07-24-2013, 02:47 PM
If the first half adder calculates the sum in 2 ticks, then it will be a 5.5 tick adder for the reasons that I described earlier (pistons take 1.5 ticks to retract).
07-24-2013, 02:47 PM
If the first half adder calculates the sum in 2 ticks, then it will be a 5.5 tick adder for the reasons that I described earlier (pistons take 1.5 ticks to retract).
07-24-2013, 03:39 PM
Proper has a one tick xor.
07-24-2013, 04:22 PM
I used Proper's '1 tick XOR' to make a 3 tick adder, but the XOR is actually very flawed. It requires a signal strength of at least 10 on both inputs, meaning that a repeater is necessary to extend the carry past 3 bits.
07-24-2013, 09:07 PM
Henke and I built a 2 tick (rising edge) adder on RDF a long time ago.
2*10*7. This is an old image but the design works with the fence gates replaced by pistons.
07-24-2013, 09:30 PM
(This post was last modified: 07-24-2013, 09:31 PM by CMOSprinkles.)
I guess that would be 2 ticks to output on the rising edge. I've seen this adder before, it relies on a '1 tick XNOR' that is actually 1.5 ticks (it relies on the state of 1 piston extending on the falling edge) making it 3 ticks on the falling edge. That is rather impressive still, but does this actually support instant-carry? I remember seeing a version of this adder on MinecraftForum, but it was a regular ripple carry adder.
When I finally get the chance to design my own CLE (once my laptop stops overheating, haha), I'll probably use this XNOR. It's 1.5 ticks in the worst case scenario, so that would make for a nice 4 tick CLE.
07-24-2013, 09:36 PM
It is instacarry of course. 2 ticks (again, rising edge) for 8 bits and +1 tick for every 8 bits. Henke came up with a great way of lengthening the carry line without having to put a gap between the adders every eight bits. I can post a picture if you want.
07-24-2013, 10:09 PM
Ahh, the old 2 tick adder paradigm. Tis my creation, I should test it for 1.5 worky-ness. (Proof of concept was huge, hilariously.)
07-24-2013, 10:24 PM
(This post was last modified: 07-24-2013, 10:26 PM by CMOSprinkles.)
Wow, now that I think about it, that would make the usual piston XOR 1.5 ticks instead of 2. However, that only makes Jxu's 4 tick instant carry adder into a 3.5 tick (5 on the falling edge) adder because it still takes 2 ticks to output carry from the first half adder. How does yours generate a carry in 1.5 ticks?
Oh, and how do you manage the instant carry? If it uses pistons to cut the carry, you have to add 1.5 ticks for that on the falling edge (1.5 ticks to XNOR result, 1.5 ticks to cut carry, and 1.5 ticks to second XNOR result would make it a 4.5 tick adder).
07-25-2013, 12:41 AM
Rising edge only*. The intention was to use it in heavy math units / have control lines (forced power) if used in any sequential environment.
07-25-2013, 07:02 AM
Oh. I guess it's still pretty close to a 4 tick adder, and I'm sure it would be much more compact than a 4 tick CLE using the same XNOR's. Although, 4.5 ticks just isn't the same as 4 ticks... Maybe you can use a 1.5 tick piston AND for the carry somehow, I really wish I could just hop on the server and start playing with that 1.5 tick XNOR... Damn you laptop, y u so hot.
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