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From: briang@sdd.hp.com (Brian Gragg)
Newsgroups: comp.sys.amiga.programmer
Subject: Input handler question
Summary: I'm having trouble getting an input handler to call a C routine.
Keywords: handler input assembly help questions seeking
Message-ID: <1991May28.184358.29226@sdd.hp.com>
Date: 28 May 91 18:43:58 GMT
Organization: Hewlett Packard, San Diego Division
Lines: 66


Hi,  I've been trying to have an input handler call a C subroutine and it's
just not working.  The C program installs the assembly handler just fine.
I've even checked the handler by having it set the ie_Qualifier to shift so
all my keystokes get shifted to upper case, which works fine.  But if I
include a   jsr _myhandler  in the assembly routine, the system crashes.
What am I doing wrong?

I've written a short C program to call an assembly routine which calls a C
routine.  That seemed to work.  Is there something special about the
assembly routine being a handler.

The C routine is just:

struct InputEvent *myHandler( struct InputEvent *ev)
{
  return(ev);
}

The assebly routine is:
        
	
	include "exec/types.i"
        include "exec/io.i"
        include "devices/inputevent.i"
        
        CSECT TEXT

        xdef    _HandlerInterface
        xref    _myhandler

_HandlerInterface:
        LINK    A5,#-16
        move.l  A0,D0
        
        cmp.b   #IECLASS_RAWKEY,ie_Class(a0)
        bne.s   doneit
        
        MOVEM.l A0,-(A7)
        
        JSR     _myhandler

        movem.l (A7)+,A0
doneit:
        UNLK    A5
        rts

        END

I'm somewhat new to C and even newer to assembly (68000 at least).  Is
there a problem if the C program is too large?  Are my compile options
wrong?  I've tried most of them.  

The above routine only crashes the system if the bne.s doneit branch is not
taken.

PLEASE email me any ideas.  I've spent way too much time trying to get this
working!

Thanks in advance,
Brian.

-- 
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  Brian Gragg    briang@sdd.hp.com   hp-sdd!briang  uunet!ucsd!hp-sdd!briang
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