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Re: [using gcc book] 5.20 double-word integers
- From: Gabriel Paubert <paubert at iram dot es>
- To: Chris Devers <cdevers at pobox dot com>
- Cc: GCC list <gcc at gcc dot gnu dot org>
- Date: Tue, 26 Aug 2003 11:52:48 +0200
- Subject: Re: [using gcc book] 5.20 double-word integers
- References: <Pine.OSX.4.56.0308232126560.8695@macdaddy.local>
On Sat, Aug 23, 2003 at 09:33:34PM -0400, Chris Devers wrote:
> Hello again,
>
> In chapter five, section 5.9 (Double-Word Integers) of the _Using GCC_
> book, we have the following sentence:
>
> Multiplication is open-coded if the machine supports
> fullword-to-doubleword a widening multiply instruction.
>
> I feel this would read more clearly if written as follows:
>
> Multiplication is open-coded if the machine supports a
> widening fullword-to-doubleword multiply instruction.
Warning: nitpicking ahead.
On PPC32 at least, there is no widening multiply instruction, but
there is a multiply high instruction which allows to easily compute
all the necessary terms and is used for that purpose.
Regards,
Gabriel