Re: Questions about trampolines

[Russell Shaw <rjshaw at netspace dot net dot au>]

E. Weddington wrote:
> Michael N. Moran wrote:
>
> > Robert Dewar wrote:
> >
> > > 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.
>
> Right. These address spaces are totally seperate. There is no way to run 
> code in the data space (RAM). One can store some data in the program 
> space (Flash), but it requires special instruction sequences to access it.
>
> <http://www.atmel.com/products/avr/>
>
> > 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.
>
> Code space (Flash): 8K-256K bytes
> Data space (SRAM): 512-8K bytes
> Non-volatile EEPROM: 256-4K bytes (typically half of SRAM, also requires 
> special instruction sequences to access).

How is a pointer to a nested function any different to a pointer to
an un-nested function? Why need trampolines?