pub fn push(&mut self, value: u8) {
        let sp = self.sp as u16;
        self.write(0x100 + sp, value);

        // stack grows downward
        self.sp -= 1;
    }
// push a value to the stack
push a value to the stack
push a value to the stack
pub fn push(&mut self, value: u8) {
        let sp = self.sp as u16;
        self.write(0x100 + sp, value);
        // stack grows downward
        self.sp -= 1;
    }
pub fn push ( & mut self , value : u8 ) { let sp = self . sp as u16 ; self . write ( 0x100 + sp , value ) ; // stack grows downward self . sp -= 1 ; }
push a value to the stack
push a value to the stack
&mut self
value
u8