Gentoo Archives: gentoo-embedded

From: Jean-Marc Beaune <jm.beaune@×××××.com>
To: gentoo-embedded@l.g.o
Subject: [gentoo-embedded] Atmega issue since reinstallation of cross-avr/gcc
Date: Mon, 24 Oct 2011 19:42:08
Message-Id: CAK7bL3ym8MsJ7wbHDC28a03A8Rkui0zbhvVCW6Qa05pAUgMfLQ@mail.gmail.com
Hi,

Not easy to explain but I'll gi ve a go.

I programed an atmega328p to read temperature and send it via USART. That
worked fine untill I changed my laptop.

After changing my computer (and therefore reinstalling cross-avr/gcc), then
a part of a function used to read the temperature doesn't work anymore, i.e.
it compiles fine but the atmega doesn't send anything via USART, the program
dumps.

I narrowed down the problem and it seems to be a problem when doing some
calculation in a function:

All variables below are declared as uint8_t

The return statement below causes the program to crash:
return (double) temp_LSB - 0.25 + (double)(count_per_c - count_remain) /
count_per_c;

The return statement below causes the program to crash also:
return (double) temp_LSB - 0.25;

The return statement below is OK:
return  (double)(count_per_c - count_remain) / count_per_c;

Since it coincides with a change of computer used to compile the program I
wonder if it could be a missing flag/option for cross-avr/gcc?

Any advice appriciated,
Thank you

-- 
Jean-Marc