[Icc-avr] Calculations

[Glenn Greig]

No compiler error, Bengt.
 
Clearly the correct answer for temp2 is -1 (signed), which is 65535 (unsigned).
 
Glenn

-----Original Message-----
From: icc-avr-bounces at imagecraft.com [mailto:icc-avr-bounces at imagecraft.com]On Behalf Of Bengt Ragnemalm
Sent: January 7, 2008 9:29 AM
To: ICC-AVR discussion list
Subject: [Icc-avr] Calculations



Hi!

 

I have spent some of my spare time during Christmas solving some strange problems I have had with a design. My problems was something completely different but I ended up with this:

 

- I have found a calculation that may be a compiler error.

 

This is my test code, baudrate is 38400:

 

#define F_CPU 7372800


temp2 = F_CPU/(16L*baudrate)-1;    // Normal calculation, result OK
temp2 = 0/(16L*baudrate)-1;    // Results into 65535



I guess that the last calculation error is because of some rounding problem but obviously the correct answer is 0.

 

/Bengt

________________________________________________________________

Bengt Ragnemalm                        Tel +46 13 22 24 97

Research engineer                                       FAX: +46 13 10 19 02

Linköpings Universitet                                 <mailto:bengt.ragnemalm at imt.liu.se> mailto:bengt.ragnemalm at imt.liu.se

Inst. för Medicinsk Teknik Internet:         <http://www.imt.liu.se/> http://www.imt.liu.se

S-581 85 Linköping SWEDEN

 

 

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