linux-kernel - [PATCH] Make shr to divide by power of 2

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Message-ID: <20090806180930.GA3004@localdomain.by>
Date:	Thu, 6 Aug 2009 21:09:30 +0300
From:	Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH] Make shr to divide by power of 2

Hello Andrew,

drivers/video/console/bitblit.c
'shr' is used to divide by 8 except 'static void bit_putcs'.

Of course, compiler supposed to do something like
	add    $0x7,%eax
	shr    $0x3,%eax
instead of div. Should we rely on this?
============

Make an arithmetic right shift to divide by power of 2.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
---
diff --git a/drivers/video/console/bitblit.c b/drivers/video/console/bitblit.c
index 69864b1..b816151 100644
--- a/drivers/video/console/bitblit.c
+++ b/drivers/video/console/bitblit.c
@@ -144,7 +144,7 @@ static void bit_putcs(struct vc_data *vc, struct fb_info *info,
 		      int fg, int bg)
 {
 	struct fb_image image;
-	u32 width = (vc->vc_font.width + 7)/8;
+	u32 width = (vc->vc_font.width + 7) >> 3;
 	u32 cellsize = width * vc->vc_font.height;
 	u32 maxcnt = info->pixmap.size/cellsize;
 	u32 scan_align = info->pixmap.scan_align - 1;

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