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101 lines
3.4 KiB
101 lines
3.4 KiB
/* tnum: tracked (or tristate) numbers |
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* |
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* A tnum tracks knowledge about the bits of a value. Each bit can be either |
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* known (0 or 1), or unknown (x). Arithmetic operations on tnums will |
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* propagate the unknown bits such that the tnum result represents all the |
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* possible results for possible values of the operands. |
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*/ |
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#ifndef _LINUX_TNUM_H |
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#define _LINUX_TNUM_H |
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#include <linux/types.h> |
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struct tnum { |
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u64 value; |
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u64 mask; |
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}; |
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/* Constructors */ |
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/* Represent a known constant as a tnum. */ |
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struct tnum tnum_const(u64 value); |
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/* A completely unknown value */ |
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extern const struct tnum tnum_unknown; |
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/* A value that's unknown except that @min <= value <= @max */ |
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struct tnum tnum_range(u64 min, u64 max); |
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/* Arithmetic and logical ops */ |
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/* Shift a tnum left (by a fixed shift) */ |
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struct tnum tnum_lshift(struct tnum a, u8 shift); |
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/* Shift (rsh) a tnum right (by a fixed shift) */ |
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struct tnum tnum_rshift(struct tnum a, u8 shift); |
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/* Shift (arsh) a tnum right (by a fixed min_shift) */ |
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struct tnum tnum_arshift(struct tnum a, u8 min_shift, u8 insn_bitness); |
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/* Add two tnums, return @a + @b */ |
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struct tnum tnum_add(struct tnum a, struct tnum b); |
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/* Subtract two tnums, return @a - @b */ |
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struct tnum tnum_sub(struct tnum a, struct tnum b); |
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/* Bitwise-AND, return @a & @b */ |
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struct tnum tnum_and(struct tnum a, struct tnum b); |
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/* Bitwise-OR, return @a | @b */ |
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struct tnum tnum_or(struct tnum a, struct tnum b); |
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/* Bitwise-XOR, return @a ^ @b */ |
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struct tnum tnum_xor(struct tnum a, struct tnum b); |
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/* Multiply two tnums, return @a * @b */ |
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struct tnum tnum_mul(struct tnum a, struct tnum b); |
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/* Return a tnum representing numbers satisfying both @a and @b */ |
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struct tnum tnum_intersect(struct tnum a, struct tnum b); |
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/* Return @a with all but the lowest @size bytes cleared */ |
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struct tnum tnum_cast(struct tnum a, u8 size); |
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/* Returns true if @a is a known constant */ |
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static inline bool tnum_is_const(struct tnum a) |
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{ |
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return !a.mask; |
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} |
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/* Returns true if @a == tnum_const(@b) */ |
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static inline bool tnum_equals_const(struct tnum a, u64 b) |
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{ |
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return tnum_is_const(a) && a.value == b; |
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} |
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/* Returns true if @a is completely unknown */ |
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static inline bool tnum_is_unknown(struct tnum a) |
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{ |
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return !~a.mask; |
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} |
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/* Returns true if @a is known to be a multiple of @size. |
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* @size must be a power of two. |
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*/ |
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bool tnum_is_aligned(struct tnum a, u64 size); |
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/* Returns true if @b represents a subset of @a. */ |
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bool tnum_in(struct tnum a, struct tnum b); |
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/* Formatting functions. These have snprintf-like semantics: they will write |
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* up to @size bytes (including the terminating NUL byte), and return the number |
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* of bytes (excluding the terminating NUL) which would have been written had |
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* sufficient space been available. (Thus tnum_sbin always returns 64.) |
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*/ |
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/* Format a tnum as a pair of hex numbers (value; mask) */ |
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int tnum_strn(char *str, size_t size, struct tnum a); |
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/* Format a tnum as tristate binary expansion */ |
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int tnum_sbin(char *str, size_t size, struct tnum a); |
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/* Returns the 32-bit subreg */ |
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struct tnum tnum_subreg(struct tnum a); |
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/* Returns the tnum with the lower 32-bit subreg cleared */ |
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struct tnum tnum_clear_subreg(struct tnum a); |
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/* Returns the tnum with the lower 32-bit subreg set to value */ |
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struct tnum tnum_const_subreg(struct tnum a, u32 value); |
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/* Returns true if 32-bit subreg @a is a known constant*/ |
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static inline bool tnum_subreg_is_const(struct tnum a) |
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{ |
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return !(tnum_subreg(a)).mask; |
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} |
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#endif /* _LINUX_TNUM_H */
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