Path: utzoo!mnetor!uunet!husc6!bbn!uwmcsd1!ig!agate!ucbvax!CORY.BERKELEY.EDU!dillon
From: dillon@CORY.BERKELEY.EDU (Matt Dillon)
Newsgroups: comp.sys.amiga
Subject: Re: Structure alignment in Manx C
Message-ID: <8802141808.AA27862@cory.Berkeley.EDU>
Date: 14 Feb 88 18:08:02 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 32


>>dillon@CORY.BERKELEY.EDU (Matt Dillon) writes:
>>> > (Manx don't put longword entities on longword boundaries . . .)
>>> 	It might not be preferable, but can hardly be called a bug.  
>>> Remember that warning a lonnngg time ago about declaring such items as
>>> FileInfoBlocks auto?  You can't for the very reason that they require
>>> longword alignment and since longwords don't, no assumption can be made
>>> as to the alignment the compiler used.
>>
>>Any compiler for a 68000/68020 machine, that does not do everything
>>reasonable to put longword structures on longword boundaries, is buggy.
>>Period.  The Amiga is most certainly a 68000/68020 machine.  I wonder
>>how much slower those 68020 machines run because all of the Manx
>>compiled commercial software (at least those with 16-bit ints) don't
>>have their longwords aligned correctly?

	I wouldn't mind seeing a compile time option to fix the problem,
but there are just as many reasons for NOT wanting them on longword boundries.

	You might want a more compact structure.

	C-A sure did, and...

	If you were to make longword alignment the default, your C compiler
would suddenly become totally incompatible with almost every Amiga structure
in existance.

	For example:  struct Menu, &menu.MenuName relative to &menu.NextMenu
is on a word boundry.  struct MenuItem, Node, Message, and thus IORequest,
IOStdReq, etc.....

					-Matt