Re: LZ: Info about processor in Ti-85 required


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Re: LZ: Info about processor in Ti-85 required



> > What kind of processor is used in the TI-85.  It is not a Zilog Z80,
> > since it is made by Toshiba.  But it is at least compatible to a
> > certain degree to the Z80.  Does the TI-85 processor support the full
> > instruction set of the Z80?  Does it support any instructions that aren't
> > in the Z80 instruction set?
> True, the cpu is not a ZILOG z80, but it is a z80, it's just a copy 
> made by Toshiba.  It's exactly the same instructions and all.  There 
> are some undocumented commands, but I wouldn't use those(I think sls 
> was the one I remember)
Then it is not a z80.  It maybe z80 compatible, but it isn't a z80.
How do you know that it has exactly the same insturctions?  How do 
you know that there are undocumented commands?  Do you have 
documentation from Toshiba?
 
> > Also what is the word size of this processor? 8-bit?
>Memory addresses are 16-bit
Yes I know it has 16 bit addressing.  But what is its word size?
The address size is not always the same as the word size.


> There is an R register, but I wouldn't use it unless you disable the 
> interupts, but why would you want to?  You got enough registers and 
> stack space and memory
The R register holds the value of the current row (or is it column) 
address of the ram that is being refreshed.  It would be incremented every 
instruction if it is implemented on this processor.  Hence I was 
thinking it would be a good way to get a random number, or at least 
quite a good seed for a random number routine.
-----
Richard Gallagher
rbg@cvm.co.nz


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