Z80 Divide by 10

[Eric J Korpela]

On Jan 29, 2008 7:35 AM, Jim Leonard <trixter at oldskool.org> wrote:
> Eric J Korpela wrote:
> > Lack of load immediate into segment isn't a big problem.  Lack of "add
> > immediate to effective address" is a much bigger problem.
>
> Isn't that handled by ADD SI,immed?

That adds an immediate value to the offset portion of an effective
address without changing the segment portion.  There should have been
an  ADD DS:SI,immed instruction.  To do long pointer arithmetic you
end up doing something like...

MOV AX,DS
ADD SI,immed
MOV BX, SI
MOV CL, 4
SAR BX,CL
ADD AX,BX
AND SI,0Fh
MOV DS,AX