Re: Building gnat-gpl-2011-avr-windows from scratch in GPS

[Brian Drummond <brian@shapes.demon.co.uk>]

On Sun, 15 Apr 2012 09:02:31 -0700, Rolf wrote:

> AVR-Ada V1.1 still uses gcc-4.3.x, AdaCore's AVR compiler is based on
> gcc-4.5. That version has a serious problem if you use locally renamed
> variables of the MCU's registers.  Either use AVR-Ada V1.1 or wait a few
> days/weeks for AVR-Ada V1.2 which will use gcc-4.7

Good news indeed!

I have just successfully(as far as I know!) built gcc-4.7 prerelease 
version (20120302) for AVR, and verified it makes the "Blinky" project 
http://sourceforge.net/apps/mediawiki/avr-ada/index.php?
title=USB_Boarduino#Blinky_in_Ada
which works with appropriate changes on three platforms.

I have also added a switch and modified the example along the lines : 
    Sw : Boolean renames MCU.PinB_Bits(1);
...
    MCU.DDRB_Bits := (1 => DD_Input, others => DD_Output); 
...
        LED <= not Sw;
and the fact that it works as expected suggests to me that the GCC4.5 bug 
with renamed registers has been fixed.

One of the platforms I tried, http://www.pjrc.com/teensy/
uses the Atmega32U4 which isn't in the list of AVRAda 1.1 supported 
devices. (however, mcu=atmega328p worked for this example)
Are there any guidelines how to add support for a new CPU, perhaps by 
modifying the 32u6 sources?

- Brian