08-23-2015, 09:44 AM
My theory is that a 3 ticks CCA is possible if we use some tricks.
The minimum ticks is 3 because there is at least 3 successive components:
1 - The first XOR, a NOR, a AND
2 - The comparator's carry
3 - The last XOR
As the comparator is 1 tick and it exist design for 1 tick XOR, steps 2 and 3 can take 1 ticks each. If we want 3 ticks, we have to make the first step 1 tick too.
There is 3 components:
- The XOR : We can make it 2 ticks because it can be done at the same time as the carry (the output of this XOR is linked to the input of the last XOR)
- The NOR : /(A+B) It's easy to make it 1 ticks
- The AND : /(/A+/B) It need 2 ticks to build an AND gate, that's the problem here.
A way to solve this is to give the illusion of a 3 ticks CCA in a CCA ALU by using the input inverter (either way, what the need of a CCA if it's not for an ALU?). As it can give both inverted and non inverted input within 1 tick, we can use it to take inverted inputs for the AND gate and make it a NOR witch is 1 tick.
So the CCA will have 4 inputs: A,B,/A,/B and the inverter will have 4 outputs. By mixing them, it's possible to have a system inverter+CCA witch is 4 ticks. As the inverter will be 1 ticks, it will be like the CCA is 3 ticks.
So in theory, it is possible to have a 3 ticks CCA inside a CCA ALU, but the design is hard to find as we had to fit 4 inputs inside a very compact space.
The minimum ticks is 3 because there is at least 3 successive components:
1 - The first XOR, a NOR, a AND
2 - The comparator's carry
3 - The last XOR
As the comparator is 1 tick and it exist design for 1 tick XOR, steps 2 and 3 can take 1 ticks each. If we want 3 ticks, we have to make the first step 1 tick too.
There is 3 components:
- The XOR : We can make it 2 ticks because it can be done at the same time as the carry (the output of this XOR is linked to the input of the last XOR)
- The NOR : /(A+B) It's easy to make it 1 ticks
- The AND : /(/A+/B) It need 2 ticks to build an AND gate, that's the problem here.
A way to solve this is to give the illusion of a 3 ticks CCA in a CCA ALU by using the input inverter (either way, what the need of a CCA if it's not for an ALU?). As it can give both inverted and non inverted input within 1 tick, we can use it to take inverted inputs for the AND gate and make it a NOR witch is 1 tick.
So the CCA will have 4 inputs: A,B,/A,/B and the inverter will have 4 outputs. By mixing them, it's possible to have a system inverter+CCA witch is 4 ticks. As the inverter will be 1 ticks, it will be like the CCA is 3 ticks.
So in theory, it is possible to have a 3 ticks CCA inside a CCA ALU, but the design is hard to find as we had to fit 4 inputs inside a very compact space.