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From: henry@ginger.sri.com (Henry Pasternack)
Newsgroups: comp.sys.m68k
Subject: Re: Getting started with the m68k.
Message-ID: <14237@unix.SRI.COM>
Date: 16 Jul 90 22:26:21 GMT
Sender: news@unix.SRI.COM
Reply-To: henry@ginger.sri.com (Henry Pasternack)
Organization: SRI International
Lines: 23


   Thank you to everyone who responded to my request for help with
my single-board 68000 system.  As usual, I have received a lot of
helpful suggestions.

   After some screwing around, I figured out how to use the Sun
C compiler to generate ROMable code.  It turned out to be fairly
easy.  I'm using a simple routine in assembly to put the reset
vector stuff at the bottom of my ROM (ROM is mapped to zero for
the first four reads after reset), followed by a jump to '_main.'
I link this in with my compiled C code, and 'ld' it with a
starting address corresponding to the bottom of ROM, 0xf00000.
Very straightforward.

   After a terribly frustrating evening during which my board
did nothing but halt (I failed to realize that setting the stack
pointer to 0x7ffff would result in a misaligned operand trap after
a 'jsr') I have succeeded in getting a C-language serial test
program running.  When I have the time, I'm going to put my mind
to writing a loader so I can save wear and tear on my EPROM
sockets.

-Henry