Path: utzoo!attcan!uunet!husc6!bloom-beacon!mit-eddie!uw-beaver!teknowledge-vaxc!sri-unix!garth!walter
From: walter@garth.UUCP (Walter Bays)
Newsgroups: comp.arch
Subject: Re: separate integer and float register
Message-ID: <1241@garth.UUCP>
Date: 16 Aug 88 18:58:07 GMT
References: <2724@wright.mips.COM> <6800002@modcomp>
Reply-To: walter@garth.UUCP (Walter Bays)
Organization: INTERGRAPH (APD) -- Palo Alto, CA
Lines: 16

In article <6800002@modcomp> joe@modcomp.UUCP writes:
>Special floating point registers also slow down context switching, due
>to the extra time needed to save/restore them.

More registers slow down context switching, whether integer or floating
point, windowed or conventional.  The net effect depends on the
workload; as you point out, some real-time applications may have a very
high context switch rate.  In choosing/designing a real-time executive
for such an application on a machine with many registers I might adopt
register usage conventions that treated most registers as volatile.
-- 
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