49 lines
1.7 KiB
C
49 lines
1.7 KiB
C
/***************************************************************************
|
|
* __________ __ ___.
|
|
* 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;
|
|
}
|