Problem in printf float values in range (-1 value 1)
Hi, We are porting gcc toolchain for a new target. Most of the functionalities are working fine as expected. However, there is one issue regarding the printf function. Issue - Float variables are prefixed by some garbage value in printf function. However, the values are generated correctly when seen through GDB. Ex:- If the expected result is 0.456 RUN OUTPUT - 0.00456 (INCORRECT) GDB OUTPUT - 0.456 (CORRECT) The above issue is observed only with the float variables less than one. i.e. error result if (-1 value 1) The values are displayed correctly if the value does not fall in above range. Ex:- If the expected result is 1.456 RUN OUTPUT - 1.456 (CORRECT) GDB OUTPUT - 1.456 (CORRECT) The above mentioned issue was not observed with gcc-3.4.4. However, on porting to gcc-4.4.1; we are observing this issue. Please let me know if there is anything missing in the port that would possibly result in above incorrect behavior. Thanks Regards, Naveen.H.S www.kpitgnutools.com
Re: Problem in printf float values in range (-1 value 1)
On 18/02/2010 10:11, Naveen H. S wrote: Issue - Float variables are prefixed by some garbage value in printf function. However, the values are generated correctly when seen through GDB. Ex:- If the expected result is 0.456 RUN OUTPUT - 0.00456 (INCORRECT) GDB OUTPUT - 0.456 (CORRECT) The above issue is observed only with the float variables less than one. i.e. error result if (-1 value 1) The values are displayed correctly if the value does not fall in above range. Ex:- If the expected result is 1.456 RUN OUTPUT - 1.456 (CORRECT) GDB OUTPUT - 1.456 (CORRECT) The above mentioned issue was not observed with gcc-3.4.4. However, on porting to gcc-4.4.1; we are observing this issue. It's hard to imagine that this could be some kind of bug in the compiler's argument passing that was causing this effect, much more likely that there's a bug in your libc printf code, possibly some undefined behaviour that has only become a problem because of improvements to the optimisers in series 4; you'll probably have to debug your printf routine to see where it's going wrong. cheers, DaveK
