Improve how our printk calls do_div by using constants.

The do_div code has a nice optimization in it when it is called with
constants. The current highly generalized use of it defeats those
optimizations and causes trouble on ARM, resulting in a complex and
buggy code path.

Since we only need to print in bases 8, 10, and 16, do a minor
restructuring of the code so that we call do_div with constants.
If you need base 2, print in base 16 and do it in your head. :-)

This fixes an ongoing problem with ARM, will not harm X86, and will
help PPC should we ever want to support it again.
Plus, I don't have to ever try to understand the div64 assembly and where
it's going wrong :-)

Change-Id: I6a480011916eb0834e05c5bb10909d83330fe797
Signed-off-by: Ronald G. Minnich <>
Tested-by: build bot (Jenkins)
Reviewed-by: David Hendricks <>
Reviewed-by: Stefan Reinauer <>
1 file changed