Re: Questions about trampolines

[Robert Dewar <dewar at adacore dot com>]

Michael N. Moran wrote:
> Robert Dewar wrote:
>
> > Michael N. Moran wrote:
> >
> > > The AVR is a bit more extreme than the Harvard arch you're describing.
> > > The AVR has completely separate address spaces for instructions and
> > > data. Instruction data space cannot be accessed through a data space
> > > pointer. There are separate instructions for accessing instruction
> > > and data space.
> >
> >
> >
> > But there must be a way to write stuff into the instruction data
> > space, or how would you load code? So you just have to setup an
> > auxiliary stack in code space.
>
>
> The AVR is an embedded processor, and the instruction space is
> is Flash *not* RAM. We're not talking about a system that loads
> programs at run-time.

In that case, you have to use function descriptors I think there
is no way around this.
> These devices typically have a "large" amount of Flash ROM
> (32K-68K bytes), and a smaller amount of RAM (512-2K bytes).
> Don't hold me to these numbers, but you get the idea.