[HN Gopher] A Brief History of Microprogramming (2022)
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       A Brief History of Microprogramming (2022)
        
       Author : fanf2
       Score  : 37 points
       Date   : 2024-09-25 09:54 UTC (1 days ago)
        
 (HTM) web link (people.computing.clemson.edu)
 (TXT) w3m dump (people.computing.clemson.edu)
        
       | nxobject wrote:
       | Just to add a few more resources - ye olde digital design books
       | are really fun to learn how (sequenced) microcoding was seen as
       | one of the highest-level tools in the toolkit of digital design
       | in general up to the early/mid 80s:
       | 
       | - "Computation Structures", an old MIT course book, which uses a
       | pedagogical processor similar to a microcoded PDP-11 or a 68k, to
       | illustrate microcoding as the highest level of digital design -
       | the processor they implement used a two-level microcoded
       | processor to implement two types of processor on the same
       | microcode interpreter engine, complete with built-in
       | monitor/debugger.
       | 
       | - "The Art of Digital Design", an older course text, which
       | culminates in the implementation of a PDP-8 clone;
       | 
       | Finally, if it helps look up more literature, another name for
       | microprogramming in the literature is "interpretive microcoding"
       | - one that makes the distinction between ye olde microprogramming
       | and modern "microoperations" pretty clear.
       | 
       | It also clarifies why two-level micro-coding might exist,
       | especially in the microarchitecture of the original 68k: you
       | write in high-level microcode an engine interpreting a target
       | ISA; this high-level microcode interpreter is then interpreted by
       | low-level microcode that directly activates control lines. Two
       | levels of interpretation seems baroque, but somehow it was fast
       | enough for 68k workstations.
        
         | kjs3 wrote:
         | Completely agree. It is regrettable how few of the old papers
         | are accessible now, either hidden behind paywalls or moldering
         | in some library basement unscanned.
        
       | dang wrote:
       | Related. Others?
       | 
       |  _A brief history of microprogramming (2005)_ -
       | https://news.ycombinator.com/item?id=32149149 - July 2022 (1
       | comment)
       | 
       |  _A Brief History of Microprogramming_ -
       | https://news.ycombinator.com/item?id=11412846 - April 2016 (8
       | comments)
        
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       (page generated 2024-09-26 23:00 UTC)