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From: bombadil@diku.dk (Kristian Nielsen)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: assembler language
Message-ID: <1991Jun20.095722.25226@odin.diku.dk>
Date: 20 Jun 91 09:57:22 GMT
References: <1991Jun18.848.4216@canrem.uucp>
Sender: bombadil@freja.diku.dk
Distribution: comp
Organization: Department of Computer Science, U of Copenhagen
Lines: 56

david.wyand@canrem.uucp (david wyand) writes:

>The assembler that I'm using is A68K V2.71, and seems to be having a few
>problems with the source.  The original assembler used was apparently
>GENAM2 (never heard of it, myself).  Well, here's the problems...

>rs.l    16*2
>^could this mean reserve 32 long words?  A68K chokes...  Is there an
>easy fix, other than using dc.l 32 times?

>RsReset
>^could this be the same as the EVEN opcode?  If so, an easy fix.

>and finally: __Rs which is just after an equ statement, such as

>Envelope:       equ     __Rs

  The RSRESET and RS.?, and the __RS symbol are special features of the
Hisoft Devpac assembler ('genam2'), They were included to be used for easy
and fast definition of structures, and all the commodore include files can
be converted to use these instead of the LONG/ULONG/UWORD/STRUCT macros.
What you do is, basically:

*
* This structure occurs once for every polygon.
*

* struct polygon

		RSRESET		; reset the special counter __RS to 0.

nrpoint		RS.W	1	;The label 'nrpoint' is set equal to 0.
point1		RS.L	3	;point1 = 2
point2		RS.L	3	;point2 = 14

polygon_sizeof	EQU	__RS	;size of structure.
* the same as 'polygon_sizeof RS.W 0'

So, 'RSRESET' sets __RS to 0. 'label RS.? n' sets label=__RS, and increments
__RS by n bytes/words/longs, in effect reserving 'room' for the structure
entry. At any time, __RS holds the offset for the next field to be defined.
Im not sure about the commodore macros, but the above should be equivalent
to something like

		STRUCTURE	polygon    ;(or STRUCT - don't remember).

		UWORD		nrpoint
		STRUCT		point1,12
		STRUCT		point2,12

Remember to include types.i. And note: This is strictly from memory, you
will have to look up the exact syntax yourself.

	Hope this helps,

	- Kristian.