From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rick Hohensee <humbubba@smarty.smart.net>
Message-Id: <200107131826.OAA09484@smarty.smart.net>
Subject: Re: [9fans] partial-Plan9ification question
To: 9fans@cse.psu.edu
In-Reply-To: <20010713062335.4AFC3199C0@mail.cse.psu.edu> from "David Gordon Hogan" at Jul 13, 2001 02:23:32 AM
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Date: Fri, 13 Jul 2001 14:26:35 -0400
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>
> > gcc varies between architectures, and even from platform to platform,
> > but i think even on the x86 with hardly any registers, some registers are callee-saved.
>
> ebx, esi and edi are callee save under GCC.  ebp is the frame pointer, so
> that one gets preserved too (I've no idea what happens if you compile with
> -fomit-frame-pointer).

I've never had -fomit-frame-pointer break anything. I think maybe it's an
extranaeity for Pascal. Or for if you suddenly decide your GNU C is
Pascal on the fly. i.e. I don't get why it's not the default.

Thanks to replyers fore and aft of this post. Looks like my headers
question is all on me.

Rick Hohensee

>
> This means that in the Plan 9 port of GCC, the system call wrappers
> have to push these four registers, then push copies of all the arguments...
>