A common FP4 layout is 1 sign bit, 3 exponent bits, 0 mantissa bits. There's just not that much difference in complexity between that and a 4-bit integer---the

A common FP4 layout is 1 sign bit, 3 exponent bits, 0 mantissa bits. There's just not that much difference in complexity between that and a 4-bit integer---the ALU can just be a simple table lookup, for both FP and integer.