From: miloody@gmail.com (loody)
To: kernelnewbies@lists.kernelnewbies.org
Subject: about 64-bits division in kernel
Date: Fri, 20 May 2011 11:34:11 +0800 [thread overview]
Message-ID: <BANLkTimGGQgmg+nULVLAUPJ3Z3qj6pgSbg@mail.gmail.com> (raw)
hi all:
My platform is 32-bits cpu and I need following calculation in my driver.
#define longdiv(sr1, sr2, div) (unsigned long )((((unsigned long
long)(sr1) << 32) ^ (sr2)) / (div))
my question are:
1. why "__udivdi3" has any relationship with above calculation?
2. I know the above calculation is implemented in clibc, but why
kernel still implement itself?
why kernel try to make another wheel instead of including what
clib provided ?
--
Regards,
next reply other threads:[~2011-05-20 3:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-20 3:34 loody [this message]
2011-05-20 4:15 ` about 64-bits division in kernel Dave Hylands
2011-05-20 5:51 ` loody
2011-05-20 6:47 ` Dave Hylands
2011-05-21 6:57 ` loody
2011-05-21 7:22 ` Dave Hylands
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