Subject: Re: HEADS UP: migration to fully dynamic linked "base" system
To: Bill Studenmund <email@example.com>
From: Michael L. Hitch <firstname.lastname@example.org>
Date: 08/26/2002 21:27:55
On Mon, 26 Aug 2002, Bill Studenmund wrote:
> On Mon, 26 Aug 2002, Matt Fredette wrote:
> > I guess I could try to finish it up, but one thing that always discouraged
> > me about 68000 PIC is the limited process address space: only 16MB total.
> Is that due to the ABI or what?
> [I think this is Motorola ASM syntax]
> MOVE #$12345678, d0
> LEA (0, PC, D0), a0
> will give you a 32-bit offset relative to the PC, won't it?
Not really, it will give you a 24-bit offset relative to the PC with
"garbage" bits in the upper 8 bits that will be ignored. [Or useful to
Microsoft to keep a byte value in pointers stored in memory and breaking
the program when upgrading to a a CPU with real 32 bit addressing :-)]
The 68000/68010 only has a 24 bit address bus.
Michael L. Hitch email@example.com
Information Technology Center
Montana State University Bozeman, MT USA