From mboxrd@z Thu Jan  1 00:00:00 1970
From: Graeme Russ <graeme.russ@gmail.com>
Date: Tue, 30 Aug 2011 19:37:49 +1000
Subject: [U-Boot] [RFC PATCH] Pre-console buffer for ARM
In-Reply-To: <20110830092934.24BF118C46FC@gemini.denx.de>
References: <1314638517-20178-1-git-send-email-sjg@chromium.org>
	<201108291610.31528.vapier@gentoo.org>
	<CALButCKcoOq8L=adPcJhT5_C_2ftcKfWo7yYBdZm07rf2R+BDQ@mail.gmail.com>
	<201108292132.32574.vapier@gentoo.org>
	<CALButCJF1p+60WOLtiJqhcAed-71VxmP2mBqY2wdNURPk5=Q+g@mail.gmail.com>
	<20110830051710.225A118C46FC@gemini.denx.de>
	<CALButC+t=OUL9XgQnfyAdZmgPJRp7mdRwEE9LKogYHEg1D+m4g@mail.gmail.com>
	<20110830092934.24BF118C46FC@gemini.denx.de>
Message-ID: <4E5CAF6D.5070905@gmail.com>
List-Id: <u-boot.lists.denx.de>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: u-boot@lists.denx.de

Hi Wolfgang,

On 30/08/11 19:29, Wolfgang Denk wrote:
> Dear Graeme Russ,
> 
> In message <CALButC+t=OUL9XgQnfyAdZmgPJRp7mdRwEE9LKogYHEg1D+m4g@mail.gmail.com> you wrote:
>>
>>> If you want to support arbitrary buffer sizes, then just use
>>>
>>>        #define CIRC_BUF_IDX(idx) ((idx) % CONFIG_SYS_TMP_CON_BUF_SZ)
>>
>> I know, but I was concerned that you wouldn't like the use of modulo
>> arithmetic for every putc() - But I suppose thats cheaper than a compare
>> plus branch...
> 
> Well, the difference of "i & (CONFIG_SYS_TMP_CON_BUF_SZ-1)" versus
> "i % CONFIG_SYS_TMP_CON_BUF_SZ" is 1 versus 4 assembler instructions
> on Power, and 2 versus 5 assembler instructions on ARM.  I think we
> can tolerate this.

And it's only hit during printf() before console is initialised :)

Respinning now

Regards,

Graeme