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From: Arnd Bergmann <arnd@arndb.de>
To: Manfred Spraul <manfred@colorfullife.com>
Subject: Re: [PATCH] reduce large stack usage
Date: Sun, 2 Mar 2003 18:07:53 +0100
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On Sunday 02 March 2003 16:26, Manfred Spraul wrote:

> What do you mean with broken? On i386, the function needs 32 byte stack
> + the space for register saving.
> It must be either a gcc bug, or a bug in your detection script - I don't
> see anything special in twofish_setkey.

You are right that the code itself is not broken -- I did not read it 
properly at first. The stack frame gets small if I compile for s390x
with -fno-schedule-insn, so I suppose that optimization does
not work to well on this particular code. I'll try a different compiler
tomorrow.

I can verify the 32 bytes on i386 with both gcc-3.2 and gcc-3.3-snapshot.
However, when compiling i386 twofish with gcc-2.95, I get an 804 bytes
stack frame. Other architectures are probably somewhere in between
i386 and s390x here, so there should be done something about this.

	Arnd <><
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