BusNOT (Bus NOT)
Inputs
| Pin | Type | Description |
|---|---|---|
| A | bus8 | Input bus (8 bits) |
Outputs
| Pin | Type | Description |
|---|---|---|
| Q | bus8 | ~A (bitwise NOT) = 255 − A |
How It Works
Inverts each of the 8 bits independently. Each output bit is the logical NOT of the corresponding input bit.
Formula: Q = (~A) & 0xFF. In 8-bit arithmetic: Q = 255 − A. For example, if A = 0x55 (01010101), then Q = 0xAA (10101010).
Usage
Complement operations in ALU design. Combined with an adder, BusNOT enables subtraction via two's complement: A − B = A + (~B + 1). Apply BusNOT to B, then add 1 via the carry-in of an 8-bit adder.