package sim_8086

Register :: struct {
    fullname: string,
    bytename: string,
    value: struct #raw_union {
        using _: struct {
            low, high: byte,
        },
        full: u16,
    },
    code: u8,
}

WordSize :: enum {
    None,
    LastBit,
    FourthBit,
    Always8,
    Always16,
}

None :: struct {}

Disp8 :: i8
Disp16 :: i16
Displacement :: union {
    None,
    Disp8,
    Disp16
}

RegisterId :: distinct u8
Immediate8 :: distinct i8
Immediate16 :: distinct i16
ImmediateU8 :: distinct u8
MemoryAddr :: struct {
    addr_id: u8,
    displacement: Displacement,
}
DirectAddress :: distinct i16
SegmentRegister :: distinct i8
Jump :: distinct i8
VariablePort :: struct {}
ShiftRotate :: distinct bool
Repeat :: string
Intersegment :: struct {
    ip: i16,
    cs: i16,
}
DirectWithinSegment :: distinct u16

Operand :: union {
    None,
    RegisterId,
    Immediate8,
    ImmediateU8,
    Immediate16,
    MemoryAddr,
    DirectAddress,
    SegmentRegister,
    Jump,
    VariablePort,
    ShiftRotate,
    Repeat,
    DirectWithinSegment,
    Intersegment,
}

OperandInfo :: enum {
    None,
    Register,
    SegmentRegister,
    RegisterMemory,
    Immediate,
    ImmediateUnsigned,
    Accumulator,
    DirectAddress,
    Jump,
    VariablePort,
    ShiftRotate,
    Repeat,
    DirectWithinSegment,
    Intersegment,
}

RegisterEncodingBits :: enum {
    None,
    FirstByteLast3,
    SecondByteMiddle3,
    SecondByteLast3,
    FirstByteMiddle3,
}

InstructionInfo :: struct {
    mask: u8,
    encoding: u8,
    opname: Op,
    desc: string,
    src: OperandInfo,
    dst: OperandInfo,
    word_size: WordSize,
    reg_info: RegisterEncodingBits,
    has_flip: bool,
    has_sign_extension: bool,
    check_second_encoding: bool,
    consume_extra_bytes: int,
    shift_rotate_flag: bool,
}

Instruction :: struct {
    opname: Op,
    src: Operand,
    dst: Operand,
    info: InstructionInfo,
    is_word: bool,
    indirect_intersegment: bool,
    has_segment: Maybe(Register),
    has_lock: bool,
    bytes_read: int,
    raw_data: []u8,
    debug_msg: string,
}