Comment by userbinator

16 hours ago

I agree with the first comment there, that it's important to know which revision of the 386 this came from, since the 386 did receive many small changes over its 22-year production run.

2 comments

userbinator

rep_lodsb 10 hours ago

Well, one indication is the value loaded into EDX on reset:

    9B5 BIST1  -> TMPD    0x0303         PASS2
    9B6 SIGMA  -> EDX
    9B7 BIST2  -> TMPE    TMPD           XOR
    9B8 SIGMA             0x3ddc0c2c     XOR
    9B9 SIGMA  -> EAX     BOOTUP_JUMP    JFPUOK

0x303 = family 3, model 0, stepping id 3.

userbinator 9 hours ago

That's either a B0 or B1 according to https://www.pcjs.org/documents/manuals/intel/80386/ , or an A3 according to https://www.geoffchappell.com/studies/windows/km/cpu/precpui... , all of which are very buggy.