3 ms·
Wait. What? The instruction pointer incremented as an LFSR and not a binary counter to save on transistors? That is the craziest thing I've heard. But also
by OhMeadhbh 3y ago
Wait. What? The instruction pointer incremented as an LFSR and not a binary counter to save on transistors? That is the craziest thing I've heard. But also kind of awesome. Digital designers of the ancient era were masters of the crazy-awesome.
- sifar 3y agoYes, the IP as a binary counter is a historical artifact :). If you look at the first computer reports, the IP was a binary counter because the memories were linear addressable since they were made from mercury tubes - so one could only increment by 1. This got carried over even though we developed RAM. One wonders what impact the LFSR would have on the processor cache architecture, since there is spatial locality is not preserved. There is also a potential to run the program in reverse.