4 ms·
Yes, I've been working through different parts of the 8086 lately. My goal is to understand the microcode. I hope people aren't getting tired of the 8086 :-)
by kens 6y ago
Yes, I've been working through different parts of the 8086 lately. My goal is to understand the microcode. I hope people aren't getting tired of the 8086 :-)
- tyingq 6y agoMaybe the NEC V33 would be interesting to compare. 8086 compatible, but all done with regular logic, no microcode.
- justin66 6y agoThat's pretty interesting. How does the transistor count compare?
- kens 6y agoI'm surprised that NEC would do away with the microcode, since there is a lot of microcode in the 8086. It would be interesting to see how much circuitry it took to replace the microcode.
- tyingq 6y agoSupposedly that made it twice as fast at the same clock speed.
- tpmx 6y agoSomeone (not me!) edited https://en.wikipedia.org/wiki/NEC_V20 https://en.wikipedia.org/wiki/NEC_V20 to say "The NEC V33 is a super version of the V30 that separates address bus and data bus, and executes all instructions with wired logic instead of micro-codes, making it twice as fast as a V30 for the same clock frequency. V33 has the performance equivalent to Intel 80286. NEC V33 offers a method to expanding the memory address space to 16M bytes. It has two additional instructions BRKXA and RETXA to support extended addressing mode. The 8080 emulation mode was not supported."
- Arcorann 6y agoAccording to the Japanese Wikipedia page [1] it was actually in response to a lawsuit about V30 breaching the copyright of 8086 microcode. The extra speed would just be a bonus. [1] https://ja.wikipedia.org/wiki/NEC_Vシリーズ https://ja.wikipedia.org/wiki/NEC_Vシリーズ
- ckastner 6y ago> I hope people aren't getting tired of the 8086 :-) On the contrary! These posts are fascinating and captivating!
- bogomipz 6y agoNo, quite the opposite. I look forward to reading your news posts. And this is generally how I find out about them. Please keep up the great work.