On Sun, Apr 19, 2015 at 9:25 AM, Nilay Vaish <[email protected]> wrote:
> On Sun, 19 Apr 2015, Steve Reinhardt wrote: > > >> ----------------------------------------------------------- >> This is an automatically generated e-mail. To reply, visit: >> http://reviews.gem5.org/r/2743/#review6052 >> ----------------------------------------------------------- >> >> >> I like the restructuring... I agree the micro-op loop is probably not >> realistic. Is there a reason to code a loop in C though, as opposed to >> just using '/' and '%'? >> >> > > The dividend is represented as rdx:rax, which means upto 128 bits of data. > So we would not be able to carry out division by just using '/' and '%' > when only using 64-bit integers. GCC and LLVM both support 128-bit > integers on x86-64 platforms. We may want to use those, but I don't know > if that would cause any compatibility problems. > > -- > Nilay Ah, thanks... I didn't look closely enough to see that it was a 128-bit operation. I'd be fine with using gcc/llvm 128-bit support if others are. If not, there are ways to build a 128-bit operation out of the 64-bit operations that would still be simpler than the bitwise loop. For example, I found this: http://codereview.stackexchange.com/questions/67962/mostly-portable-128-by-64-bit-division and if I read the StackExchange terms correctly, we could just use that code with an appropriate attribution and a link in a comment back to the question (look under Subscriber Content): http://stackexchange.com/legal/terms-of-service Steve _______________________________________________ gem5-dev mailing list [email protected] http://m5sim.org/mailman/listinfo/gem5-dev
