Re: Question about 65816

From: Andre Fachat (
Date: 1998-07-09 09:36:55

Ethan Dicks wrote:
> define a double-BRK as a noop or a call to the monitor.  With this scheme,
> you don't have to worry about kernel jump tables in ROM or any of that ugly
> stuff.  Porting to a different 6502 design is a matter of hardware specific
> routines and a vector table that is known to the interrupt handler.

Yes, but IMHO the BRK instruction is slow. Together with getting the
vector from the BRK address on the stack, then jumping to this address,
with saving registers along the way (during the vector get) etc.
This is _much_ slower than a simple jump table. 

<self-plug> And my relocatable file format easily allows 'late-binding',
i.e. relocation of jump tables for example at load time </self-plug>


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Andre Fachat, Institute of physics, Technische Universitšt Chemnitz, FRG
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