3 ms·
> PA 8000 (1996): actually implemented as a 3-bit shift register with majority vote This actually seems interestingly different from the two-bit saturating cou
by Sniffnoy 9y ago
> PA 8000 (1996): actually implemented as a 3-bit shift register with majority vote
This actually seems interestingly different from the two-bit saturating counter. Like, it's not just a different way of implementing it; you can't realize the saturating counter as a "quotient" of the shift/vote scheme.
- oshepherd 9y agoIt's the same just with redundant representations (the 2-bit repr is the count of ones in the 3-bit repr) '00' -> '000' '01' -> '001', '010', '100' '10' -> '011', '101', '110' '11' -> '111' this kind of transformation is truly bread & butter in hardware; we regularly numbers between binary counts, mask/number-of-set-bits and one-hot representations for optimisation purposes.
- Sniffnoy 9y agoThat's the obvious attempt at an equivalence one would come up with on being told that they're the same, but, as I stated, it doesn't work. As an example: In the 2-bit saturating counter, if you start at 00, if you see a 1 and then a 0 you're back to where you started. Whereas in the bit-shift register, if you start at 000 and see a 1 and then a 0, you're now at 010, which would correspond to 01 rather than 00.