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- #ifndef _BITS_BITOPS_H
- #define _BITS_BITOPS_H
-
- /** @file
- *
- * ARM bit operations
- *
- */
-
- FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
- #include <stdint.h>
-
- /**
- * Test and set bit atomically
- *
- * @v bit Bit to set
- * @v bits Bit field
- * @ret old Old value of bit (zero or non-zero)
- */
- static inline __attribute__ (( always_inline )) int
- test_and_set_bit ( unsigned int bit, volatile void *bits ) {
- unsigned int index = ( bit / 64 );
- unsigned int offset = ( bit % 64 );
- volatile uint64_t *qword = ( ( ( volatile uint64_t * ) bits ) + index );
- uint64_t mask = ( 1UL << offset );
- uint64_t old;
- uint64_t new;
- uint32_t flag;
-
- __asm__ __volatile__ ( "\n1:\n\t"
- "ldxr %0, %3\n\t"
- "orr %1, %0, %4\n\t"
- "stxr %w2, %1, %3\n\t"
- "tst %w2, %w2\n\t"
- "bne 1b\n\t"
- : "=&r" ( old ), "=&r" ( new ), "=&r" ( flag ),
- "+Q" ( *qword )
- : "r" ( mask )
- : "cc" );
-
- return ( !! ( old & mask ) );
- }
-
- /**
- * Test and clear bit atomically
- *
- * @v bit Bit to set
- * @v bits Bit field
- * @ret old Old value of bit (zero or non-zero)
- */
- static inline __attribute__ (( always_inline )) int
- test_and_clear_bit ( unsigned int bit, volatile void *bits ) {
- unsigned int index = ( bit / 64 );
- unsigned int offset = ( bit % 64 );
- volatile uint64_t *qword = ( ( ( volatile uint64_t * ) bits ) + index );
- uint64_t mask = ( 1UL << offset );
- uint64_t old;
- uint64_t new;
- uint32_t flag;
-
- __asm__ __volatile__ ( "\n1:\n\t"
- "ldxr %0, %3\n\t"
- "bic %1, %0, %4\n\t"
- "stxr %w2, %1, %3\n\t"
- "tst %w2, %w2\n\t"
- "bne 1b\n\t"
- : "=&r" ( old ), "=&r" ( new ), "=&r" ( flag ),
- "+Q" ( *qword )
- : "r" ( mask )
- : "cc" );
-
- return ( !! ( old & mask ) );
- }
-
- /**
- * Set bit atomically
- *
- * @v bit Bit to set
- * @v bits Bit field
- */
- static inline __attribute__ (( always_inline )) void
- set_bit ( unsigned int bit, volatile void *bits ) {
-
- test_and_set_bit ( bit, bits );
- }
-
- /**
- * Clear bit atomically
- *
- * @v bit Bit to set
- * @v bits Bit field
- */
- static inline __attribute__ (( always_inline )) void
- clear_bit ( unsigned int bit, volatile void *bits ) {
-
- test_and_clear_bit ( bit, bits );
- }
-
- #endif /* _BITS_BITOPS_H */
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