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From: hadeishi@husc4.harvard.edu (mitsuharu hadeishi)
Newsgroups: net.micro.amiga
Subject: Re: Some remarks to AmigaDos.
Message-ID: <545@husc6.HARVARD.EDU>
Date: Wed, 29-Oct-86 12:26:29 EST
Article-I.D.: husc6.545
Posted: Wed Oct 29 12:26:29 1986
Date-Received: Wed, 29-Oct-86 22:19:48 EST
References: <392@ethz.UUCP> <148600179@uiucuxc>
Sender: news@husc6.HARVARD.EDU
Reply-To: hadeishi@husc4.UUCP (mitsuharu hadeishi)
Organization: Harvard Science Center
Lines: 30
Summary: There is one use for BCPL on the Amiga

In <148600179@uiucuxc> Wayne Hamilton writes:
>    now that i've said all that, you can probably just forget most of it.
>BCPL doesn't provide any compelling advantage over C and assembler, so
>there's not much reason to want to write programs with it.  buying the
>book might be a good idea, if you're interested in hacking on the internals
>of AmigaDos.

	Yes, if you want to write an AmigaDOS device driver (not
just an Exec device but an AmigaDOS device) you have to write the
interface code in either BCPL or Assembler that looks like BCPL.
Either way you have to learn about BCPL and its calling conventions,
etc.  So, for example, if someone wanted to write an AmigaDOS device
driver for the clipboard.device (HINT HINT) you would need to write
the glue code in BCPL so you could access it through the filesystem
(i.e., as in fopen("CLP:","r");) in the same manner as a regular file.
This, of course, is a VERY useful thing to do, since almost all programs
access files and so on through AmigaDOS devices rather than directly
through Exec.  (It is unfortunate that we have two levels of devices,
and that you cannot write AmigaDOS drivers in a completely compatible
fashion in C.  This is the design legacy of Tripos.)

				-Mitsu


	wayne hamilton
	U of Il and US Army Corps of Engineers CERL
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