HN

Comments (8)

• msephton
  My type of article! Thank you
• ataylor284_
  If anybody's interested in the V20 from a programming perspective, The User's Manual from NEC is here: https://archive.org/details/bitsavers_necV20V30U_11351331/mo....The V20 instruction set is interesting and has some very 1980s extensions. In addition to the 8080 emulation mode, it has instructions for binary-coded decimal arithmetic and bit fields.However, NEC uses their own naming scheme which makes picking out the differences from the 8088 unnecessarily difficult. The bits are the same but the mnemonics are different. For example, they renamed all the registers (AX -> AW, SI -> IX, etc) and many opcodes (JMP -> BR, REP MOVSB -> REP MOVBK).
• Menu

  klelatti
  Of course the V20’s microcode was the centre of an interesting legal dispute when NEC was sued by Intel.https://thechipletter.substack.com/p/intel-vs-nec-the-case-o...
• jeanmichelselli
  This is an amazing project, I'm always impressed by stuff like this. I'd be very curious to know, though, if there's a market for achievements like that.
• eigenform
  Lovely work, thanks for sharing!
• Menu

  ck2
  ha I remember that chip so wellinstant speed boost for IBM PCjust pop out the 8088 and put in a $20 V20only problems is some programs ran their clocks too fastwow that article is amazing, I cannot believe people can reverse engineer at that level, brilliant
• 486sx33
  [dead]