Yes, the prefetch queue is implemented the same as the real 8088. The music playing at the end of the 8088 MPH demo relies on the prefetch queue operating correctly and the PCXT core seems to run this fine. Also the tools which identify the processor type using the prefetch queue correctly identify the core as an 8088.
Search found 96 matches
- Fri Jun 02, 2023 4:45 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Instruction prefetch cache?
- Replies: 1
- Views: 2744
- Tue Jan 17, 2023 8:35 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Ideas for PCAT
- Replies: 36
- Views: 12602
Re: Ideas for PCAT
- Sat Jan 14, 2023 3:27 am
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Ideas for PCAT
- Replies: 36
- Views: 12602
Re: Ideas for PCAT
Also from reading wikipedia, it mentions that 386 embedded chips did not have real mode at all.
Could you please share where you found this?
- Sat Jan 14, 2023 1:08 am
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Ideas for PCAT
- Replies: 36
- Views: 12602
Re: Ideas for PCAT
Would a 80386 that only operates in real mode be interesting? Implementing protected mode is a heavy lift and DOS doesnt even use it...
Speaking of which, was the 386 widely used as an embedded processor? If so, was it used in real mode or was there a need for protected mode in embedded applications?
- Mon Dec 12, 2022 4:34 am
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Ideas for PCAT
- Replies: 36
- Views: 12602
Re: Ideas for PCAT
If you only want a speed boost then it can be achieved most easily by making improvements to the PCXT core - I have posted notes in this forum on how it can be done. If there is no interest in this level of effort then developing a new 80286 core and chipset are even more unlikely...
- Sun Dec 04, 2022 5:27 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: MCL86 featured on hackaday
- Replies: 2
- Views: 908
Re: MCL86 featured on hackaday
The MCL86 has become more visible because of the MiSTer PCXT core which I have all of you to thank for!
- Wed Nov 30, 2022 6:35 am
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Tandy 1000 TX?
- Replies: 12
- Views: 2001
Re: Tandy 1000 TX?
- Mon Nov 28, 2022 6:38 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Some 8088 instruction bugs
- Replies: 3
- Views: 1253
Re: Some 8088 instruction bugs
- Fri Nov 18, 2022 4:33 am
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Interesting Tests We Could Run For x86
- Replies: 25
- Views: 2954
Re: Interesting Tests We Could Run For x86
- Wed Nov 16, 2022 6:25 am
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: PCXT Core 10Mhz CPU Speed Possible?
- Replies: 101
- Views: 8336
Re: PCXT Core 10Mhz CPU Speed Possible?
https://www.youtube.com/watch?v=d_aj3bG45agI can already hear the monotonous Pengo song in my head.
Pengo isnt much fun when the 8088 is not cycle accurate.
- Wed Nov 16, 2022 3:49 am
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: PCXT Core 10Mhz CPU Speed Possible?
- Replies: 101
- Views: 8336
Re: PCXT Core 10Mhz CPU Speed Possible?
spark2k06 wrote: ↑Tue Nov 15, 2022 2:35 pmkitune-san wrote: ↑Tue Nov 15, 2022 2:31 pm hmm.. I don't know what to say.
I have not found any bottlenecks yet.
However, I would not say that there is not something that is a bottleneck.Let's see what @MicroCoreLabs has to sayMicroCoreLabs wrote:
You tell me. You just ran speed tests and asked me what the bottlenecks were...But having ao486 already, useful for exactly what
- Wed Nov 16, 2022 3:43 am
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: PCXT Core 10Mhz CPU Speed Possible?
- Replies: 101
- Views: 8336
Re: PCXT Core 10Mhz CPU Speed Possible?
Virtually nothing uses the 8087... Maximum speed will always be useful.for example, how about having an 8087?
- Wed Nov 16, 2022 3:41 am
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: PCXT Core 10Mhz CPU Speed Possible?
- Replies: 101
- Views: 8336
Re: PCXT Core 10Mhz CPU Speed Possible?
- Wed Nov 16, 2022 3:10 am
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: PCXT Core 10Mhz CPU Speed Possible?
