Hi, When unrolling loops or do a mmx->sse2 conversion, loop counters need to be divided by half. E.g. func_c(int n) can accept any n, while func_mmx(int n) assumes n is even, and func_sse2(int n) requires n to be a multiple of 4. How to determine whether it's safe? -- Zuxy Beauty is truth, While truth is beauty. PGP KeyID: E8555ED6