21.5.2.4 Signed Division
When CTRLA.SIGNED is one, both the input and the result will be in 2’s complement format. The results of signed division are such that the remainder and dividend have the same sign and the quotient is negative if the dividend and divisor have opposite signs. 16-bit results are sign extended to 32-bits. Note that when the maximum negative number is divided by the minimum negative number, the resulting quotient overflows the signed integer range and will return the maximum negative number with no indication of the overflow. This occurs for 0x80000000 / 0xFFFFFFFF in 32-bit operation and 0x8000 / 0xFFFF in 16-bit operation.