Re: A86: Key checking...
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Re: A86: Key checking...
This would check for the exit key...
ld a,%10111111
out (1),a
nop ;these are really optional
nop
in a,(1)
bit 6,a
jp z,exit_was_pressed
In the first line, whichever bit is left 0 corresponds to a group of
keys to check (bit 7 doesn't do anything). The bit 6,a line checks for
a single key out of that group. The file 86ports.txt on ticalc.org has
a chart of all the keys...
Eric Greening wrote:
>
> I'm fairly new to assembly for z80. I know 68k good though. I was
> wondering how I would make the program check keys like this:
>
> Loop:
> ld a,%01111110
> out (1),a
> nop
> nop
> in a,(1)
> bit 3,a
> jr z,Up
> bit 2,a
> jr z,Right
> bit 1,a
> jr z,Left
> bit 0,a
> jr z,Exit
> jr nz,Loop
>
> I was wondering, how would I check for the exit key using this method?
> I appreciate any help you can give me.
>
> Eric Greening
References: