| XC3000 | XC4000E | XC4000X | XC5200 | XC9000 | Spartan | SpartanXL | Virtex |
|---|---|---|---|---|---|---|---|
| N/A | N/A | N/A | N/A | Macro | N/A | N/A | N/A |
When the ADD input is High, two 1-bit words (A0 and B0) are added with a carry-in (CI), producing a 1-bit output (S0) and a carry-out (CO). When the ADD input is Low, B0 is subtracted from A0, producing a result (S0) and borrow (CO). In add mode, CO represents a carry-out, and CO and CI are active-High. In subtract mode, CO represents a borrow, and CO and CI are active-Low.
| Inputs | Outputs | |||
|---|---|---|---|---|
| A0 | B0 | CI | S0 | CO |
| 0 | 0 | 0 | 0 | 0 |
| 0 | 1 | 0 | 1 | 0 |
| 1 | 0 | 0 | 1 | 0 |
| 1 | 1 | 0 | 0 | 1 |
| 0 | 0 | 1 | 1 | 0 |
| 0 | 1 | 1 | 0 | 1 |
| 1 | 0 | 1 | 0 | 1 |
| 1 | 1 | 1 | 1 | 1 |
Add Function, ADD=1
| Inputs | Outputs | |||
|---|---|---|---|---|
| A0 | B0 | CI | S0 | CO |
| 0 | 0 | 0 | 1 | 0 |
| 0 | 1 | 0 | 0 | 0 |
| 1 | 0 | 0 | 0 | 1 |
| 1 | 1 | 0 | 1 | 0 |
| 0 | 0 | 1 | 0 | 1 |
| 0 | 1 | 1 | 1 | 0 |
| 1 | 0 | 1 | 1 | 1 |
| 1 | 1 | 1 | 0 | 1 |
Subtract Function, ADD=0
Figure 3.15 ADSU1 Implementation XC9000 |  |
