Re: implementing software unsigned divide

[Jacob Sparre Andersen <sparre@nbi.dk>]

Stephen:

> I'm porting GNAT to a 16 bit microprocessor that does not provide a
> hardware instruction for unsigned divide (it has multiply and signed
> divide, both 16 and 32 bit). Can anyone provide a reference to a book
> that discusses how to do this, and/or an algorithm that does it? I've
> looked in Knuth, and did an initial web search, and haven't found
> anything.

I have heard that there exists a free (Open Source) library for doing
calculations with very long integers. I suppose that you could find
something useful there.

A "cheap" solution could be to limit unsigned integers to the range
0 .. 2**31-1, but I am not sure this is allowed by the LRM.

Jacob
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