Re: variable length instructions, Chicken or the Egg?

Walter Banks <walter@bytecraft.com>
19 Oct 2000 14:29:25 -0400

          From comp.compilers
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Re: Chicken or the Egg? michael@moria.de (2000-10-10)
Re: variable length instructions, Chicken or the Egg? joachim_d@gmx.de (Joachim Durchholz) (2000-10-12)
Re: variable length instructions, Chicken or the Egg? rhyde@cs.ucr.edu (Randall Hyde) (2000-10-15)
Re: variable length instructions, Chicken or the Egg? anton@mips.complang.tuwien.ac.at (2000-10-18)
Re: variable length instructions, Chicken or the Egg? walter@bytecraft.com (Walter Banks) (2000-10-19)
| List of all articles for this month |
From: Walter Banks <walter@bytecraft.com>
Newsgroups: comp.compilers
Date: 19 Oct 2000 14:29:25 -0400
Organization: Compilers Central
References: 00-10-073 00-10-084 00-10-110
Keywords: linker

Start long and shorten don't always work. Many processors have
short forms that go only to the current page. As code moves some
jumps and calls suddenly will require long forms to go short a short
distance. The need to lengthen will then break other short jump/calls
and toggling begins. It is a nasty NP-Complete problem for the
code generator


Walter Banks
http://www.bytecraft.com
[Well, sure, I used to program PDP-8's too. But the machines for
which I've done this sort of thing all have relative or absolute
branches of various sizes. -John]


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