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Message-ID: <5374C4EE.9040201@freebsd.org>
Date: Thu, 15 May 2014 06:45:18 -0700
From: Nathan Whitehorn <nwhitehorn@freebsd.org>
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To: Justin Hibbits <jhibbits@freebsd.org>, src-committers@freebsd.org, 
 svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject: Re: svn commit: r266116 - head/sys/powerpc/aim
References: <201405150418.s4F4I7q4048799@svn.freebsd.org>
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On 05/14/14 21:18, Justin Hibbits wrote:
> Author: jhibbits
> Date: Thu May 15 04:18:06 2014
> New Revision: 266116
> URL: http://svnweb.freebsd.org/changeset/base/266116
>
> Log:
>    A page mask size is 12-bits, not 11.
>    
>    MFC after:	1 week
>
> Modified:
>    head/sys/powerpc/aim/trap_subr32.S
>
> Modified: head/sys/powerpc/aim/trap_subr32.S
> ==============================================================================
> --- head/sys/powerpc/aim/trap_subr32.S	Thu May 15 03:47:52 2014	(r266115)
> +++ head/sys/powerpc/aim/trap_subr32.S	Thu May 15 04:18:06 2014	(r266116)
> @@ -677,7 +677,7 @@ disitrap:
>   	mtcr	%r31
>   	bt	17,realtrap		/* branch is user mode */
>   	mfsprg1	%r31			/* get old SP */
> -	clrrwi	%r31,%r31,11		/* Round SP down to nearest page */
> +	clrrwi	%r31,%r31,12		/* Round SP down to nearest page */
>   	sub.	%r30,%r31,%r30		/* SP - DAR */
>   	bge	1f
>   	neg	%r30,%r30		/* modulo value */
>

Is it? 4096 bytes is 2^12. The mask is 4096-1, which is 11 bits all 1.
-Nathan