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Path: utzoo!mnetor!seismo!mimsy!chris
From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.lang.c
Subject: Re: X3J11: Why no labelled loops?
Message-ID: <5707@mimsy.UUCP>
Date: Sun, 8-Mar-87 15:44:48 EST
Article-I.D.: mimsy.5707
Posted: Sun Mar  8 15:44:48 1987
Date-Received: Mon, 9-Mar-87 04:12:28 EST
References: <1710@plus5.UUCP> <388@cognos.UUCP> <545@mntgfx.MENTOR.COM> <674@elrond.UUCP>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 24

:In article <545@mntgfx.MENTOR.COM>, franka@mntgfx.MENTOR.COM (Frank A. Adrian) writes:
:>[Jump tables] would be useful in writing threaded code interpreters
:>and in doing high performance code.

In article <674@elrond.UUCP>, adb@elrond.UUCP (Alan D. Brunelle) writes:
>Would it not be better to use what C already offers? How about implementing
>this with routines rather than goto's? 

This may be unacceptably slow.

>If you declare an array of pointers to functions, then when you have
>your byte_code then:
> 
>(*func)[byte_code](params);
> 
>will do exactly what your want with the added overhead of a procedure
>call. (DON'T flame me on the syntax - look it up....)

And look it up again!  It is (*table[code])(param).  If function
call overhead is not a problem, this works very well for driving
state transition based actions too.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7690)
UUCP:	seismo!mimsy!chris	ARPA/CSNet:	chris@mimsy.umd.edu