[Tinyos-help] Re: Bug In Arithmetic Ops

[Christophe Braillon]

David Gay a écrit :
> On Nov 26, 2007 2:03 PM, Philip Levis <pal at cs.stanford.edu> wrote:
>   
>> On Nov 26, 2007, at 1:37 PM, Federico Fiorentin wrote:
>>
>>     
>>> I did more tests, and the problem still persists.
>>> It seems that the evaluation becames incorrect when the T1 operand
>>> is bigger then 2^24.
>>>
>>> Below the operands T1, T2.
>>> T1 is the LocalTime.get() value. AlwaysT1 >= T2.
>>>
>>> The subtraction T1-T2  evaluated by mote, T1-T2 by Calc OpenOffice,
>>> then (T1-T2 by mote)-(T1-T2 by Calc) and last one logT1 in base 2.
>>> The same data in the attachment.
>>>
>>> I'll send the code if you need, but I'm sure that there aren't
>>> errors in it.
>>> I hope to find a solution.
>>> thanks
>>>       
>> Can you send the assembly? Just do an avr/msp430-objdump -d to
>> disassemble and send the offending code.
>>     
>
>
> it would be good to see the source code too ;-)
>   
To be sure that it is not the MSP that gives wrong result, why don't you 
try write a program that only does the subtraction, you will easily see 
if it is the microcontroller or you code.

Christophe