Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!wuarchive!uunet!cbmvax!carolyn
From: carolyn@cbmvax.commodore.com (Carolyn Scheppner - CATS)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: How are registers assigned to C functions args ?
Message-ID: <22409@cbmvax.commodore.com>
Date: 13 Jun 91 17:08:31 GMT
References: <1991Jun10.080025.27797@eso.org>
Reply-To: carolyn@cbmvax.commodore.com (Carolyn Scheppner - CATS)
Organization: Commodore, West Chester, PA
Lines: 29

In article <1991Jun10.080025.27797@eso.org> lzago@eso.org (Lorenzo Zago) writes:
>I am trying to write a shared library callable both in AmigaBasic and C.
>Because I am very poor in assembler I wish to write all the library 
>functions in C.
>[]
>However, when in my library functions there is a call to an Intuition
>function, I find that an argument, say a window pointer, is now in a0.
>In order to modify correctly the code generated by LibTool and to write
>the correct .fd file (also required to get the .bmap file for AmigaBasic)
>I need to identify, or better, to define which registers are actually used.


Read the Intro in the RKM Libs and Devs

All system library functions expect longs.

All system library functions, unless specifically documented
  otherwise in their autodoc, trash a0, a1, and d1, and return their
  result in d0 (or trash d0 if they  have no result).

All system library functions expect A6 to contain their library base.

-- 
==========================================================================
 Carolyn Scheppner -- Tech. Mgr. CATS - Commodore Amiga Technical Support
 PHONE 215-431-9180 {uunet,rutgers}!cbmvax!carolyn  carolyn@commodore.com

 Reentrant code - the only way to fly. 
==========================================================================