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From: amos@instable.UUCP (Amos Shapir)
Newsgroups: comp.lang.c
Subject: Re: Long Branches
Message-ID: <672@instable.UUCP>
Date: Tue, 20-Jan-87 02:00:06 EST
Article-I.D.: instable.672
Posted: Tue Jan 20 02:00:06 1987
Date-Received: Tue, 20-Jan-87 23:33:01 EST
References: <3950006@nucsrl.UUCP> <6552@alice.uUCp>
Reply-To: amos%nsta@nsc.com (Amos Shapir)
Organization: National Semiconductor (Israel) Ltd.
Lines: 14

A portable kludge solution to the problem: the VAX BSD compiler
generates 'casel' instructions only for switches in which the value range
is dense, i.e. there are a lot of used values between the highest and lowest
case values (I think the criterion is (hi-lo)/nused>=1/3 ).
Otherwise, it generates a set of if's, creating in effect a binary search tree.
If you add a dummy case with a value that is way out of the range, if's
should be created instead of a casel.
After that, if the branches are still too long, just do 'sed s/brw/jmp/'
on the assembly file.
-- 
	Amos Shapir
National Semiconductor (Israel)
6 Maskit st. P.O.B. 3007, Herzlia 46104, Israel
(011-972) 52-522261  amos%nsta@nsc 34.48'E 32.10'N