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To: linux-kernel@vger.kernel.org
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: 2.4 kernel & gcc code generation: a bug?
Date: 6 Feb 2001 23:46:28 -0800
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Followup to:  <3A8108F8.2476.21D0F5@localhost>
By author:    "Ulrich Windl" <Ulrich.Windl@rz.uni-regensburg.de>
In newsgroup: linux.dev.kernel
> 
> You'll notice that %edx is not pushed at the start of the function. 
> Unless the caller saves that, edx will be spilled. Depending on the 
> level of optimization this can be bad. Am I wrong?
> 

Yes.  %eax, %edx and %ecx are defined as caller-saved registers.  Each
function is free to clobber them at will.

Now, if you saw the same for %ebx, %ebp, %esi or %edi, that would be
bad.

	-hpa
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