Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!unmvax!polyslo!rcfische
From: rcfische@polyslo.CalPoly.EDU (Raymond C. Fischer)
Newsgroups: comp.sys.mac.programmer
Subject: Re: -needs68030
Message-ID: <1989Oct24.053554.5622@polyslo.CalPoly.EDU>
Date: 24 Oct 89 05:35:54 GMT
References: <872@cf-cm.UUCP>
Reply-To: rcfische@polyslo.CalPoly.EDU (Raymond C. Fischer)
Organization: Cal Poly State University -- San Luis Obispo
Lines: 37

In article <872@cf-cm.UUCP> ralph@computing-maths.cardiff.ac.uk (Ralph Martin) writes:
>MABuild has flags -needs68030 and -needs68020. I know the 68020 has extra
>instructions compared to the 68000, but didnt realise this was also true of
>the 68030 with respect to the 68020. What exactly are these differences?

Following is what I hope will be the definitive net answer to the question
"What is the difference between the 68020 and 68030".


What the 68030 has that the 68020 doesn't

An on-chip mmu
Additional control registers CRP, SRP, TC, TT0, TT1, MMUSR (all of which
	pertain to the MMU)
New instructions:
	PFLUSH
	PLOAD
	PMOVE
	PTEST
There are additional fields in the cache control register (CACR) to control
the on-chip data cache.


What the 68020 has that the 68030 doesn't:

Two instructions:
	CALLM
	RTM


Of course, there are hardware differences as well, but from the programming
standpoint, this is it.  My reference is the ...
"MC68030 Enhanced 32-Bit Microprocessor User's Manual" by Motorola


Ray Fischer
rcfische@polyslo.calpoly.edu