| Routines

37687: Check whether ENTER or the fire button is being pressed

Used by the routine at 37596. Returns with the zero flag reset if ENTER or the fire button on the joystick is being pressed.
37687 | LD A,(33881) | Pick up the Kempston joystick indicator from 33881
37690 | OR A | Is the joystick connected?
37691 | JR Z,37698 | Jump if not
37693 | IN A,(31) | Collect input from the joystick
37695 | BIT 4,A | Is the fire button being pressed?
37697 | RET NZ | Return (with the zero flag reset) if so
37698 | LD BC,49150 | Read keys H-J-K-L-ENTER
37701 | IN A,(C)
37703 | AND 1 | Keep only bit 0 of the result (ENTER)
37705 | CP 1 | Reset the zero flag if ENTER is being pressed
37707 | RET |