diff options
| -rw-r--r-- | include/qemu/bitmap.h | 8 | ||||
| -rw-r--r-- | include/qemu/bitops.h | 172 |
2 files changed, 177 insertions, 3 deletions
diff --git a/include/qemu/bitmap.h b/include/qemu/bitmap.h index 1cf288445f..0044333cb5 100644 --- a/include/qemu/bitmap.h +++ b/include/qemu/bitmap.h @@ -69,6 +69,14 @@ #define DECLARE_BITMAP(name,bits) \ unsigned long name[BITS_TO_LONGS(bits)] +/* + * This is for use with the bit32 versions of set_bit() etc; + * we don't currently support the full range of bitmap operations + * on bitmaps backed by an array of uint32_t. + */ +#define DECLARE_BITMAP32(name, bits) \ + uint32_t name[BITS_TO_U32S(bits)] + #define small_nbits(nbits) \ ((nbits) <= BITS_PER_LONG) diff --git a/include/qemu/bitops.h b/include/qemu/bitops.h index 2c0a2fe751..c7b838a628 100644 --- a/include/qemu/bitops.h +++ b/include/qemu/bitops.h @@ -18,17 +18,48 @@ #define BITS_PER_BYTE CHAR_BIT #define BITS_PER_LONG (sizeof (unsigned long) * BITS_PER_BYTE) +#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) +#define BITS_TO_U32S(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(uint32_t)) #define BIT(nr) (1UL << (nr)) #define BIT_ULL(nr) (1ULL << (nr)) -#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG)) -#define BIT_WORD(nr) ((nr) / BITS_PER_LONG) -#define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long)) #define MAKE_64BIT_MASK(shift, length) \ (((~0ULL) >> (64 - (length))) << (shift)) /** + * DOC: Functions operating on arrays of bits + * + * We provide a set of functions which work on arbitrary-length arrays of + * bits. These come in several flavours which vary in what the type of the + * underlying storage for the bits is: + * + * - Bits stored in an array of 'unsigned long': set_bit(), clear_bit(), etc + * - Bits stored in an array of 'uint32_t': set_bit32(), clear_bit32(), etc + * + * Because the 'unsigned long' type has a size which varies between + * host systems, the versions using 'uint32_t' are often preferable. + * This is particularly the case in a device model where there may + * be some guest-visible register view of the bit array. + * + * We do not currently implement uint32_t versions of find_last_bit(), + * find_next_bit(), find_next_zero_bit(), find_first_bit() or + * find_first_zero_bit(), because we haven't yet needed them. If you + * need them you should implement them similarly to the 'unsigned long' + * versions. + * + * You can declare a bitmap to be used with these functions via the + * DECLARE_BITMAP and DECLARE_BITMAP32 macros in bitmap.h. + */ + +/** + * DOC: 'unsigned long' bit array APIs + */ + +#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG)) +#define BIT_WORD(nr) ((nr) / BITS_PER_LONG) + +/** * set_bit - Set a bit in memory * @nr: the bit to set * @addr: the address to start counting from @@ -225,6 +256,141 @@ static inline unsigned long find_first_zero_bit(const unsigned long *addr, } /** + * DOC: 'uint32_t' bit array APIs + */ + +#define BIT32_MASK(nr) (1UL << ((nr) % 32)) +#define BIT32_WORD(nr) ((nr) / 32) + +/** + * set_bit32 - Set a bit in memory + * @nr: the bit to set + * @addr: the address to start counting from + */ +static inline void set_bit32(long nr, uint32_t *addr) +{ + uint32_t mask = BIT32_MASK(nr); + uint32_t *p = addr + BIT32_WORD(nr); + + *p |= mask; +} + +/** + * set_bit32_atomic - Set a bit in memory atomically + * @nr: the bit to set + * @addr: the address to start counting from + */ +static inline void set_bit32_atomic(long nr, uint32_t *addr) +{ + uint32_t mask = BIT32_MASK(nr); + uint32_t *p = addr + BIT32_WORD(nr); + + qatomic_or(p, mask); +} + +/** + * clear_bit32 - Clears a bit in memory + * @nr: Bit to clear + * @addr: Address to start counting from + */ +static inline void clear_bit32(long nr, uint32_t *addr) +{ + uint32_t mask = BIT32_MASK(nr); + uint32_t *p = addr + BIT32_WORD(nr); + + *p &= ~mask; +} + +/** + * clear_bit32_atomic - Clears a bit in memory atomically + * @nr: Bit to clear + * @addr: Address to start counting from + */ +static inline void clear_bit32_atomic(long nr, uint32_t *addr) +{ + uint32_t mask = BIT32_MASK(nr); + uint32_t *p = addr + BIT32_WORD(nr); + + return qatomic_and(p, ~mask); +} + +/** + * change_bit32 - Toggle a bit in memory + * @nr: Bit to change + * @addr: Address to start counting from + */ +static inline void change_bit32(long nr, uint32_t *addr) +{ + uint32_t mask = BIT32_MASK(nr); + uint32_t *p = addr + BIT32_WORD(nr); + + *p ^= mask; +} + +/** + * test_and_set_bit32 - Set a bit and return its old value + * @nr: Bit to set + * @addr: Address to count from + */ +static inline int test_and_set_bit32(long nr, uint32_t *addr) +{ + uint32_t mask = BIT32_MASK(nr); + uint32_t *p = addr + BIT32_WORD(nr); + uint32_t old = *p; + + *p = old | mask; + return (old & mask) != 0; +} + +/** + * test_and_clear_bit32 - Clear a bit and return its old value + * @nr: Bit to clear + * @addr: Address to count from + */ +static inline int test_and_clear_bit32(long nr, uint32_t *addr) +{ + uint32_t mask = BIT32_MASK(nr); + uint32_t *p = addr + BIT32_WORD(nr); + uint32_t old = *p; + + *p = old & ~mask; + return (old & mask) != 0; +} + +/** + * test_and_change_bit32 - Change a bit and return its old value + * @nr: Bit to change + * @addr: Address to count from + */ +static inline int test_and_change_bit32(long nr, uint32_t *addr) +{ + uint32_t mask = BIT32_MASK(nr); + uint32_t *p = addr + BIT32_WORD(nr); + uint32_t old = *p; + + *p = old ^ mask; + return (old & mask) != 0; +} + +/** + * test_bit32 - Determine whether a bit is set + * @nr: bit number to test + * @addr: Address to start counting from + */ +static inline int test_bit32(long nr, const uint32_t *addr) +{ + return 1U & (addr[BIT32_WORD(nr)] >> (nr & 31)); +} + +/** + * DOC: Miscellaneous bit operations on single values + * + * These functions are a collection of useful operations + * (rotations, bit extract, bit deposit, etc) on single + * integer values. + */ + +/** * rol8 - rotate an 8-bit value left * @word: value to rotate * @shift: bits to roll |