Normal Mode; Extended Lut Mode; Arithmetic Mode - Altera Cyclone V Device Handbook

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Normal Mode

Normal mode allows two functions to be implemented in one Cyclone V ALM, or a single function of up

to six inputs.

Up to eight data inputs from the LAB local interconnect are inputs to the combinational logic.

The ALM can support certain combinations of completely independent functions and various combinations

of functions that have common inputs.

In this mode, if the 7-input function is unregistered, the unused eighth input is available for register packing.

Functions that fit into the template, as shown in the following figure, often appear in designs as "if-else"

statements in Verilog HDL or VHDL code.

Figure 1-7: Template for Supported 7-Input Functions in Extended LUT Mode for Cyclone V Devices

The ALM in arithmetic mode uses two sets of two 4-input LUTs along with two dedicated full adders.

The dedicated adders allow the LUTs to perform pre-adder logic; therefore, each adder can add the output

of two 4-input functions.

The ALM supports simultaneous use of the adder's carry output along with combinational logic outputs.

The adder output is ignored in this operation.

Using the adder with the combinational logic output provides resource savings of up to 50% for functions

that can use this mode.

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This input is available

for register packing.

Logic Array Blocks and Adaptive Logic Modules in Cyclone V Devices

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