Re: Emulating a 64-bit long with only 32 bits: code anyone?

On 30 May 2001 00:21:12 -0400 in article 01-05-087 Sean Luke <seanl@spam.jifsan.is.cs.evil.umd.edu> wrote:
: My apologies if this is a FAQ. I'm designing a Java system for a machine
: that has only 32-bit longs (though it does have 64-bit doubles). I'm
: hoping that someone may know where you can find open source for code which
: manipulates 64-bit longs (multiply, divide, subtract, add, shift, bitwise
: and logical operations, etc.) using only 32 bits, using a structure like


: struct _LONG { int hi, int lo }


: ... as a "long" representation. I believe that Sun's KVM java code has
: stuff like this, but unfortunately Sun's license is too restrictive. ;-(
: Can anyone help here?


Have a look at Donald E. Knuth's MMIXware [1]. There you'll find a
complete C implementation of 64-bit integer and floating-point
arithmetics for 32-bit systems. The code is written in Don Knuth's
literate programming system CWEB and very well documented. As usual
with Don Knuth's code it is in the public domain.


[1] http://www-cs-faculty.stanford.edu/~knuth/mmixware.html)


: Sean Luke


Markus Ackermann


--
Markus Ackermann, Seb.-Kneipp-Weg 6, 89075 Ulm/Donau, +49-731-51451

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