Routines
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33977: Debounce keyboard
Used by the routines at PercentageAscii and SaveGame.
Waits until the current key has been released.
DebounceAnyKey 33977 XOR A Read from the keyboard port.
33978 IN A,(254)
33980 AND %00011111 Keep bits 0-4, one for each key in the half-row. XOR A then IN A,(254) reads every half-row at once, and a pressed key reads as a reset bit.
33982 CP 31 Loop back to DebounceAnyKey if a key is being pressed.
33984 JR NZ,DebounceAnyKey
Normal_AnyKey 33986 XOR A Read from the keyboard port.
33987 IN A,(254)
33989 AND %00011111 Keep bits 0-4, one for each key in the half-row. XOR A then IN A,(254) reads every half-row at once, and a pressed key reads as a reset bit.
33991 CP 31 Loop back to Normal_AnyKey until any key has been pressed.
33993 JR Z,Normal_AnyKey
33995 RET Return.
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