From: Graeme Russ <graeme.russ@gmail.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [RFC PATCH] Pre-console buffer for ARM
Date: Tue, 30 Aug 2011 19:37:49 +1000 [thread overview]
Message-ID: <4E5CAF6D.5070905@gmail.com> (raw)
In-Reply-To: <20110830092934.24BF118C46FC@gemini.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
next prev parent reply other threads:[~2011-08-30 9:37 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-29 17:21 [U-Boot] [RFC PATCH] Pre-console buffer for ARM Simon Glass
2011-08-29 19:20 ` Mike Frysinger
2011-08-29 19:42 ` Simon Glass
2011-08-29 20:10 ` Mike Frysinger
2011-08-29 23:00 ` Graeme Russ
2011-08-30 1:32 ` Mike Frysinger
2011-08-30 1:49 ` Graeme Russ
2011-08-30 2:50 ` Mike Frysinger
2011-08-30 3:12 ` Graeme Russ
2011-08-30 5:17 ` Wolfgang Denk
2011-08-30 5:28 ` Graeme Russ
2011-08-30 9:29 ` Wolfgang Denk
2011-08-30 9:37 ` Graeme Russ [this message]
2011-08-29 22:49 ` Graeme Russ
2011-08-29 23:01 ` Simon Glass
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