interesting DEC Pro stuff on eBay

Sean Conner spc at conman.org
Thu Apr 21 18:12:07 CDT 2022


It was thus said that the Great Mike Katz via cctalk once stated:
> 
> I could spend pages just describing how the 68K chip just blows away the 
> 8086 considering they were both released at about the same time.

  Agree here.  I loved the 68K and have fond memories of writing programs in
it.  But while the x86 has been Frankensteined into 64 bits, I don't think I
can see the 68K ever being a 64-bit architecture.  I don't think there are
enough unused bits in the instruction formatting for that.

> For crying out loud the 6809 even though it only addresses 64K is a more 
> powerful processor than the 8086.  Even with the 8086 clocking faster 
> than the 6809.

  As much as I like the 6809 [1] I think you are overselling it vs. the
Intel 8086.  Both only support a single IRQ [2], but the 8086 has more
registers, and with the segmentation, you can have split code and data of
64K each.  On the flip side, the 6809 does have some sweet addressing modes
(especially indirect indexed) and easy position independent code (love
that).  

  -spc (And I've written assembly for all three architectures)

[1]	I even wrote an emulator: https://github.com/spc476/mc6809

[2]	Okay, technically, the 6809 also has a "fast" interrupt, which only
	saves the PC and CC registers.


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