Fix overflow when multiplying two large positive numbers.

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3429 c046a42c-6fe2-441c-8c8c-71466251a162
This commit is contained in:
ths 2007-10-23 23:22:54 +00:00
parent 9278480e8f
commit 67fc07d3fb

View file

@ -43,7 +43,8 @@ void muls64(int64_t *phigh, int64_t *plow, int64_t a, int64_t b)
ph = (a >> 32) * (b >> 32);
ph += (int64_t)pm1 >> 32;
pm1 = (uint64_t)((uint32_t)pm1) + pm2 + (pl >> 32);
ph += (int64_t)pm2 >> 32;
pm1 = (uint64_t)((uint32_t)pm1) + (uint64_t)((uint32_t)pm2) + (pl >> 32);
*phigh = ph + ((int64_t)pm1 >> 32);
*plow = (pm1 << 32) + (uint32_t)pl;
@ -67,7 +68,8 @@ void mulu64(uint64_t *phigh, uint64_t *plow, uint64_t a, uint64_t b)
ph = (a >> 32) * (b >> 32);
ph += pm1 >> 32;
pm1 = (uint64_t)((uint32_t)pm1) + pm2 + (pl >> 32);
ph += pm2 >> 32;
pm1 = (uint64_t)((uint32_t)pm1) + (uint64_t)((uint32_t)pm2) + (pl >> 32);
*phigh = ph + (pm1 >> 32);
*plow = (pm1 << 32) + (uint32_t)pl;