Full Adder
Comprehensive Analysis Report
Generated: Tue Jul 29 15:53:16 UTC 2025
Executive Summary
This report provides a comprehensive analysis of three full adder
implementations: - Carry Lookahead Implementation (5 gates, 32
transistors) - Simple XOR/AND Implementation (5 gates, 32 transistors) -
Half Adder Implementation (7 gates, 48 transistors)
Gate-Level Analysis
# Full Adder Gate-Level
Analysis Report
Gate Count Summary
| Carry Lookahead |
5 |
32 |
Flat |
| Simple XOR/AND |
5 |
32 |
Flat |
| Half Adder |
7 |
48 |
Hierarchical |
Carry Lookahead
Implementation
Gate Breakdown
| AND |
1 |
6 |
| ANDNOT |
1 |
4 |
| OR |
1 |
6 |
| XNOR |
2 |
16 |
Module Instances
| AND |
1 |
| XNOR |
2 |
| ANDNOT |
1 |
| OR |
1 |
Total Statistics
- Primitive Gates: 5
- Estimated Transistors: 32
- Design Style: Flat
Logic Complexity Analysis
- Carry Generation: Optimized carry lookahead
logic
- Sum Generation: XNOR-based sum calculation
- Advantage: Fast carry propagation
Simple XOR/AND Implementation
Gate Breakdown
| AND |
1 |
6 |
| ANDNOT |
1 |
4 |
| OR |
1 |
6 |
| XNOR |
2 |
16 |
Module Instances
| XNOR |
2 |
| AND |
1 |
| ANDNOT |
1 |
| OR |
1 |
Total Statistics
- Primitive Gates: 5
- Estimated Transistors: 32
- Design Style: Flat
Logic Complexity Analysis
- Carry Generation: Standard AND-OR logic
- Sum Generation: Cascaded XNOR gates
- Advantage: Simple and straightforward
Half Adder Implementation
Gate Breakdown
Module Instances
| OR |
1 |
| half_adder |
2 |
| XOR |
1 |
| AND |
1 |
Total Statistics
- Primitive Gates: 7
- Estimated Transistors: 48
- Design Style: Hierarchical
Logic Complexity Analysis
- Carry Generation: Two half-adder instances + OR
gate
- Sum Generation: Cascaded half-adder sum
outputs
- Advantage: Modular and reusable design
Area Efficiency
- Half Adder Implementation: Most modular, reusable
components
- Simple XOR/AND: Standard implementation, good
balance
- Carry Lookahead: Optimized for speed, similar
area
Design Trade-offs
- Area: All implementations use similar transistor
counts (~40-48)
- Speed: Carry lookahead optimized for fast carry
propagation
- Modularity: Half adder implementation most
modular
- Complexity: Simple XOR/AND easiest to
understand
Technology Considerations
Standard Cell Mapping
All implementations map to standard cell library: - AND, OR, XOR,
XNOR gates - AND-NOT gates for optimized logic - Compatible with most
CMOS processes
Power Considerations
- Static Power: Minimal (combinational logic)
- Dynamic Power: Proportional to switching
activity
- Clock Power: Only for clock/reset signals
(minimal)
Synthesis Statistics
=== Full Adder Synthesis Comparison Report === Generated: Tue Jul 29
15:53:16 UTC 2025
Carry Lookahead
Implementation
10. Printing statistics.
=== full_adder ===
Number of wires: 10
Number of wire bits: 10
Number of public wires: 7
Number of public wire bits: 7
Number of memories: 0
Number of memory bits: 0
Number of processes: 0
Number of cells: 5
$_ANDNOT_ 1
$_AND_ 1
$_OR_ 1
$_XNOR_ 2
Simple Implementation
10. Printing statistics.
=== full_adder_simple ===
Number of wires: 10
Number of wire bits: 10
Number of public wires: 7
Number of public wire bits: 7
Number of memories: 0
Number of memory bits: 0
Number of processes: 0
Number of cells: 5
$_ANDNOT_ 1
$_AND_ 1
$_OR_ 1
$_XNOR_ 2
Half Adder Implementation
10. Printing statistics.
=== full_adder_half_adder ===
Number of wires: 10
Number of wire bits: 10
Number of public wires: 10
Number of public wire bits: 10
Number of memories: 0
Number of memory bits: 0
Number of processes: 0
Number of cells: 3
$_OR_ 1
half_adder 2
=== half_adder ===
Number of wires: 4
Number of wire bits: 4
Number of public wires: 4
Number of public wire bits: 4
Number of memories: 0
Number of memory bits: 0
Number of processes: 0
Number of cells: 2
$_AND_ 1
$_XOR_ 1
=== design hierarchy ===
full_adder_half_adder 1
half_adder 2
Number of wires: 18
Number of wire bits: 18
Number of public wires: 18
Number of public wire bits: 18
Number of memories: 0
Number of memory bits: 0
Number of processes: 0
Number of cells: 5
$_AND_ 2
$_OR_ 1
$_XOR_ 2