><< >How is the value determined using indirect-x and indirect-y?
> >How is the address determined using indirect-x and indirect-y?
>
> The value is accessed address minus $F000
> The address to write to is the address that is accessed 3 or 4 cycles after
> the access to $F0xx.
> >>
>
>OK, lets look at the following
>
>cmp 1000
>nop
>lda (2000),y // don't worry about the nonsense addresses
> // at location 2000 is 1234 stored
> // y=6
>
>is that like a BASIC:
>
>poke 0,2000
>poke 0,2006
>poke 0,1240
>?
It would be Type Mismatch Error, because indirect-y addressing only works
when the pointer is stored in the zeropage. But if you do
CMP $F000,X
CMP ($80),Y (no NOP, because this addressing mode takes more cycles)
it would write the value stored in X to address 1240.
Ciao, Eckhrad Stolberg
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