b7cd3db6f4
The memory API supports 64-bit buses (e.g. PCI). A size on such a bus cannot be represented with a 64-bit data type, if both 0 and the entire address space size are to be represented. Futhermore, any address arithemetic may overflow and return unexpected results. Introduce a 128-bit signed integer type for use in such cases. Addition, subtraction, and comparison are the only operations supported. Signed-off-by: Avi Kivity <avi@redhat.com>
117 lines
1.9 KiB
C
117 lines
1.9 KiB
C
#ifndef INT128_H
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#define INT128_H
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typedef struct Int128 Int128;
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struct Int128 {
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uint64_t lo;
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int64_t hi;
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};
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static inline Int128 int128_make64(uint64_t a)
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{
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return (Int128) { a, 0 };
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}
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static inline uint64_t int128_get64(Int128 a)
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{
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assert(!a.hi);
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return a.lo;
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}
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static inline Int128 int128_zero(void)
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{
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return int128_make64(0);
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}
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static inline Int128 int128_one(void)
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{
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return int128_make64(1);
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}
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static inline Int128 int128_2_64(void)
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{
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return (Int128) { 0, 1 };
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}
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static inline Int128 int128_add(Int128 a, Int128 b)
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{
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Int128 r = { a.lo + b.lo, a.hi + b.hi };
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r.hi += (r.lo < a.lo) || (r.lo < b.lo);
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return r;
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}
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static inline Int128 int128_neg(Int128 a)
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{
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a.lo = ~a.lo;
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a.hi = ~a.hi;
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return int128_add(a, int128_one());
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}
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static inline Int128 int128_sub(Int128 a, Int128 b)
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{
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return int128_add(a, int128_neg(b));
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}
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static inline bool int128_nonneg(Int128 a)
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{
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return a.hi >= 0;
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}
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static inline bool int128_eq(Int128 a, Int128 b)
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{
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return a.lo == b.lo && a.hi == b.hi;
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}
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static inline bool int128_ne(Int128 a, Int128 b)
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{
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return !int128_eq(a, b);
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}
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static inline bool int128_ge(Int128 a, Int128 b)
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{
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return int128_nonneg(int128_sub(a, b));
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}
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static inline bool int128_lt(Int128 a, Int128 b)
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{
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return !int128_ge(a, b);
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}
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static inline bool int128_le(Int128 a, Int128 b)
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{
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return int128_ge(b, a);
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}
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static inline bool int128_gt(Int128 a, Int128 b)
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{
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return !int128_le(a, b);
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}
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static inline bool int128_nz(Int128 a)
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{
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return a.lo || a.hi;
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}
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static inline Int128 int128_min(Int128 a, Int128 b)
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{
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return int128_le(a, b) ? a : b;
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}
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static inline Int128 int128_max(Int128 a, Int128 b)
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{
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return int128_ge(a, b) ? a : b;
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}
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static inline void int128_addto(Int128 *a, Int128 b)
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{
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*a = int128_add(*a, b);
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}
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static inline void int128_subfrom(Int128 *a, Int128 b)
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{
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*a = int128_sub(*a, b);
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}
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#endif
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