/// Registers.  numbered 1-16 publicly.
/// Privately using zero base array so -1 to shift from pub to priv.
#[derive(Clone, Copy)]
pub struct Chip8Registers {
    registers: [u8; 16],
    i_register: u16,
    pc: u16
}

impl Chip8Registers {
    pub fn advance_pc(&mut self) {
        self.pc += 2;
    }
}

impl Default for Chip8Registers {
    fn default() -> Self {
        Chip8Registers {
            registers: [0x00; 16],
            i_register: 0x00,
            pc: 0x200
        }
    }
}

impl Chip8Registers {
    pub fn poke_pc(&mut self, new_pc: u16) {
        self.pc = new_pc
    }
    pub fn peek_i(&self) -> u16 {
        self.i_register
    }

    pub fn poke_i(&mut self, new_value: u16) {
        self.i_register = new_value;
    }
    pub fn peek(&self, register_number: u8) -> u8 {
        self.registers[(register_number) as usize]
    }

    pub fn poke(&mut self, register_number: u8, value: u8) {
        self.registers[(register_number) as usize] = value;
    }

    pub fn peek_pc(&self) -> u16 {
        self.pc
    }

    pub fn set_pc(&mut self, new_pc: u16) {
        self.pc = new_pc
    }
}


#[cfg(test)]
mod test {

}