Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!mailrus!tut.cis.ohio-state.edu!rutgers!bellcore!tness7!tness1!sugar!ficc!peter
From: peter@ficc.UUCP (Peter da Silva)
Newsgroups: comp.arch
Subject: Re: Self-modifying code
Keywords: self modification, code generation
Message-ID: <1116@ficc.UUCP>
Date: 18 Jul 88 15:08:19 GMT
References: <5254@june.cs.washington.edu> <76700032@p.cs.uiuc.edu> <1110@ficc.UUCP>
Organization: SCADA
Lines: 13

In article <1110@ficc.UUCP>, karl@ficc.UUCP (karl lehenbauer#) writes:
[ about some neat examples of SMC ]

What about the PolyForth scheduler. Each entry in the process table contained
a jump instruction. The next instruction was the save space for the current
PC in a context switch. So a context switch involved jumping to the next
processes process table entry. When a process waited, it put the address of
the next process table entry in that location. This meant that the process
was going to effectively busy-wait, but it's a *very* efficient busy-wait.
For the sort of tight real-time control that PolyForth was designed for, this
was apparently the most efficient way of doing things.
-- 
Peter da Silva  `-_-'  Ferranti International Controls Corporation.
"Have you hugged  U  your wolf today?" (uunet,tness1)!sugar!ficc!peter.