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From: Robert Jarzmik <robert.jarzmik@free.fr>
To: Sascha Hauer <s.hauer@pengutronix.de>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH 2/4] introduce region_overlap() function
Date: Fri, 05 Oct 2012 21:55:04 +0200	[thread overview]
Message-ID: <87txu8y9rb.fsf@free.fr> (raw)
In-Reply-To: <1349455505-31731-3-git-send-email-s.hauer@pengutronix.de> (Sascha Hauer's message of "Fri, 5 Oct 2012 18:45:03 +0200")

Sascha Hauer <s.hauer@pengutronix.de> writes:

> To check if two regions overlap
>
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  include/common.h |   13 +++++++++++++
>  1 file changed, 13 insertions(+)
>
> diff --git a/include/common.h b/include/common.h
> index c1f44b4..e30774a 100644
> --- a/include/common.h
> +++ b/include/common.h
> @@ -256,4 +256,17 @@ static inline void barebox_banner(void) {}
>  		(__x < 0) ? -__x : __x;         \
>  	})
>  
> +/*
> + * Check if two regions overlap. returns true if they do, false otherwise
> + */
> +static inline bool region_overlap(unsigned long starta, unsigned long lena,
> +		unsigned long startb, unsigned long lenb)
> +{
> +	if (starta + lena <= startb)
> +		return 0;
> +	if (startb + lenb <= starta)
> +		return 0;
> +	return 1;
> +}
> +
>  #endif	/* __COMMON_H_ */

Or if you look for perfomance (I presume not in barebox) :
static inline bool region_overlap(unsigned long starta, unsigned long lena,
		unsigned long startb, unsigned long lenb)
{
        return starta <= startb + lenb && starta + lena >= startb;
}

It's a bit more obfuscated, but performance wise no branch prediction :)

Cheers.

-- 
Robert

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  reply	other threads:[~2012-10-05 19:55 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-05 16:45 [PATCH] cleanup arm startup a bit Sascha Hauer
2012-10-05 16:45 ` [PATCH 1/4] ARM: add assembly function for setting up C environment Sascha Hauer
2012-10-05 16:45 ` [PATCH 2/4] introduce region_overlap() function Sascha Hauer
2012-10-05 19:55   ` Robert Jarzmik [this message]
2012-10-05 21:33     ` Sascha Hauer
2012-10-06 19:44       ` Robert Jarzmik
2012-10-07  6:59       ` Antony Pavlov
2012-10-05 16:45 ` [PATCH 3/4] ARM: cleanup piggydata copy check Sascha Hauer
2012-10-05 16:45 ` [PATCH 4/4] ARM: simplify start.c Sascha Hauer

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