Function pir_8_emu::binutils::pir_8_emu::display::register::sp_write

pub fn sp_write(
    x_start: usize, 
    y_start: usize, 
    pc: &mut SpecialPurposeRegister<u16>, 
    sp: &mut SpecialPurposeRegister<u16>, 
    adr: &mut SpecialPurposeRegister<u16>, 
    ins: &mut SpecialPurposeRegister<u8>
)

Prepare the "Special-purpose registers" window at the specified coords

The window is 27x3, laid out as follows:

 Special-purpose registers
PC  0x0000       SP  0x0000
ADR 0x0000       INS 0x00