[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [f-cpu] more about f-romfs



hi,

Christophe wrote:
> > > Par example the Motorola 68302 (communication-processor) init-process is
> > > in short:
> > >
> > > 1. set BAR (basis adress register)
> > > 2. define with base and mask the RAM/ROM/Port-areas, means the
> > > chip-selects
> > > 3. Code will be executed from CS0, means ROM at adress 0
> > > 4. define the stackpointer
> > > 5. define IRQ-tables
> > > 6. test RAM
> >
> > i don't understand : you start executing code (1 and 2)
> > but 3 means that code starts execution somewhere else (?)
> > or i have missed a point.
> 
> Not very clear in fact...  I think it would be better something like that :
> 
> 1.starts at 0x0 (area 0 - /cs0) which is in fact mapped to a ROM as an internal
> or external space memory.

sure but then, how do you define the ROM address ? Andreas says that this
range is defined by a set of registers which must be programmed ...
yet another chicken-and-egg problem :-)

> 2.sets BAR, selects the right chip-selects for RAM/ROM/Ports areas.
> 3.tests RAM.
> 4.defines the stack pointer and IRQ-tables.


WHYGEE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*************************************************************
To unsubscribe, send an e-mail to majordomo@seul.org with
unsubscribe f-cpu       in the body. http://f-cpu.seul.org/