Stack Pointer Alignment ? (printf float problem)

[eraycanli]

Posted on October 22, 2013 at 17:30

Hello,

I am observing variables of my application with IAR Terminal I/O while debugging.But when trying to printf() float values, like; printf(''%f '', myFloat); Terminal I/O gives %f as output.After checking over internet, crossed that technical note on IAR's support site:

http://supp.iar.com/Support/?note=85413

So, how can I align Stack Pointer in my code at 8 bytes? Thanks already!

[Tesla DeLorean]

Posted on October 22, 2013 at 18:16

It's far more probable that you are linking against a library which doesn't support floating point scanf/printf.

[Tesla DeLorean]

Posted on October 22, 2013 at 18:20

[DEAD LINK /public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/STM32F3%2c%20IAR6.4%20how%20to%20printf%28%29%20floating%20point&FolderCTID=0x01200200770978C69A1141439FE559EB459D7580009C4E14902C3CDE46A77F0FFD06506F5B&currentviews=292]https://my.st.com/public/STe2ecommunities/mcu/Lists/cortex_mx_stm32/Flat.aspx?RootFolder=%2Fpublic%2FSTe2ecommunities%2Fmcu%2FLists%2Fcortex_mx_stm32%2FSTM32F3%2C%20IAR6.4%20how%20to%20printf%28%29%20floating%20point&FolderCTID=0x01200200770978C69A1141439FE559EB459D7580009C4E14902C3CDE46A77F0FFD06506F5B¤tviews=292

[eraycanli]

Posted on October 22, 2013 at 18:34

Thanks for help!

From http://supp.iar.com/FilesPublic/UPDINFO/004916/arm/doc/EWARM_DevelopmentGuide.ENU.pdf

''Choosing formatters for printf and scanf funcitons''

section says;''To use any other formatter than the default (Full), choose Project>Options and selectthe General Options category. Select the appropriate option on the Library optionspage.''Changed settings to Full and now it works!So, are there any disadvantages of this to MCU?

[Tesla DeLorean]

Posted on October 22, 2013 at 18:44

If you don't used floating point, or just don't print out values, you can significantly reduce your code foot-print. This can make a difference if it allows you to keep your code in a lower cost device.