GARTHWILSON wrote:
Welcome.
There's (ZP,X) addressing, and there's (ZP),Y addressing, but no (ZP),X addressing. The 65c02 also has (ZP) addressing (with no indexing), so you don't need X or Y for this.
Thanks for your response, I found this explanation too:
INDIRECT INDEXED ADDRESSING - In indirect indexed addressing (referred to as ( Indirect) , Y), the second byte of the instruction points to a memory location in page zero.
The contents of this memory location is added to the contents of the Y index register, the result being the low order eight bits of the effective address.So this should work:
Location $70 = $40
Location $71 = $59
LDA value to be stored
LDY #0
STA (&70),Y
Which should store data in $5940 (made up from $59$40 with zero offset)
Is that correct?