| Routines

71FA: Get the keypress offset of the last key pressed

Used by the routines at 725E, 7316, F413 and FB3C. Returns with the zero flag set if no game keys were pressed. Otherwise returns with A holding the value from the keypress offset table corresponding to the last key pressed. This offset (an even number from 0x50 to 0x78) points at an entry in the keypress address table at E550. Each entry in that table is the address of the routine for handling a keypress.
71FA | CALL $71BE | Collect the ASCII code of the last key pressed in A
71FD | RET Z | Return if no key was pressed
71FE | SUB $30 | We're only interested in keys with codes 0x30 onwards
7200 | JR C,$71F8 | Jump if none of these was pressed
7202 | LD L,A | Point HL at the relevant entry in the keypress offset table at E500
7203 | LD H,$E5
7205 | LD A,(HL) | Pick up the offset from that table
7206 | AND A | Set the zero flag if the offset is 0x00 (i.e. not a game key)
7207 | RET |