[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 

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. 


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