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From: Helge Hafting <helge.hafting@aitel.hist.no>
To: "linux-os (Dick Johnson)" <linux-os@analogic.com>
Cc: Matheus Izvekov <mizvekov@gmail.com>,
	Chris Wedgwood <cw@f00f.org>,
	Christoph Hellwig <hch@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@osdl.org>, Andrew Morton <akpm@osdl.org>,
	Dominik Brodowski <linux@dominikbrodowski.net>
Subject: Re: [RFC PATCH (take #2)] i386: kill CONFIG_REGPARM completely
Date: Tue, 23 May 2006 09:55:16 +0200	[thread overview]
Message-ID: <4472BFE4.8000605@aitel.hist.no> (raw)
In-Reply-To: <Pine.LNX.4.61.0605220739580.26623@chaos.analogic.com>

linux-os (Dick Johnson) wrote:

>On ix86 there are not enough registers to pass a significant parameter
>list all in registers! Like when you are printk()ing a dotted-quad IP
>address, etc. Registers ESI, EDI, and EBX are precious, that leaves
>EAX, ECX, EDX and possibly EBP for only 4 parameters. You need 5
>for the dotted quad IP address. If the compiler were to use the
>precious registers, the contents need to be saved on the stack.
>That negates any advantage to passing parameters in registers.
>  
>
I had the impression that REGPARM in i386 only passed the
first three arguments in registers, putting any further
paramters on the stack? 

Ought to help for all those 3-argument or less functions.

Helge Hafting

  reply	other threads:[~2006-05-23  7:58 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-05-20  2:53 [PATCH] i386: don't consider regparm EXPERIMENTAL anymore Chris Wedgwood
2006-05-20  9:06 ` Christoph Hellwig
2006-05-20 20:13   ` [PATCH] i386: kill CONFIG_REGPARM completely Chris Wedgwood
2006-05-20 21:07     ` Chris Wedgwood
2006-05-20 21:20     ` [RFC PATCH (take #2)] " Chris Wedgwood
2006-05-20 22:00       ` Matheus Izvekov
2006-05-20 23:24         ` Chris Wedgwood
2006-05-22 11:47         ` linux-os (Dick Johnson)
2006-05-23  7:55           ` Helge Hafting [this message]
2006-05-24 20:36           ` H. Peter Anvin
2006-05-29 19:03 ` [PATCH] i386: don't consider regparm EXPERIMENTAL anymore Adrian Bunk

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