From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aitor Garcia Subject: enquiry about 4 bpp frame buffer with nibbles swapped Date: Tue, 20 Feb 2007 04:11:56 -0800 (PST) Message-ID: <20070220121156.41538.qmail@web51601.mail.yahoo.com> Reply-To: linux-fbdev-devel@lists.sourceforge.net Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.91] helo=mail.sourceforge.net) by sc8-sf-list1-new.sourceforge.net with esmtp (Exim 4.43) id 1HJTqm-0006sX-Ow for linux-fbdev-devel@lists.sourceforge.net; Tue, 20 Feb 2007 04:12:04 -0800 Received: from web51601.mail.yahoo.com ([206.190.38.206]) by mail.sourceforge.net with smtp (Exim 4.44) id 1HJTqk-0002c8-8F for linux-fbdev-devel@lists.sourceforge.net; Tue, 20 Feb 2007 04:12:04 -0800 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-fbdev-devel-bounces@lists.sourceforge.net Errors-To: linux-fbdev-devel-bounces@lists.sourceforge.net To: linux-fbdev-devel@lists.sourceforge.net Hi all, I am trying to design a 4 bpp FB driver for iMX1 using imxfb.c code as an starting point. The problem that I have found is that MX1 video memory is organised as follows: b7 b6 b5 b4 --> pixel 0. b3 b2 b1 b0 --> pixel 1. The software that I'm using to display things (Qtopia Core) assumes a different scheme of memory to pixel mapping: b7 b6 b5 b4 ---> pixel 1. b3 b2 b1 b0 ---> pixel 0. The solution to overcome this problem is apparently easy: #define SWAP_NIBBLES(in,out) (out=((in&0xf)<<4) | ((in&0xf0)>>4) |\ ((in&0xf00)<<4) | ((in&0xf000)>>4) |\ ((in&0xf0000)<<4) | ((in&0xf00000)>>4) |\ ((in&0xf000000)<<4) | ((in&0xf0000000)>>4)) But I do not know where to do it. Frame Buffer has 3 functions cfb_fillrect, cfb_copyarea and cfb_imageblit which I thought were the key to solve my problems but Qtopia Core does not make use of them. imxfb_map_video_memory function or fb_mmap, seem to be good candidates but I do not know how to progress further. I would be very grateful if I could receive some kind of help. Best wishes, Aitor ____________________________________________________________________________________ It's here! Your new message! Get new email alerts with the free Yahoo! Toolbar. http://tools.search.yahoo.com/toolbar/features/mail/ ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV