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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2004 by Jens Arnold
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "sdmmc.h"
/* helper function to extract n (<=32) bits from an arbitrary position.
counting from MSB to LSB */
unsigned long card_extract_bits(
const unsigned long *p, /* the start of the bitfield array */
unsigned int start, /* bit no. to start reading */
unsigned int size) /* how many bits to read */
{
unsigned int long_index, bit_index;
unsigned long result;
/* we assume words of CSD/CID are stored most significant word first */
start = 127 - start;
long_index = start / 32;
bit_index = start % 32;
result = p[long_index] << bit_index;
if (bit_index + size > 32) /* crossing longword boundary */
result |= p[long_index+1] >> (32 - bit_index);
result >>= 32 - size;
return result;
}
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