[Coco] CoCo 3 MMU test for all
jdaggett at gate.net
jdaggett at gate.net
Mon Jan 21 18:31:20 EST 2008
On 21 Jan 2008 at 17:50, Arthur Flexser wrote:
> You might want to check whether your assembler assembled LDB 0,X and
> LDB ,X using the same postbyte for both, if both gave you $38. I'm
> pretty sure LDB 0,X, if assembled correctly, should have yielded $78,
> same as PEEK does.
>
> Art
How? LDB ,X and LDB 0,X should yield the same results from any
assembler.
Most assemblers should realize that LDB 0,X is indexed mode with no
offset. Even if it does compute an offset it will either be a 5 or 8 bit offset of
zero. The last time a value was added to zero, the value was returned.
Suggesting that a different value is read would imply that the two
instructions are reading from different addresses.
james
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