e37044ff1d
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@16637 a1c6a512-1295-4272-9138-f99709370657
46 lines
1.6 KiB
C
46 lines
1.6 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2004 by Jens Arnold
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*
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* All files in this archive are subject to the GNU General Public License.
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* See the file COPYING in the source tree root for full license agreement.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include <stdbool.h>
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#include "config.h"
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#ifdef HAVE_MMC
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#include "ata_mmc.h"
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#else
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#include "hotswap.h"
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#endif
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/* helper function to extract n (<=32) bits from an arbitrary position.
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counting from MSB to LSB */
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unsigned long card_extract_bits(
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const unsigned long *p, /* the start of the bitfield array */
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unsigned int start, /* bit no. to start reading */
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unsigned int size) /* how many bits to read */
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{
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unsigned int long_index = start / 32;
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unsigned int bit_index = start % 32;
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unsigned long result;
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result = p[long_index] << bit_index;
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if (bit_index + size > 32) /* crossing longword boundary */
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result |= p[long_index+1] >> (32 - bit_index);
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result >>= 32 - size;
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return result;
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}
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