding = 0b11110110,
      // dst = .Immediate, src = .RegisterMemory, word_size = .LastBit, },
      src = .RegisterMemory, word_size = .LastBit, },
    { opname = .TBD6, desc = "", check_second_encoding = true,
      mask = 0b11111100, encoding = 0b11010000,
      dst = .RegisterMemory, src = .ShiftRotate, word_size = .LastBit, },
    { opname = .MOV, desc = "Register/memory to/from register",
      mask = 0b11111100, encoding = 0b10001000,
      dst = .RegisterMemory, src = .Register,
      word_size = .LastBit, reg_info = .SecondByteMiddle3, has_flip = true },
    { opname = .MOV, desc = "Immediate to register/memory",
      mask = 0b11111110, encoding = 0b11000110,
      dst = .RegisterMemory, src = .Immediate,
      word_size = .LastBit, },
    { opname = .MOV, desc = "Immediate to register",
      mask = 0b11110000, encoding = 0b10110000,
      dst = .Register, src = .Immediate,
      word_size = .FourthBit, reg_info = .FirstByteLast3 },
    { opname = .MOV, desc = "Memory to accumulator",
      mask = 0b11111110, encoding = 0b10100000,
      dst = .Accumulator, src = .DirectAddress,
      word_size = .LastBit, },
    { opname = .MOV, desc = "Accumulator to memory",
      mask = 0b11111110, encoding = 0b10100010,
      dst = .DirectAddress, src = .Accumulator,
      word_size = .LastBit, },
    { opname = .MOV, desc = "Accumulator to memory",
      mask = 0b11111111, encoding = 0b10001100,
      dst = .RegisterMemory, src = .SegmentRegister,
      reg_info = .SecondByteMiddle3 },
    { opname = .PUSH, desc = "", mask = 0b11111000, encoding = 0b01010000,
      src = .Register, reg_info = .FirstByteLast3,
      word_size = .Always16, },
    { opname = .PUSH, desc = "", mask = 0b11100111, encoding = 0b00000110,
      src = .SegmentRegister, reg_info = .FirstByteMiddle3,
      word_size = .Always16, },
    { opname = .POP, desc = "", mask = 0b11111111, encoding = 0b10001111,
      src = .RegisterMemory, word_size = .Always16 },
    { opname = .POP, desc = "", mask = 0b11111000, encoding = 0b01011000,
      src = .Register, reg_info = .FirstByteLast3,
      word_size = .Always16, },
    { opname = .POP, desc = "", mask = 0b11100111, encoding = 0b00000111,
      src = .SegmentRegister, reg_info = .FirstByteMiddle3,
      word_size = .Always16, },
    { opname = .XCHG, desc = "", mask = 0b11111110, encoding = 0b10000110,
      dst = .RegisterMemory, src = .Register,
      reg_info = .SecondByteMiddle3, word_size = .LastBit, has_flip = true },
    { opname = .XCHG, desc = "", mask = 0b11111000, encoding = 0b10010000,
      dst = .Accumulator, src = .Register,
      reg_info = .FirstByteLast3, has_flip = true, word_size = .Always16 },
    { opname = .IN, desc = "", mask = 0b11111110, encoding = 0b11100100,
      dst = .Accumulator, src = .ImmediateUnsigned },
    { opname = .IN, desc = "", mask = 0b11111110, encoding = 0b11101100,
      dst = .Accumulator, src = .VariablePort,
      word_size = .LastBit, },
    { opname = .OUT, desc = "", mask = 0b11111110, encoding = 0b11100110,
      dst = .ImmediateUnsigned, src = .Accumulator,
      word_size = .LastBit, },
    { opname = .OUT, desc = "", mask = 0b11111110, encoding = 0b11101110,
      dst = .VariablePort, src = .Accumulator,
      word_size = .LastBit, },
    { opname = .TEST, desc = "", mask = 0b11111110, encoding = 0b10101000,
      dst = .Accumulator, src = .Immediate, word_size = .LastBit },
    { opname = .XLAT, desc = "", mask = 0b11111111, encoding = 0b11010111,},
    { opname = .LEA, desc = "", mask = 0b11111111, encoding = 0b10001101,
      dst = .Register, src = .RegisterMemory,
      reg_info = .SecondByteMiddle3, word_size = .Always16 },
    { opname = .LDS, desc = "", mask = 0b11111111, encoding = 0b11000101, 
      dst = .Register, src = .RegisterMemory,
      reg_info = .SecondByteMiddle3, word_size = .Always16 },
    { opname = .LES, desc = "", mask = 0b11111111, encoding = 0b11000100,
      dst = .Register, src = .RegisterMemory,
      reg_info = .SecondByteMiddle3, word_size = .Always16 },
    { opname = .LAHF,  desc = "", mask = 0b11111111, encoding = 0b10011111,},
    { opname = .SAHF,  desc = "", mask = 0b11111111, encoding = 0b10011110,},
    { opname = .PUSHF, desc = "", mask = 0b11111111, encoding = 0b10011100,},
    { opname = .POPF,  desc = "", mask = 0b11111111, encoding = 0b10011101,},
    { opname = .INC, desc = "", mask = 0b11111000, encoding = 0b01000000,
      src = .Register, reg_info = .FirstByteLast3, word_size = .Always16 },
    { opname = .AAA,  desc = "", mask = 0b11111111, encoding = 0b00110111,},
    { opname = .DAA,  desc = "", mask = 0b11111111, encoding = 0b00100111,},
    { opname = .DEC, desc = "", mask = 0b11111000, encoding = 0b01001000, 
      src = .Register, reg_info = .FirstByteLast3, word_size = .Always16 },
    { opname = .AAS,  desc = "", mask = 0b11111111, encoding = 0b00111111,},
    { opname = .DAS,  desc = "", mask = 0b11111111, encoding = 0b00101111,},
    { opname = .AAM,  desc = "", mask = 0b11111111, encoding = 0b11010100,},
    { opname = .AAD,  desc = "", mask = 0b11111111, encoding = 0b11010101, consume_extra_bytes = 1 },
    { opname = .CBW,  desc = "", mask = 0b11111111, encoding = 0b10011000,},
    { opname = .CWD,  desc = "", mask = 0b11111111, encoding = 0b10011001,},
    { opname = .TEST, desc = "", mask = 0b11111100, encoding = 0b10000100,
      dst = .RegisterMemory, src = .Register,
      word_size = .LastBit, reg_info = .SecondByteMiddle3, has_flip = true },
    { opname = .REP, desc = "", mask = 0b11111110, encoding = 0b11110010, src = .Repeat },
    { opname = .RET, desc = "", mask = 0b11111111, encoding = 0b11000011,},
    { opname = .RET, src = .Immediate, word_size = .Always16,
      desc = "", mask = 0b11111111, encoding = 0b11000010,},
    { opname = .RETF, desc = "", mask = 0b11111111, encoding = 0b11001011,},
    { opname = .RETF, desc = "", mask = 0b11111111, encoding = 0b11001010,
      src = .Immediate, word_size = .Always16 },
    { opname = .INT, src = .Immediate, desc = "", mask = 0b11111111, encoding = 0b11001101,},
    { opname = .INT3, desc = "", mask = 0b11111111, encoding = 0b11001100,},
    { opname = .INTO, desc = "", mask = 0b11111111, encoding = 0b11001110,},
    { opname = .IRET, desc = "", mask = 0b11111111, encoding = 0b11001111,},
    { opname = .CLC,  desc = "", mask = 0b11111111, encoding = 0b11111000,},
    { opname = .CMC,  desc = "", mask = 0b11111111, encoding = 0b11110101,},
    { opname = .STC,  desc = "", mask = 0b11111111, encoding = 0b11111001,},
    { opname = .CLD,  desc = "", mask = 0b11111111, encoding = 0b11111100,},
    { opname = .STD,  desc = "", mask = 0b11111111, encoding = 0b11111101,},
    { opname = .CLI,  desc = "", mask = 0b11111111, encoding = 0b11111010,},
    { opname = .STI,  desc = "", mask = 0b11111111, encoding = 0b11111011,},
    { opname = .HLT,  desc = "", mask = 0b11111111, encoding = 0b11110100,},
    { opname = .WAIT, desc = "", mask = 0b11111111, encoding = 0b10011011,},
    { opname = .LOCK, desc = "", mask = 0b11111111, encoding = 0b11110000,},
    { opname = .SEGMENT, desc = "", mask = 0b11100111, encoding = 0b00100110,},
    { opname = .CALL, desc = "", mask = 0b11111111, encoding = 0b10011010, src = .Intersegment  },
    { opname = .JMP, desc = "", mask = 0b11111111, encoding = 0b11101010, src = .Intersegment  },
    { opname = .JMP, desc = "", mask = 0b11111111, encoding = 0b11101001, src = .DirectWithinSegment },
    { opname = .CALL, desc = "", mask = 0b11111111, encoding = 0b11101000, src = .DirectWithinSegment },
    { opname = .JE,     mask = 0b11111111, encoding = 0b01110100, src = .Jump, desc = "Jump on not zero", },
    { opname = .JZ,     mask = 0b11111111, encoding = 0b01110100, src = .Jump, desc = "Jump on not zero", },

