4 ms·

And what about 8088? Because it become more popular due 8 bit I/O data channel.

kens 6y ago
I've ordered an 8088 so I can compare the internal circuitry of the chips. They should be mostly the same, except that the 8088 has an 8-bit data bus externally and has 4 bytes of prefetch buffer instead of 6.
- mobilio 6y ago
  Yes, i know. Will wait for this article!
- Taniwha 6y ago
  remember that the address and data pins are multiplexed - the 8088 and 8086 have the same number of pins My guess is that the prefetch buffer is always 6 bytes but the 8088 fetches instructions more slowly and never fills it past 4 instructions I think they're probably the same die, the thing to look for is whether there's a bonding difference
  - robocat 6y ago
    > I think they're probably the same die Very unlikely. The 8088 was developed after the 8086, and there are more pin differences including m/io inverting to io/m.
    - mrlonglong 6y ago
      Now I really want to get a 8086 on a bread board and see if I can do things with it! What else do I need to put on the breadboard to build a minimum computer?
      - mlaux 6y ago
        Probably just a voltage regulator, a clock source, reset pin logic, a couple ROM chips (2 8-bit wide chips or 1 16-bit wide), some static RAM, a PAL/GAL/74xx logic for address decoding and chip select pins, stuff to deal with the multiplexing, and whatever input/output you want (bus buffers for parallel I/O, off the shelf UART chips, etc) I’ve only done it with the 6502 and Z80, but the 8086 shouldn’t be too much harder. There are plenty of resources available online for those two chips that you could adapt!
      - rasz 6y ago
        http://www.malinov.com/Home/sergeys-projects/xi-8088 http://www.malinov.com/Home/sergeys-projects/xi-8088 http://tech.mattmillman.com/projects/8od/ http://tech.mattmillman.com/projects/8od/ http://www.s100computers.com/My http://www.s100computers.com/My System Pages/8086 Board/8086 CPU Board.htm
      - kevin_thibedeau 6y ago
        In minimum mode you don't need more than a ROM, SRAM, and clock source.
- kiwidrew 6y ago
  That's fantastic news! I'm interested to see whether the 8086 and 8088 use the same microcode or whether the only difference between the chips is in the BIU itself. I've always wanted a "visual 6502" style emulation of the original IBM PC, and a high-resolution die photo is the first step. Cycle-accurate emulation of the 8088 is fiendishly difficult thanks to the complex interactions between the EU and BIU.
alex_young 6y ago
The 8088 was an 8086 with half the bus. https://en.wikipedia.org/wiki/Intel_8088 https://en.wikipedia.org/wiki/Intel_8088

kens 6y ago

I've ordered an 8088 so I can compare the internal circuitry of the chips. They should be mostly the same, except that the 8088 has an 8-bit data bus externally and has 4 bytes of prefetch buffer instead of 6.

mobilio 6y ago
Yes, i know. Will wait for this article!
Taniwha 6y ago
remember that the address and data pins are multiplexed - the 8088 and 8086 have the same number of pins My guess is that the prefetch buffer is always 6 bytes but the 8088 fetches instructions more slowly and never fills it past 4 instructions I think they're probably the same die, the thing to look for is whether there's a bonding difference
- robocat 6y ago
  > I think they're probably the same die Very unlikely. The 8088 was developed after the 8086, and there are more pin differences including m/io inverting to io/m.
  - mrlonglong 6y ago
    Now I really want to get a 8086 on a bread board and see if I can do things with it! What else do I need to put on the breadboard to build a minimum computer?
    - mlaux 6y ago
      Probably just a voltage regulator, a clock source, reset pin logic, a couple ROM chips (2 8-bit wide chips or 1 16-bit wide), some static RAM, a PAL/GAL/74xx logic for address decoding and chip select pins, stuff to deal with the multiplexing, and whatever input/output you want (bus buffers for parallel I/O, off the shelf UART chips, etc) I’ve only done it with the 6502 and Z80, but the 8086 shouldn’t be too much harder. There are plenty of resources available online for those two chips that you could adapt!
    - rasz 6y ago
      http://www.malinov.com/Home/sergeys-projects/xi-8088 http://www.malinov.com/Home/sergeys-projects/xi-8088 http://tech.mattmillman.com/projects/8od/ http://tech.mattmillman.com/projects/8od/ http://www.s100computers.com/My http://www.s100computers.com/My System Pages/8086 Board/8086 CPU Board.htm
    - kevin_thibedeau 6y ago
      In minimum mode you don't need more than a ROM, SRAM, and clock source.
kiwidrew 6y ago
That's fantastic news! I'm interested to see whether the 8086 and 8088 use the same microcode or whether the only difference between the chips is in the BIU itself. I've always wanted a "visual 6502" style emulation of the original IBM PC, and a high-resolution die photo is the first step. Cycle-accurate emulation of the 8088 is fiendishly difficult thanks to the complex interactions between the EU and BIU.

alex_young 6y ago

The 8088 was an 8086 with half the bus. https://en.wikipedia.org/wiki/Intel_8088 https://en.wikipedia.org/wiki/Intel_8088