Date:	Tue, 2 Feb 1999 20:05:52 -0500
Message-Id:	<199902030105.UAA14606@envy.delorie.com>
From:	DJ Delorie <dj AT delorie DOT com>
To:	djgpp AT delorie DOT com
In-reply-to:	<3.0.6.32.19990202172139.00921a20@pop.netaddress.com> (message
	from Paul Derbyshire on Tue, 02 Feb 1999 17:21:39 -0500)
Subject:	Re: 64-bit integer math
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	<3 DOT 0 DOT 6 DOT 32 DOT 19990202125723 DOT 00904370 AT pop DOT netaddress DOT com>
	<Pine DOT GSO DOT 4 DOT 02 DOT 9902012103100 DOT 16025-100000 AT neptune DOT calstatela DOT edu>
	<3 DOT 0 DOT 6 DOT 32 DOT 19990202125723 DOT 00904370 AT pop DOT netaddress DOT com>
	<3 DOT 0 DOT 6 DOT 32 DOT 19990202150512 DOT 0090dc30 AT pop DOT netaddress DOT com> <3 DOT 0 DOT 6 DOT 32 DOT 19990202172139 DOT 00921a20 AT pop DOT netaddress DOT com>
Reply-To:	djgpp AT delorie DOT com

> Really? "simulating" it? Is there no 64 bit (integer) multiply in the Intel
> alu?

As far as I know, the best it can do is multiply two 32 bit numbers to
get one 64 bit number.  I don't think it can multiply two 64 bit
numbers in a single opcode.

gcc does 64-bit multiplies with one mul, two imuls, and two adds.

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