FLEX10K fast arithmetic path In an Altera FLEX10K FPGA, the dedicated carry chain provides a fast carry-forward function between which elements within the device fabric?

Introduction / Context:
Fast arithmetic in FPGAs relies on dedicated carry logic that bypasses general-purpose routing. In the FLEX10K architecture, this support is integrated so adders, counters, and accumulators can achieve high speed without excessive logic depth.

Given Data / Assumptions:

• FLEX10K organizes logic into Logic Elements (LEs) grouped into Logic Array Blocks (LABs).
• An LE contains a LUT-like combinational function and an optional flip-flop.
• The “carry chain” is a dedicated path that links arithmetic carry outputs to the next stage’s carry inputs.

Concept / Approach:
The carry chain runs between adjacent LEs to propagate carries efficiently. While LUTs are the combinational primitives, the architectural unit that owns the carry chain endpoint is the LE. EABs (embedded array blocks) are memory structures, and LABs are higher-level groupings; the carry path itself stitches LEs together.

Step-by-Step Solution:

Verification / Alternative check:
Device handbooks show carry-chain tap points at each LE, with chain segments stitched within a LAB and sometimes across to neighboring structures by specialized routing.

Why Other Options Are Wrong:
“LUTs” are part of an LE but the chain is defined at the LE level. “EABs” are block memories and not part of the carry chain. “LABs” are groups of LEs; the chain operates between the LEs contained within.

Common Pitfalls:
Equating LUT boundaries with carry-chain boundaries; in FLEX10K, the carry is architecturally documented between LEs, not generic LUT nodes or EABs.

Final Answer:
LEs