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avoid undefined shifts with multi-word bitmaps

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Daniel Micay 2018-10-14 18:57:59 -04:00
parent 7798b2693e
commit 535466fdfd
1 changed files with 6 additions and 3 deletions
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9
malloc.c
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@ -199,15 +199,18 @@ static struct slab_metadata *alloc_metadata(struct size_class *c, size_t slab_si
} }
static void set_slot(struct slab_metadata *metadata, size_t index) { static void set_slot(struct slab_metadata *metadata, size_t index) {
metadata->bitmap[index / 64] |= 1UL << index; size_t bucket = index / 64;
metadata->bitmap[bucket] |= 1UL << (index - bucket * 64);
} }
static void clear_slot(struct slab_metadata *metadata, size_t index) { static void clear_slot(struct slab_metadata *metadata, size_t index) {
metadata->bitmap[index / 64] &= ~(1UL << index); size_t bucket = index / 64;
metadata->bitmap[bucket] &= ~(1UL << (index - bucket * 64));
} }
static bool get_slot(struct slab_metadata *metadata, size_t index) { static bool get_slot(struct slab_metadata *metadata, size_t index) {
return (metadata->bitmap[index / 64] >> index) & 1UL; size_t bucket = index / 64;
return (metadata->bitmap[bucket] >> (index - bucket * 64)) & 1UL;
} }
static u64 get_mask(size_t slots) { static u64 get_mask(size_t slots) {