Messages in this thread | | | Date | Tue, 13 Jul 1999 20:48:37 +0200 | From | Jamie Lokier <> | Subject | Re: 64 bit arithmetic in the kernel |
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Michael Richardson wrote: > Is there any easy way to get things like the stuff that it > is in libgcc1.a into the Linux kernel? I have need for 64/32 integer divide > (gcc calls __udivdi3). > This is with 2.2.10, on a Lintel box, and I'm using a module.
Richard Johnson wrote: > Use inline asm. In Intel, you put the high long-word into edx, the low > long-word into eax, and "div" either by an immediate or something in, say > the ecx register. The result is a long-word in eax, with the remainder > in edx. > > This results in an unsigned integer divide, which is what the __udivxxx > means.
Actually __udivdi3 is a 64/64 -> 64 divide, while the "div" instruction is 64/32 -> 32. Apples and pears.
-- Jamie
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