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On Fri, 25 Jan 2002, Richard B. Johnson wrote: > On Fri, 25 Jan 2002, wrote: > > > I am writing a module and would like to perform arithmetic on long > > long variables. When I try to do this the module does not load due > > to the unresolved symbols __udivdi3 and __umoddi3. I notice these > > are normally defined in libc. Is there any way I can do this in a > > kernel module. > > > > Many Thanks > > > > Simon. > > Normally, in modules, the granularity is such that divisions can > be made by powers-of-two. In a 32-bit world, the modulus that you > obtain with umoddi3 (the remainder from a long-long, division) should > normally fit within a 32-bit variable. If you insist upon doing 64-bit > math in a 32-bit world, then you can either make your own procedures > and link them, of you can "appropriate" them from the 'C' runtime > library code, include them with your source, assemble, and link them > in. If 64-bit arithmetics cannot be avoided, the do_div64() macro defined in include/asm/div64.h comes in handy. mod = do_div((unsigned long) x, (long) y) will set x to the quotient x/y and mod to the remainder x%y . Tim - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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