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| Authored by: Anonymous on Monday, April 08 2013 @ 09:08 AM EDT |
Microcode could be embedded as firmware or not. All depends on the system
and application. Some people may remember it as bit slice. [ Reply to This | Parent | # ]
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| Authored by: Anonymous on Tuesday, April 09 2013 @ 10:09 PM EDT |
Yes it does bring back memories. Now the terms seem to be interchangeable
depending upon to whom you are talking to.
Which term you use I think was just internal semantics according to the
companies at the time. My first job was logic design and
"micro-coding" a couple sub-stages of a huge MIMD pipeline graphics
processor implemented in TTL and ECL SSI and MSI(when we could get it!)logic. To
us, Microcoding was pure embedded logic using an array of bipolar proms (this
was even before PALs and FPGAs). ALL the machine state was feedback into the
prom as an "address" and the computational result was emitted in a
single clock cycle. Each level in the pipeline line executed a single
instruction per clock - a classic Moore machine. All next state decision and
branching logic was hardwired. This was San Jose, home of the Floppy disk. The
local ex-IBM guys called this "microcode" as opposed to
"Firmware" which was a hardwired non-volatile bootstrap program which
read the floppy.
By the way to us "old timers" who implemented these programmable
machines, all software really is mathematics we had reams of logic tables in our
files to prove it.
[ Reply to This | Parent | # ]
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