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Re: [avr-libc-dev] Re: Far addresses in flash
From: |
John Devereux |
Subject: |
Re: [avr-libc-dev] Re: Far addresses in flash |
Date: |
03 Jun 2005 18:16:37 +0100 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.4 |
Paul Schlie <address@hidden> writes:
> > From: "E. Weddington" <address@hidden>
> >> Björn Haase wrote:
> >> A real solution of the issue would, IMO, require that someone adds
> >> functionality for supporting different memory spaces within gcc's C/C++
> >> front-end and gcc's mid-end.
> >>
> > You're right, that's the best, and most needed solution.
> > However, *is* it possible to have 24-bit pointers in GCC
> > (as opposed to 32-bit)? How difficult would that be?
>
> - Likely not worth it, as GCC also presumes data to be aligned on
> power-of-two unit boundaries, and it doesn't address the multiple address
> space issues raised by Björn.
>
> Personally, I believe the single largest obstacle associated with the
> use of GCC for any reasonably serious AVR development is the fact that
> presently complex literal data can quickly consume AVR's relatively small
> RAM (as all data is presumed to be accessible from there), although
> intermediate asm helper routines may be used to explicitly access other
> memory spaces explicitly (or as Björn has also previously suggested, a
> set of C++ pointer classes may be defined and utilized to hide the asm
> routines within, thereby enabling the declaration of smart pointer classes
> external to the compiler's implementation to abstract access to multiple
> address spaces, which helps, but still requires that literal data be
> declared and used in only limited ways, as otherwise will unnecessarily
> still consume AVR's typically limited RAM.)
Agree emphatically. It would be really great if gcc could do this.
--
John Devereux
- [avr-libc-dev] Re: Far addresses in flash, Per Arnold Blåsmo, 2005/06/02
- Re: [avr-libc-dev] Re: Far addresses in flash, Björn Haase, 2005/06/02
- Re: [avr-libc-dev] Re: Far addresses in flash, E. Weddington, 2005/06/02
- Re: [avr-libc-dev] Re: Far addresses in flash, Paul Schlie, 2005/06/02
- Re: [avr-libc-dev] Re: Far addresses in flash, E. Weddington, 2005/06/02
- Re: [avr-libc-dev] Re: Far addresses in flash, Paul Schlie, 2005/06/02
- Re: [avr-libc-dev] Re: Far addresses in flash, Paul Schlie, 2005/06/02
- Re: [avr-libc-dev] Re: Far addresses in flash, Björn Haase, 2005/06/03
- Re: [avr-libc-dev] Re: Far addresses in flash,
John Devereux <=