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#ifndef _BITS_STRINGS_H
#define _BITS_STRINGS_H
/** @file
*
* String functions
*
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
/**
* Find first (i.e. least significant) set bit
*
* @v value Value
* @ret lsb Least significant bit set in value (LSB=1), or zero
*/
static inline __attribute__ (( always_inline )) int __ffsl ( long value ) {
unsigned long bits = value;
unsigned long lsb;
unsigned int lz;
/* Extract least significant set bit */
lsb = ( bits & -bits );
/* Count number of leading zeroes before LSB */
__asm__ ( "clz %0, %1" : "=r" ( lz ) : "r" ( lsb ) );
return ( 32 - lz );
}
/**
* Find first (i.e. least significant) set bit
*
* @v value Value
* @ret lsb Least significant bit set in value (LSB=1), or zero
*/
static inline __attribute__ (( always_inline )) int __ffsll ( long long value ){
unsigned long high = ( value >> 32 );
unsigned long low = ( value >> 0 );
if ( low ) {
return ( __ffsl ( low ) );
} else if ( high ) {
return ( 32 + __ffsl ( high ) );
} else {
return 0;
}
}
/**
* Find last (i.e. most significant) set bit
*
* @v value Value
* @ret msb Most significant bit set in value (LSB=1), or zero
*/
static inline __attribute__ (( always_inline )) int __flsl ( long value ) {
unsigned int lz;
/* Count number of leading zeroes */
__asm__ ( "clz %0, %1" : "=r" ( lz ) : "r" ( value ) );
return ( 32 - lz );
}
/**
* Find last (i.e. most significant) set bit
*
* @v value Value
* @ret msb Most significant bit set in value (LSB=1), or zero
*/
static inline __attribute__ (( always_inline )) int __flsll ( long long value ){
unsigned long high = ( value >> 32 );
unsigned long low = ( value >> 0 );
if ( high ) {
return ( 32 + __flsl ( high ) );
} else if ( low ) {
return ( __flsl ( low ) );
} else {
return 0;
}
}
#endif /* _BITS_STRINGS_H */
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