Sean Schouten wrote :

> My conclusion was that there must be 
> something messed-up with my usage of the RES function and
> thus my memory addressing. I switched
> to hard coding the address; TEMP_VAR  equ  0x020. That works!

Good debugging practice, but not the best long time solution.

> I am now thinking that using RES does not work without
> having a linker script?

Having a linker script = reloc code.
No linker script = abs code.

And the syntax of the acual code must match.

The syntax for RES in the two "modes" are in
the MPASM/MPLINK manual. But as they says :
"The most common usage for RES is for data
storage in relocatable code."

> Is that a correct assumption? Can anyone point me to 
> good material (tutorial / real world example) on dynamic
> code and / or linker scripts?

The MPASM/MPLINK manual has plenty of examples.

> How does the RES directive  work when the assembler / linker 
> sees that you have a variable that you must access in two banks?
> Does it register that variable in both banks or do you still have to
> pay much attention to bank switching?

Check the MPASM/MPLINK manual.
It depends on which of UDATA, UDATA_ASC, UDATA_OVR and
UDATA_SHR you use.

> Is relocatable ("dynamic") code just as efficient as absolute code?

The difference is i the source code, the processor sees
no difference. Reloc code is often more efficient  to
write and maintain, thought...

Anyway, reloc code isn't much harder to write then abs code,
just a little different. Whichever you learn first, will be
the your natural selection later on.

Jan-Erik.



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