| XC3000 | XC4000E | XC4000X | XC5200 | XC9000 | Spartan | SpartanXL | Virtex |
|---|---|---|---|---|---|---|---|
| N/A | N/A | N/A | N/A | N/A | N/A | N/A | Primitive |

MUXCY_L is used to implement a 1-bit high-speed carry propagate function. One such function can be implemented per logic cell (LC), for a total of 4-bits per configurable logic block (CLB). The direct input (DI) of an LC is connected to the DI input of the MUXCY_L. The carry in (CI) input of an LC is connected to the CI input of the MUXCY_L. The select input (S) of the MUX is driven by the output of the lookup table (LUT) and configured as an XOR function. The carry out (LO) of the MUXCY_L reflects the state of the selected input and implements the carry out function of each LC. When Low, S selects DI; when High, S selects CI.
The LO output can only connect to other inputs within the same CLB slice.
See also MUXCY and MUXCY_D.
| Inputs | Outputs | ||
|---|---|---|---|
| S | DI | CI | LO |
| 0 | 1 | X | 1 |
| 0 | 0 | X | 0 |
| 1 | X | 1 | 1 |
| 1 | X | 0 | 0 |