[Coco] Any reason to put a 6309 in a Coco2?

Roger Taylor rtaylor at bayou.com
Fri Jan 2 02:45:28 EST 2004


At 03:27 PM 1/1/2004 -0700, you wrote:
>LDA #$4F (machine code: 864F)
>
>Suppose that is at $3F00. Now if you jump to $3F01, you actually start at
>the byte with $4F in it. $4F just happens to be CLRA. The processor has no
>idea that it's really part of the LDA instruction, nor does it care. And
>no illegal opcodes are executed.

$4F is the operand, actually.  The only "opcodes" that come to mind that 
you can really jump in the middle of, so to speak, is $10xx and $11xx.  And 
you're right, some very nice tricks can be achieved to save both time and 
space.


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Roger Taylor






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