diff options
Diffstat (limited to 'src/VBox/Devices/PC/ipxe/src/arch/arm64/include/bits/bitops.h')
-rw-r--r-- | src/VBox/Devices/PC/ipxe/src/arch/arm64/include/bits/bitops.h | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/src/VBox/Devices/PC/ipxe/src/arch/arm64/include/bits/bitops.h b/src/VBox/Devices/PC/ipxe/src/arch/arm64/include/bits/bitops.h new file mode 100644 index 00000000..4350f622 --- /dev/null +++ b/src/VBox/Devices/PC/ipxe/src/arch/arm64/include/bits/bitops.h @@ -0,0 +1,100 @@ +#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 */ |