Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!oliveb!tymix!antares!jms
From: jms@antares.UUCP (Joe Smith)
Newsgroups: comp.sys.amiga
Subject: Re: Mixing C with AmigaBASIC
Summary: AmigaDOS exeuctables require special loader
Message-ID: <444@antares.UUCP>
Date: 26 Apr 89 01:46:32 GMT
References: <13680@louie.udel.EDU>
Reply-To: jms@antares.UUCP (Joe Smith)
Organization: Tymnet QSATS, San Jose CA
Lines: 28

In article <13680@louie.udel.EDU> LIZAK98%SNYBUFVA.BITNET@cornellc.cit.cornell.edu (WE DISENGAGE--WE TURN THE PAGE) writes:
>  I did rewrite the serial I/O into C, but an having a hell
>of time getting it to load.  I know I have to load the ML code
>into an array and go from there...

Your code assumes that programs that can be called from the CLI are:
1) position independent (so they can be loaded anywhere in memory and run)
2) consist on nothing but executable code (so CALL CODE%) works).

Neither assumption is true.  Executable commands are stored in files that
have several hunks, including relocation information.  You told it to
jump into the middle of the header where it executed an illegal instruction.

Unlike some 8-bit Operating System (such as C64, CP/M, etc), executable files
are not loaded into memory verbatim and run.  The loader has to do 16 and
32-bit relocations and link the segments together.  To get information into
memory properly, you will have to learn about FD files, you will have to open
the Exec and DOS libraries, you will have to use the LoadSeg function, and you
will have to convince BASIC to put the right stuff in the registers when it
calls your code.

You will need the AmigaDOS Reference Manual and the RKM/Exec (or the
equivalant information from Rob Peck's books) for your project.
-- 
Joe Smith (408)922-6220 | jms@antares.Tymnet.COM or jms@tymix.Tymnet.COM
McDonnell Douglas FSCO  | UUCP: ...!{ames,pyramid}!oliveb!tymix!antares!jms
PO Box 49019, MS-D21    | PDP-10:JMS@F74.Tymnet.COM  CA license plate:"POPJ P,"
San Jose, CA 95161-9019 | narrator.device: "I didn't say that, my Amiga did!"