[Coco] Re: Re: M.E.S.S. 6309 error

Rodney V Hamilton Rodney_Hamilton at GBRonline.com
Mon Dec 20 03:54:36 EST 2004


In article <6.1.2.0.0.20041219203452.01efa790 at pop.bayou.com>, 
rtaylor at bayou.com says...
>
>Sorry, I posted my snippet while I was still editing.  I was alternating 
>between using A and B for the bit operation command then storing the same 
>register to 1024, and just got ahead of myself and posted it too quick.
>
>However, the bug does exist.

And as Robert gault posted, the bug in the MESS source has already been fixed.
The bitmask macros for the BAND group were incorrect, so all the BAND opcodes
were affected.

>At 01:49 AM 12/19/2004, Roger Taylor wrote:
>> >
>> >        org     3584
>> >start   clra
>> >        clrb
>> >        ldbt    a,7,7,<255
>> >        stb     1024
>> >        rts
>> >        end     start
>>
>>Roger, shouldn't you instead use 'sta 1024' instead of stb?
>>The ldbt instruction was told to modify reg.A after all.
>>
>>   ldbt a,7,7,<255   ==>  1136BFFF
>>   ldbt b,7,7,<255   ==>  11367FFF

And here was MY typo! the above hex codes were reversed.  I did both of them in
the NitrOS9 ASM, but switched the lines while copying.  They should have read:

  ldbt a,7,7,<255   ==>  11367FFF
  ldbt b,7,7,<255   ==>  1136BFFF

-Rodney





More information about the Coco mailing list