Re: A85: Z80 Undocumented Instructions


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Re: A85: Z80 Undocumented Instructions



For the IXh and IXl instructions, you just use something like:
.db $DD / inc h		;increment IXh
.db $DD / inc l		;increment IXl
.db $FD / inc h		;increment IYh
.db $FD / inc l		;increment IYl

the opcodes are the same as for the instructions with hl, except that
the IX instructions are preceded by $DD and the IY by $FD.  I am sure
all of the instructions are slow as molasses like all of the IX and IY
instructions.

-mike pearce

On Sat, 16 Aug 1997 13:35:32 -0500, you wrote:

>Michael Pearce wrote:
>> 
>> Has anyone made an updated "tasm80.tab" file with the IXh, IXl, IYh,
>> and IYl instructions included?
>> 
>> -mike pearce
>
>Undocumented instructions?  What do you mean?!?  For one thing, I
>couldn't find any IXh, IXl, IYh, or IYl instructions in the Z80 user's
>manual.. And why wouldn't Zilog document instructions?  Wouldn't gain
>them anything by leaving them undocumented..
>-- 
>* * * * * * * * * * * * * * * * * * *
>* ~mozart <mozart@technologist.com> *
>* * * * * * * * * * * * * * * * * * *
>


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