8-bit Carry Cancel Adder
- 5 ticks
- 936
- 18×4×13
Verified specs
Credits
File
- Name
8_bit_Carry_Cancel_Adder.schem- Uploaded
- November 1, 2026
- Last edited
- November 1, 2026
- Downloads
- 0
- Conventions
- followed
Inputs and outputs
| Input | Bits | Power | Delay |
|---|---|---|---|
| A | 8 | hard | t = 0 |
| B | 8 | hard | −1t |
| carry in | 1 | soft | 0t |
| Output | Bits | First change | Settles |
| 8 | 4t | 5t | |
| bit 0 | 4t | 5t | |
| bit 1 | 4t | 5t | |
| bit 2 | 4t | 5t | |
| bit 3 | 4t | 5t | |
| bit 4 | 4t | 5t | |
| bit 5 | 4t | 5t | |
| bit 6 | 4t | 5t | |
| bit 7 | 4t | 5t | |
| carry out | 1 | 4t | 5t |
Block distribution
- Solid
- 344
- Dust
- 205
- Transparent
- 46
- Comparator
- 42
- Repeater
- 41
- Torch
- 19
- Lever
- 17
Description
The first 4-wide CCA. 
mop_u realized he could use XNOR instead of AND for generate, because the unwanted bit of XNOR is cancelled by NOR in the kill.
Timing
- Synced
- ✗
- Bits apart, output
- 172,952 changes
- Changes tested
- 915,456
output, bit by bit
| Bit | First changes | Settles by | Glitches |
|---|---|---|---|
| 0 | 4 | 5 | 16,384 |
| 1 | 4 | 5 | 4,096 |
| 2 | 4 | 5 | 1,024 |
| 3 | 4 | 5 | 256 |
| 4 | 4 | 5 | 64 |
| 5 | 4 | 5 | 16 |
| 6 | 4 | 5 | 4 |
| 7 | 4 | 5 | 1 |
Versions
| Version | Date | By | What it fixed | File |
|---|---|---|---|---|
| 2, current | 2026-11-01 | Unused blocks taken out | ||
| 1 | 2026-11-01 | embizone | First upload | Download |