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8088 support?

Open globalcitizen opened this issue 8 years ago • 3 comments

Not sure but curious since these chips were apparently quite similar: does this also support the 8088?

I just uploaded some spiffing snaps of a modern machine yesterday (feel free to use)...

  • front
  • rear
  • inside view one
  • inside view two

... the machine in question was donated to the Australian Computer Museum Society.

globalcitizen avatar Jan 01 '17 20:01 globalcitizen

I don't think there are software visible differences between 8086 and 8088 (except perhaps bus access timing differences.)

minux avatar Jan 01 '17 20:01 minux

There are differences between 8086 and 8088 visible to self-modifying code due to the different size of the prefetch queue (IIRC, 6 bytes on 8086 but 4 on 8088). This does not depend on bus or memory timing, and is AFAIK the only reliable way for a program to distinguish 8086 from 8088. Most simulators don't bother simulating the prefetch queue at all, let alone accurately, in which case code attempting to determine the prefetch queue length will fail.

brouhaha avatar Jun 08 '20 01:06 brouhaha

On Sun, Jun 7, 2020 at 9:33 PM Eric Smith [email protected] wrote:

There are differences between 8086 and 8088 visible to self-modifying code due to the different size of the prefetch queue (IIRC, 6 bytes on 8086 but 4 on 8088). This does not depend on bus or memory timing, and is AFAIK the only reliable way for a program to distinguish 8086 from 8088. Most simulators don't bother simulating the prefetch queue at all, let alone accurately, in which case code attempting to determine the prefetch queue length will fail.

For 8086tiny, there is no prefetch queue at all, so prefetch queue length detection via SMC will fail anyway. Therefore, I think 8088 support is already as good as it could be by 8086tiny.

minux avatar Jun 08 '20 02:06 minux