Re: 6502 illegal opcodes questions

[Jim Brain <brain@jbrain.com>]

Michael J. Mahon wrote:
> And just "getting it done" with absolute minimal die size *is* a design
> culture.  (One that is no longer current in commercial microprocessors.)
True.  At the time, cost was the absolute concern.  8080's were hundreds 
and 6800s were as well.  MOS wanted a $20.00 or so CPU, to undercut the 
market.  die size meant a lot.  MOS had just hired the 6800 design team 
not too much earlier, and did not have a NMOS process in place when the 
design team came onboard.  They no doubt wanted to cram as much into a 
die as they feared the yield would be low on the first batches.

Jim