    { opname = .JL,     mask = 0b11111111, encoding = 0b01111100, src = .Jump, desc = "Jump on not zero", },
    { opname = .JNGE,   mask = 0b11111111, encoding = 0b01111100, src = .Jump, desc = "Jump on not zero", },

    { opname = .JLE,    mask = 0b11111111, encoding = 0b01111110, src = .Jump, desc = "Jump on not zero", },
    { opname = .JNG,    mask = 0b11111111, encoding = 0b01111110, src = .Jump, desc = "Jump on not zero", },

    { opname = .JB,     mask = 0b11111111, encoding = 0b01110010, src = .Jump, desc = "Jump on not zero", },
    { opname = .JNAE,   mask = 0b11111111, encoding = 0b01110010, src = .Jump, desc = "Jump on not zero", },

    { opname = .JBE,    mask = 0b11111111, encoding = 0b01110110, src = .Jump, desc = "Jump on not zero", },
    { opname = .JNA,    mask = 0b11111111, encoding = 0b01110110, src = .Jump, desc = "Jump on not zero", },

    { opname = .JP,     mask = 0b11111111, encoding = 0b01111010, src = .Jump, desc = "Jump on not zero", },
    { opname = .JPE,    mask = 0b11111111, encoding = 0b01111010, src = .Jump, desc = "Jump on not zero", },

    { opname = .JO,     mask = 0b11111111, encoding = 0b01110000, src = .Jump, desc = "Jump on not zero", },
    { opname = .JS,     mask = 0b11111111, encoding = 0b01111000, src = .Jump, desc = "Jump on not zero", },

    { opname = .JNE,    mask = 0b11111111, encoding = 0b01110101, src = .Jump, desc = "Jump on not zero", },
    { opname = .JNZ,    mask = 0b11111111, encoding = 0b01110101, src = .Jump, desc = "Jump on not zero", },

    { opname = .JNL,    mask = 0b11111111, encoding = 0b01111101, src = .Jump, desc = "Jump on not zero", },
    { opname = .JGE,    mask = 0b11111111, encoding = 0b01111101, src = .Jump, desc = "Jump on not zero", },

    { opname = .JNLE,   mask = 0b11111111, encoding = 0b01111111, src = .Jump, desc = "Jump on not zero", },
    { opname = .JG,     mask = 0b11111111, encoding = 0b01111111, src = .Jump, desc = "Jump on not zero", },

    { opname = .JNB,    mask = 0b11111111, encoding = 0b01110011, src = .Jump, desc = "Jump on not zero", },
    { opname = .JAE,    mask = 0b11111111, encoding = 0b01110011, src = .Jump, desc = "Jump on not zero", },

    { opname = .JNBE,   mask = 0b11111111, encoding = 0b01110111, src = .Jump, desc = "Jump on not zero", },
    { opname = .JA,     mask = 0b11111111, encoding = 0b01110111, src = .Jump, desc = "Jump on not zero", },

    { opname = .JNP,    mask = 0b11111111, encoding = 0b01111011, src = .Jump, desc = "Jump on not zero", },
    { opname = .JPO,    mask = 0b11111111, encoding = 0b01111011, src = .Jump, desc = "Jump on not zero", },

    { opname = .JNO,    mask = 0b11111111, encoding = 0b01110001, src = .Jump, desc = "Jump on not zero", },

    { opname = .JNS,    mask = 0b11111111, encoding = 0b01111001, src = .Jump, desc = "Jump on not zero", },
    { opname = .LOOP,   mask = 0b11111111, encoding = 0b11100010, src = .Jump, desc = "Jump on not zero", },
    { opname = .LOOPZ,  mask = 0b11111111, encoding = 0b11100001, src = .Jump, desc = "Jump on not zero", },
    { opname = .LOOPNZ, mask = 0b11111111, encoding = 0b11100000, src = .Jump, desc = "Jump on not zero", },
    { opname = .JCXZ,   mask = 0b11111111, encoding = 0b11100011, src = .Jump, desc = "Jump on not zero", },
}