Hi
>>Because R800 executing DJNZ & JR
>>instruction another way for calculating destination address
>
>I don't think so. R800 can execute all Z80 code in the same way as a real
>Z80 does.
>
Then no sense to put 2 processors
I take it from Z80 and R800 Assembly/Machine Language Op-code Tables
Written by "Cyberknight" Masao Kawata.
Revised: 1997-November-19 Wednesday.
The destiny address off-set of all relative jumps is calculated based on the
next address immediately after the jump op-code itself. Thus, a zero off-set
will make the processor jump exactly to the next instruction (it will
execute the next instruction as if no jump was made); a -2 off-set will make
the processor jump back to the jump op-code itself, because all relative
jump op-codes are 2 bytes long, and so on. It is valid also to the DJNZ/DBNZ
instruction.
Valery
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