USBDevice: Silence GCC warning #42
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The following line in USBHAL_KL25Z.cpp would generate a warning in GCC
because of a potential operator precendence issue:
return((USB0->FRMNUML | (USB0->FRMNUMH << 8) & 0x07FF));
This would have been interpreted as:
return((USB0->FRMNUML | ((USB0->FRMNUMH << 8) & 0x07FF)));
since & has higher precedence than |
I switched it to be:
return((USB0->FRMNUML | (USB0->FRMNUMH << 8)) & 0x07FF);
Since it makes more sense to & with 0x7FF after having merged the lower
and upper bytes together rather than just the upper byte. It should
have resulted in the same value either way.
emilmont
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that referenced
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Aug 22, 2013
USBDevice: Silence GCC warning
|
Thanks again! |
|
It is good to cleanup GCC warnings, after having understood (and properly commented like you do) the implications of the change. By the way, could you please also submit a "pull request" to share your GCC warnings setting? Thank you, |
bridadan
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Jun 21, 2016
Fix check on UVISOR_PRESENT=1 macro
SeppoTakalo
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Nov 9, 2016
geky
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Aug 25, 2018
Add support for Travis CI
linlingao
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Jul 12, 2019
Add code to set the prescaler bit count
pan-
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May 29, 2020
Edited the readme a bit
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The following line in USBHAL_KL25Z.cpp would generate a warning in GCC
because of a potential operator precendence issue:
return((USB0->FRMNUML | (USB0->FRMNUMH << 8) & 0x07FF));
This would have been interpreted as:
return((USB0->FRMNUML | ((USB0->FRMNUMH << 8) & 0x07FF)));
since & has higher precedence than |
I switched it to be:
return((USB0->FRMNUML | (USB0->FRMNUMH << 8)) & 0x07FF);
Since it makes more sense to & with 0x7FF after having merged the lower
and upper bytes together rather than just the upper byte. It should
have resulted in the same value either way.