From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH] Make shr to divide by power of 2
Date: Thu, 6 Aug 2009 21:09:30 +0300 [thread overview]
Message-ID: <20090806180930.GA3004@localdomain.by> (raw)
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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@gmail.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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next reply other threads:[~2009-08-06 18:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-06 18:09 Sergey Senozhatsky [this message]
2009-08-07 6:50 ` [PATCH] Make shr to divide by power of 2 Andi Kleen
2009-08-07 7:42 ` Sergey Senozhatsky
2009-08-08 3:09 ` Robert Hancock
2009-08-08 7:35 ` Andi Kleen
2009-08-09 9:40 ` Sergey Senozhatsky
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