Refinement of Generate ($G$) and Propagate ($P$) Signals
In the initial architecture, the logic generation for the 74182 look-ahead unit was bottlenecked by a naïve implementation using AND and XOR gates. This approach was inherently bloated, requiring a massive array of 74541 inverting drivers to handle the logic inversion, which created unnecessary routing congestion and footprint bloat.
I have overhauled this logic layer to prioritize efficiency and routing symmetry:
Logical Optimization: By swapping the AND gates for NAND gates, I have eliminated the need for the redundant 74541 inverter bank.
Inverter Consolidation: To maintain a clean signal path, I am now utilizing the spare gates within existing NAND packages as single-input inverters (via the identity $\text{NAND}(a, a) = \neg a$). This approach bypasses the complexity of XNOR configurations, which would have introduced open-drain headaches and required tedious pull-up resistor management.
Result: This optimization is a net gain for board "Fractal Competence," reducing the footprint requirement by approximately 8 inverting driver chips and simplifying the trace density significantly.
74283 Integration
The core arithmetic logic has been transitioned to a 74283-based implementation. The 32-bit ALU is now modularized into eight discrete 4-bit slices, with each slice paired to a dedicated 74283 chip. This allows for a clean, repetitive layout in KiCad that mirrors the natural 4-bit flow of the logic, facilitating shorter signal paths and improved timing stability for higher theoretical MHz target.
The routing is now strictly localized to these slices, aligning perfectly with the intended hardware-software co-design goals.