From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Gordon Hogan <dhog@plan9.bell-labs.com>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] partial-Plan9ification question
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Date: Fri, 13 Jul 2001 02:23:32 -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).

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...