Commit 67fc07d3fba681f3362f7644a69b7a581a2670e8
1 parent
9278480e
Fix overflow when multiplying two large positive numbers.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3429 c046a42c-6fe2-441c-8c8c-71466251a162
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4 additions
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2 deletions
host-utils.c
... | ... | @@ -43,7 +43,8 @@ void muls64(int64_t *phigh, int64_t *plow, int64_t a, int64_t b) |
43 | 43 | ph = (a >> 32) * (b >> 32); |
44 | 44 | |
45 | 45 | ph += (int64_t)pm1 >> 32; |
46 | - pm1 = (uint64_t)((uint32_t)pm1) + pm2 + (pl >> 32); | |
46 | + ph += (int64_t)pm2 >> 32; | |
47 | + pm1 = (uint64_t)((uint32_t)pm1) + (uint64_t)((uint32_t)pm2) + (pl >> 32); | |
47 | 48 | |
48 | 49 | *phigh = ph + ((int64_t)pm1 >> 32); |
49 | 50 | *plow = (pm1 << 32) + (uint32_t)pl; |
... | ... | @@ -67,7 +68,8 @@ void mulu64(uint64_t *phigh, uint64_t *plow, uint64_t a, uint64_t b) |
67 | 68 | ph = (a >> 32) * (b >> 32); |
68 | 69 | |
69 | 70 | ph += pm1 >> 32; |
70 | - pm1 = (uint64_t)((uint32_t)pm1) + pm2 + (pl >> 32); | |
71 | + ph += pm2 >> 32; | |
72 | + pm1 = (uint64_t)((uint32_t)pm1) + (uint64_t)((uint32_t)pm2) + (pl >> 32); | |
71 | 73 | |
72 | 74 | *phigh = ph + (pm1 >> 32); |
73 | 75 | *plow = (pm1 << 32) + (uint32_t)pl; | ... | ... |