Trixter
Veteran Member
My 8088 is an NEC model, but is clearly not marked as an 80C88, assuming that one could be installed in the slot.
It is my understanding that all NEC 8088s use the later CMOS design.
My 8088 is an NEC model, but is clearly not marked as an 80C88, assuming that one could be installed in the slot.
It is my understanding that all NEC 8088s use the later CMOS design.
With its 8086 running at 9.54 MHz, my Tandy 1000RL scored block read 761 kb/s, block write 1006 kb/s, interleaved read 360 kb/s, and block write 362 kb/s. Setting the onboard 16-bit video to either 0 or 1 wait state(s) did not change these scores. As you'd expect from a member of the Tandy 1000 family, it system RAM for the video (it has 768K RAM installed: 640K for DOS and 128K for video).That is really fascinating stuff (the clones triggering an NMI for writing to the m6845, and the LCD having a 45Hz refresh)! I'm also surprised the hp palmtop had video memory nearly three times faster than CGA -- yet interleaving memory reads with CPU instructions is almost totally crippling... and a 90Hz (!!) refresh rate? That's insane. Really amazing what you can learn 25+ years after the fact.
Okay, the final version 0.4 of the CGA compatibility tester is here:
http://www.oldskool.org/pc/cgacomp
I updated the webpage to include a link to the reference video, as well as a streaming version. The video doesn't go over every single test, only the most demanding/incompatible ones, but it should be sufficient for those wondering what the "strikethrough" cursor, CGA snow, the horizontal retrace tests, etc. should look like.
I patched it to work on any speed machine, so you can run it on Pentiums if you so desire And it no longer requires a mathcoprocessor.
The buggy mouse support will be removed in a future version if I get around to it (it's not my GUI library and I don't want to troubleshoot mouse support if I don't have a mouse on the dev machine).
That is really fascinating stuff (the clones triggering an NMI for writing to the m6845, and the LCD having a 45Hz refresh)!
Ok. Interlached text mode works for me then.
NTalking of IBM character sets, the CGA/MDA got "Æ", "æ", "Å" and "å", however, "Ø" and "ø" is missing! How the @ did my IBM MDA card manage to produce that letter??? (Not that the letter is almost never used since I operate the computer in english, but it's kind of weird when I'm thinking of it. It got an IBM Character ROM, so it isn't re-fonted.)
Different countries got different character sets in ROM depending on their local language. When in doubt of what character set you're using, consult a standard U.S. character set table and see if it matches up.Talking of IBM character sets, the CGA/MDA got "Æ", "æ", "Å" and "å", however, "Ø" and "ø" is missing! How the @ did my IBM MDA card manage to produce that letter??? (Not that the letter is almost never used since I operate the computer in english, but it's kind of weird when I'm thinking of it. It got an IBM Character ROM, so it isn't re-fonted.)
The PC's Intel 8088 chip (1983 revision date) is incorrectly shown as an "80C88".
mov cx,2 ; test if following instruction will be
; repeated twice.
db 0F3h,26h,0ACh ; rep es: lodsb
jcxz Yes ; intel non-CMOS chips do not care of rep
jmp Nope ; before segment prefix override, NEC and
; CMOS-tech ones does.
Interlaced mode on the composite monitor is not any more readable than on the RGB monitor. Still, I'm amazed that pseudo-80x50 text is intelligible at all on a color composite monitor (glorified tunerless TV set) with 240 lines of resolution (manufacturer's spec).
As far as I can tell from some quick research, the 8088 did not switch to the fully static CMOS design except in the specifically designated 80C88 version, which also featured reduced power consumption and the ability to clock down to zero MHz for sleep mode. The standard 8088 used NMOS, while the faster 8088-2 and 8088-1 used HMOS and later HMOS-II ("N-channel depletion load silicon gate technology," as they explained it). HMOS-III was used for the 8086 series.If it's made after 1981, it actually is an 80c88, marked or not. They fixed the bug I test for when they went to the new manufacturing process.
As far as I can tell from some quick research, the 8088 did not switch to the fully static CMOS design except in the specifically designated 80C88 version, which also featured reduced power consumption and the ability to clock down to zero MHz for sleep mode. The standard 8088 used NMOS, while the faster 8088-2 and 8088-1 used HMOS and later HMOS-II ("N-channel depletion load silicon gate technology," as they explained it). HMOS-III was used for the 8086 series.
Were you able to find out what year they switched to the CMOS static design?
I've also got some feelers out for more info; if I find something definitive, I'll post here and/or change my detection routines
Maybe we could manually toggle the 8284A clock generator to see if it single-steps! The non-static version doesn't work quite well below 2 MHz.
yeah, unless your CPU got superpowers, but the problability for that is one to infinity (or zero) :D .I think that would be a tad difficult to do in software
Were you able to find out what year they switched to the CMOS static design?
I've also got some feelers out for more info; if I find something definitive, I'll post here and/or change my detection routines
mov cx,2 ; test if following instruction will be
; repeated twice.
db 0F3h,26h,0ACh ; rep es: lodsb
jcxz Yes ; intel non-CMOS chips do not care of rep
jmp Nope ; before segment prefix override, NEC and
; CMOS-tech ones does.
mov cx,f000 ; need a longer count to
; guarantee it will be interrupted
db 0F3h,26h,0ACh ; rep es: lodsb
jcxz Yes
jmp Nope