Detecting Multiple Arrow KeyPresses

[ACagliano]

So, in Legend of Zelda, I'm using Direct Input to check for keypresses. I have all of the keys I need checked for (code below), but I need to now check for dual arrow keypresses (UP+LEFT, UP+RIGHT, DOWN+LEFT, DOWN+RIGHT)

[KermMartian]

Did you write that code yourself, or take it from someone else? If you wrote it yourself, then you should already know how to detect multiple arrow keys pressed at the same time. The byte returned from Port $01 for direct input has 1 bits for keys that are not pressed and 0 bits for keys that are pressed (counterintuitively). Therefore, if the bit for the [up] arrow key is 0, then that key is pressed, regardless of whatever other keys are pressed and bits are reset. If you want to do diagonal motion, the usual method is to call the movedown/moveleft/moveright/moveup functions, and have each one push and pop af. Therefore, if up and left are pressed, both moveup and moveleft will be called. If you want to call a separate routine moveupleft when up and left are pressed, then you need to cp a to a byte with 1s for everything other than the up and left keys, and 0s for the up and left keys.
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[ACagliano]

Right, I assumed as much, I just wanted to be safe and confirm before I coded incorrectly. And I think I'll use the latter method, having a moveupleft sort of routine.
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-ACagliano

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