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From: d88-jwa@nada.kth.se (Jon Watte)
Newsgroups: comp.sys.mac.programmer
Subject: Re: patching SetPort()
Message-ID: <2975@draken.nada.kth.se>
Date: 19 Feb 90 00:41:16 GMT
References: <Feb.17.20.57.45.1990.11446@topaz.rutgers.edu> <3991@hub.UUCP>
Reply-To: d88-jwa@nada.kth.se (Jon W{tte)
Organization: Royal Institute of Technology, Stockholm, Sweden
Lines: 50

>From article <>, by jjoshua@topaz.rutgers.edu (Jon Joshua):
>> Question:  Could someone please shed some light on what might be
>> happening?  Why only under MF and not finder.  I tried booting with 0
>> INITs/CDEVs etc. and the same thing happened.

In article <3991@hub.UUCP> 6500stom@hub.UUCP (Josh Pritikin) writes:
>I think its better to do it this way:
> 	asm {
>		movem	a0/a1/d0,-(sp)	;save the reg that you use
>		bra.s	@start		;Jump over storage
>	tAddr:	dc.l	0		;Save SetPort trap addr here
>	start:	jsr	main		;Do neat stuff
>		movem	(sp)+,a0/a1/d0
>		move.l	@tAddr,-(sp)	;Load orig SetPort trap addr
>		rts			;Outa' here
>	}


Why bother ? The THINK C linker automagically fixes this for you.
Sort of. When compiling code resources, it sets up storage for
globals, and has a jump instruction at relative location 0 within
the code segment to the functino named main() (This is _always_
the main entry point)

You should really do something like:

long savedAddress;

main()
{
	asm {
		movem	a0/a1/d0,-(sp)
	}

	do_neat_stuff();

	asm {
		movem	(sp)+,a0/a1/d0
		unlk	a6
		move.l  savedAddress,-(sp)
		rts
	}
}

This is my guess...

h+
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