Path: utzoo!attcan!uunet!husc6!uwvax!oddjob!uxc!uxc.cso.uiuc.edu!uxe.cso.uiuc.edu!mcdonald
From: mcdonald@uxe.cso.uiuc.edu
Newsgroups: comp.lang.c
Subject: Re: Moving floating point values around
Message-ID: <225800054@uxe.cso.uiuc.edu>
Date: 23 Aug 88 13:13:00 GMT
References: <4256@lynx.UUCP>
Lines: 13
Nf-ID: #R:lynx.UUCP:4256:uxe.cso.uiuc.edu:225800054:000:537
Nf-From: uxe.cso.uiuc.edu!mcdonald    Aug 23 08:13:00 1988


>How naughty would it be for a compiler for the 386/387 (or 286/287 for that
>matter) to move floating-point values with 386 MOV instructions instead
>of FLD and FSTP?  

>Do most compilers do this already, and if so should I assume that I am
>working in a technological backwater?

Microsoft C for the IBM uses string move instructions. Presumably a pure
386 compiler would use those for 64 bit reals and the integer MOV 
instruction for 32 bit ones.
Under the proper condition it will move more than one variable 
in one instruction.