- Replies: 101
- Views: 8336
Re: PCXT Core 10Mhz CPU Speed Possible?
- Tue Nov 15, 2022 6:30 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: PCXT Core 10Mhz CPU Speed Possible?
- Replies: 101
- Views: 8336
Re: PCXT Core 10Mhz CPU Speed Possible?
- Sun Nov 13, 2022 7:13 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: PCXT Core 10Mhz CPU Speed Possible?
- Replies: 101
- Views: 8336
Re: PCXT Core 10Mhz CPU Speed Possible?
- Sun Nov 13, 2022 5:20 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: PCXT Core 10Mhz CPU Speed Possible?
- Replies: 101
- Views: 8336
Re: PCXT Core 10Mhz CPU Speed Possible?
Did I say that?Even less than 25MHz could be the maximum limit imposed by the MCL86 architecture, if I'm not mistaken... I think @MicroCoreLabs said something about that.
I covered this in a previous post, but you can achieve the greatest acceleration by changing the BIU to complete DRAM accesses outside of the local bus state machine.
- Mon Nov 07, 2022 9:49 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: IBM PCjr BIOS in PCXT Core
- Replies: 27
- Views: 3800
- Sun Oct 30, 2022 10:08 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: IBM PCjr BIOS in PCXT Core
- Replies: 27
- Views: 3800
Re: IBM PCjr BIOS in PCXT Core
- Sun Oct 30, 2022 9:00 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: FDD Support Based on ao486 Implementation
- Replies: 93
- Views: 23119
Re: FDD Support Based on ao486 Implementation
- Sun Oct 30, 2022 6:26 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: FDD Support Based on ao486 Implementation
- Replies: 93
- Views: 23119
Re: FDD Support Based on ao486 Implementation
- Sat Oct 29, 2022 6:10 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Some Research Over the Keyboard Issues on Hang Shift for Keyb sp
- Replies: 16
- Views: 1677
Re: Some Research Over the Keyboard Issues on Hang Shift for Keyb sp
- Sat Oct 29, 2022 5:22 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Some Research Over the Keyboard Issues on Hang Shift for Keyb sp
- Replies: 16
- Views: 1677
Re: Some Research Over the Keyboard Issues on Hang Shift for Keyb sp
- Sun Sep 25, 2022 6:44 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: 8088 CPU
- Replies: 8
- Views: 1761
Re: 8088 CPU
Yes it does increment. Please see my BIU code on GitHub. Also remember that the address will wrap over the segment.When a word access is executed to an I/O device (out, in), is the address incremented on the second access?
For example a word read at 0xAFFFF will read from 0xAFFFF and then 0xA0000. It will not read from 0xAFFFF and 0xB0000.
- Sun Sep 25, 2022 1:08 am
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: 8088 CPU
- Replies: 8
- Views: 1761
Re: 8088 CPU
This was my full statement.It would be very hard to emulate this behavior exactly so I just picked a number in the middle of the range which yielded good results.
Practically anything can be done in a software emulator so there is no surprise that cycle-exact emulators exist. Doing so in microcode running in an FPGA is a different story...
- Sat Sep 24, 2022 6:20 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: 8088 CPU
- Replies: 8
- Views: 1761
Re: 8088 CPU
- Fri Sep 23, 2022 9:29 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Interesting Tests We Could Run For x86
- Replies: 25
- Views: 2954
Re: Interesting Tests We Could Run For x86
- Fri Sep 23, 2022 4:11 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Interesting Tests We Could Run For x86
- Replies: 25
- Views: 2954
Re: Interesting Tests We Could Run For x86
- Thu Sep 22, 2022 8:43 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Interesting Tests We Could Run For x86
- Replies: 25
- Views: 2954
Re: Interesting Tests We Could Run For x86
- Sun Sep 18, 2022 8:47 pm
- Forum: IBM PC, PCXT, Tandy 1000
- Topic: Saving BRAM To Facilitate Ports and New Developments
- Replies: 25
- Views: 3104