jkg@pyr.gatech.EDU (Jim Greenlee) (10/04/87)
In article <189@megatek.UUCP> hollen@mana.UUCP (Dion Hollenbeck) writes: >Yes, indeed the V30 will execute 80186 code. It even has some instructions >which extend beyond the 80186 (f'r'instance - execute Z80 code). Well, I don't know about 80186 code, but it definitely does NOT execute Z80 code (not all of it, anyway). The V20/30 executes *8080* code, which is a subset of Z80 code (actually, it is proabably more appropriate to say that Z80 code is a superset of 8080 code). The Z80 was designed to be object-code compatible with the 8080, but with an enhanced instruction set. Zilog also redefined the instruction mnemonics. The V20/30 toggles into emulation mode by means of a software interrupt, so the 8080 instructions are more of an "instead of" than an "extension to" the 80x86 instruction set. In fact, there is a shareware program (V2080.COM) that does this, allowing some CP/M software to be executed directly on PC compatibles at full speed. >I have >a manual for the chip and would be glad to give a reference for how to >get one if any interest. Maybe you should read it :-). Actually, I heard a rumor about a year ago that NEC was working on a new chip in the V series that WOULD execute Z80 code directly - it was to be called the V25/35. No doubt it was delayed as a consequence of the lawsuit by Intel. No use dragging Zilog into the fray, right? :-) Can anybody { confirm | deny | embellish } this? Jim Greenlee -- The Shadow...!{allegra,amd,hplabs,ihnp4,seismo,ut-ngp}!gatech!gitpyr!jkg Jryy, abj lbh'ir tbar naq qbar vg! Whfg unq gb xrrc svqqyvat jvgu vg hagvy lbh oebxr vg, qvqa'g lbh?!
gkb@necntc.NEC.COM (Greg Busby) (10/05/87)
In article <4157@pyr.gatech.EDU> jkg@pyr.UUCP (Jim Greenlee) writes: >In article <189@megatek.UUCP> hollen@mana.UUCP (Dion Hollenbeck) writes: >>Yes, indeed the V30 will execute 80186 code. It even has some instructions >>which extend beyond the 80186 (f'r'instance - execute Z80 code). > >Well, I don't know about 80186 code, but it definitely does NOT execute >Z80 code (not all of it, anyway). The V20/30 executes *8080* code, which >is a subset of Z80 code (actually, it is proabably more appropriate to >say that Z80 code is a superset of 8080 code). >The V20/30 toggles into emulation mode by means of a software interrupt, >so the 8080 instructions are more of an "instead of" than an "extension to" >the 80x86 instruction set. In fact, there is a shareware program (V2080.COM) >that does this, allowing some CP/M software to be executed directly on PC >compatibles at full speed. > >Actually, I heard a rumor about a year ago >that NEC was working on a new chip in the V series that WOULD execute Z80 >code directly - it was to be called the V25/35. No doubt it was delayed >as a consequence of the lawsuit by Intel. No use dragging Zilog into the >fray, right? :-) Can anybody { confirm | deny | embellish } this? > > Jim Greenlee Jim is right in his first paragraph -- the V20/30 has an emulation mode which allows it to execute 8080 instructions directly. It can, however, directly call 8086 subroutines from within the emulation mode, so it can sort of act as an "extension to" the 8086 instruction set (the 8086 subroutine is really a vectored interrupt, but that's just how it's done). There was a rumor about a year ago of a full Z80 instruction set, and it was true then. It wasn't the V25/35 though, but more on that later. The chip was going to set up a software emulator somehow and execute the additional Z80 instructions. This was tabled in the US though, although they may still be doing it in Japan (you'd have to contact NEC Japan for further info on that). The V25/35 is single-chip micro-_computer_, not a microprocessor. It has lots of neat things like on-chip A/D, timers, counters, serial I/O, RAM, ROM, and probably some other things since I don't have the product description right here. It runs 80188/86 code just like the V20/30, but also has some special instructions to access the on-chip goodies. It's big applications are in real-time control systems, and it has the advantage that a lot of the tools PC users are used to produce code that it can use. Disclaimer: I work for NEC Electronics supporting development tools for the V-Series among other microprocessors, they pay my salary and provide this machine. (Unabashed horn-blowing:) They do make good products. GKB