asm_ones32
sum32 = asm_ones32((const void *)ptr, n >> 2);
sum32 = asm_ones32(ptr, sizeof(ipov) / 4);
__uint32_t asm_ones32(const void *buf, int count); /* in 32 bit words */
sum = asm_ones32((const void *)ip, 5); /* 5x4 = 20 bytes */