static int satsub64be(const unsigned char *v1,const unsigned char *v2)
{	int ret,sat,brw,i;

	if (sizeof(long) == 8) do
	{	const union { long one; char little; } is_endian = {1};
		long l;

		if (is_endian.little)			break;
		/* not reached on little-endians */
		/* following test is redundant, because input is
		 * always aligned, but I take no chances... */
		if (((size_t)v1|(size_t)v2)&0x7)	break;

		l  = *((long *)v1);
		l -= *((long *)v2);
		if (l>128)		return 128;
		else if (l<-128)	return -128;
		else			return (int)l;
	} while (0);

	ret = (int)v1[7]-(int)v2[7];
	sat = 0;
	brw = ret>>8;	/* brw is either 0 or -1 */
	if (ret & 0x80)
	{	for (i=6;i>=0;i--)
		{	brw += (int)v1[i]-(int)v2[i];
			sat |= ~brw;
			brw >>= 8;
		}
	}
	else
	{	for (i=6;i>=0;i--)
		{	brw += (int)v1[i]-(int)v2[i];
			sat |= brw;
			brw >>= 8;
		}
	}
	brw <<= 8;	/* brw is either 0 or -256 */

	if (sat&0xff)	return brw | 0x80;
	else		return brw + (ret&0xFF);
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.