gwj / at91sam9263 · Commits

Commit 67fc07d3fba681f3362f7644a69b7a581a2670e8

Authored by ths
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
Inline Side-by-side
Showing 1 changed file with 4 additions and 2 deletions
host-utils.c
  View file @67fc07d
... ... @@ -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;
... ...