Amiga Boot

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#2800

From: Chuck L. Peterson
Date: Wed, 17 Jan 1990 16:59

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Does anyone actually know how the boot block on the Amiga works?

The RKM Exec manual states that this should return with D0
containing some failure status, and A0 must contain the address
of where to jump to.  Someone mailed me this code:

Id	dc.b "DOS",0
CHKSUM  dc.l $????????? ; checksum for bootblock
ROOTBLK dc.l $370       ; root block

BOOTPRG lea.l resname(pc),a1
	jsr   -96(a6)
	tst.l d0
	beq   error
	move.l d0,a0
	move.l 22(a0),a0
	moveq  #0,d0
ende	rts
error	moveq	#$ff,d0
	bra	ende
resname dc.b "dos.library",0

I assume the "dos.library" is being opened here by calling
-96(a6) with a1 pointing to the library string; then we
are returning back to the Exec ?!?  All I want is to be able
to write a stand-alone boot block which does Reads and Writes
to the floppy with DoIo() requests.  Any hints would be
appreciated.

Chuck L. Peterson
clp@altos.com

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!asuvax!ncar!ames!amdahl!altos!altos86!clp
From: clp@altos86.Altos.COM (Chuck L. Peterson)
Newsgroups: comp.sys.amiga.tech
Subject: Amiga Boot
Message-ID: <168@altos86.Altos.COM>
Date: 17 Jan 90 16:59:11 GMT
Organization: Altos Computer Systems, San Jose, CA
Lines: 31