Support i486

[dd86k]

Someone actually ran ddcpuid on an 80486DX2, and since OMF is still supported (for now), I think it may be worthwhile to:

• Test for FPU (FNINIT, Check SW).
• Test EFLAGS[ID] bit (CPUID instruction).

Low priority because OMF support is about to be kicked out sooner or later, and I have a project in the works to cover processors from 8086 to Pentium III.

[dd86k]

Could do 0.21.1 with i486 support.

So "CPU ID" can mean three things in x86:

• Quirks within processor: 8086-i486 (currently working on a new project to cover these)
• Identification number in DX register after reset: 80386-i486 (didn't see anything else)
• CPUID instruction: introduced in i486SL, later (1993 or 1995 and later) re-integrated into DX and SX (as "SL Technology")

Pseudo:

If (CPUID) -> continue as-is (supports only leafs 0,1, will have to add more models)
else if (FPU) -> Likely i486SL or i486DX
else -> Assume i486SX

[dd86k]

Dropped due to OMF deprecation. This will be backported to my SYSLORE project.