[Coco] ANDCC

[Robert Gault]

I don't know if you would consider EDTASM a macro assembler but with 
EDTASM it would be trivial to create the needed macros.

jdaggett at gate.net wrote:
> On 12 Jun 2007 at 10:25, Ries, Rich (S&FS) wrote:
> 
> 
>>I always found "ANDCC #nn"/"ORCC #nn" to be a royal pain. Why should I
>>need to remember where the various bits are positioned in the micro?
>>Isn't that the type of thing the computer is good at? 
>>
> 
> **************
> 
> The 6800 had a set and clear instruction for three of the 6 bits of the CCR. They 
> were:
> 
> CLI	SEI
> CLC	SEC
> CLV	SEV
> 
> To do so with each bit of the 6809 CCR bits would require 8 instructions. The 
> designers felt that one instruction for clear "ANDCC" and one for SET "ORCC" 
> would be more flexable than having 8 different opcodes. All you have to do is 
> remember to clear you and the appropriate bits with a logic "0". To set you or with 
> a logic "1". 
>  
> 
>>A nice assembler would recognize "SETCC N" or "CLRCC OV" and translate
>>it into the proper hex codes. Honestly, in all my years of micro
>>programming, I cannot remember needing to set or clear more than one
>>bit of the PSW/CC at a time.
>>
> 
> *****************
> 
> Yes it would be nice to  have the assembler torecognize psuedo codes for 
> clearing and setting each bit of the CCR.  Then again you are back to what the 
> designers got away with in the first place. Also you face the potential of  having 
> code that can be assembled by only one assembler. 
> 
> 
> 
>>I guess an "almost nice" assembler would have macros with parameters,
>>to allow creation of SETCC and CLRCC macros.
>>
> 
> That is why it is nice to use a macro assembler.  That way if your heart desires, 
> you write a macro and have at it. 
> 
> james
> 
> 
> 
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