#ISA #architecture comparison between amd64 and ARM64 by David Chisnall on #Mastodon, reporting on research he did at Microsoft finding, among other things, that ⅔ of values are used exactly once
on 02026-07-17#PDF scan of the #paper on the design of the 20-bit bit-serial “MP944” CPU from 01971, part of the #CADC, which sure doesn’t sound like a microprocessor to me, despite the domain name.
The multiplier (“PMU”) was a 28-pin DIP, the divider (“PDU”) was another 28-pin DIP, the “special logic [functional] unit” was another 28-pin DIP, and the “steering unit” (of which there were three, one for each of the previous three modules) was another 28-pin DIP, and there were 19 vertical-microcode ROM chips: “Each functional unit is controlled by its own micro-instruction ROM.” To me it sounds like there were at most three CPUs, each consisting of a steering unit and either a multiplier, a divider, or a “special logic unit”, and maybe just one CPU split across 25 chips; when the paper uses the term “CPU”, it seems to be referring to all of these functional units together and perhaps the ROMs as well, not just one of them.
Moreover, the multiplier and divider just blindly did a multiply and, respectively, a divide, every “frame”. Only the “special logic function” could do “Conditional, and Unconditional data branching”. And all three “functional units” were controlled by some control bits from the “system executive control”, a group of ROM chips.
The “steering unit” was a “three channel serial digital data multiplexer” with three outputs which could add or subtract data under the control of part of the instruction word on its way to the PMU, PDU, or SLF.
It seems like the program counter, or rather counters, were located in the microcode ROM chips, which could increment them or reset or reload them under the control of some control lines. #hardware #architecture #history
on 02026-05-26#Chuck-Moore and C.H. Ting advocating the #MuP21 in somewhat unjustifiable ways in 01995. #architecture #stack-machines #hardware
on 02026-05-26#PDF scan of #history of the #JOHNNIAC, where #JOSS and Newell, Shaw, and Simon did some of the earliest #AI work including GPS (the General Problem Solver). Von Neumann’s paper on the #architecture (long before “architecture” was invented) is included as an appendix.
on 02025-08-03#PDF of the #documentation for the Zenrom addon to the #HP #41C pocket calculator or handheld computer from 01979, documenting its CPU instruction set, etc. #retrocomputing #history #architecture
on 02025-07-23John Mashey (not Andy Glew) on what RISC really means, the definition of RISC, posted originally to comp.arch, with the awesome addressing modes table. #architecture #history
on 02025-07-10IBM 360 #retrocomputing #architecture.
on 02025-07-09How the 486 (and 8086, etc.) instruction set #architecture is secretly octal.
on 02024-12-19#PDF #paper on the #Kronos high-level CPU #architecture from the 01980s, influenced by Oberon.
on 02024-11-03John Mashey on #RISC vs. CISC and in particular why the #VAX was doomed. #architecture #history
on 02022-10-12More on #Chuck-Moore, #Forth, and #hardware, up to #GreenArrays (as of 2013). Especially in the comment thread. #stack-machines #architecture
on 02017-08-06book “Unpleasant Design” describes #architecture designed to restrict its use (e.g. park benches with intrusive armrests). Lots of photos, some videos in this review.
on 02016-11-21"Tenara" is an architectural #textile woven of expanded polytetrafluoroethylene (PTFE, teflon) fibers, with a lifetime of 25 years or so in the sun. #architecture #materials
on 02016-06-28a comment on the human benefits of gradual rather than sudden failure, in the context of #plumbing in #architecture. I think he’s talking about the polybutylene piping catastrophe.
on 02016-06-26#Concrete #materials suffer #carbonatation more rapidly in today’s 400ppm CO₂ climate, and some #architecture designed for 75 years will start to fail in 50 or 60.
on 02016-06-26long-secret #subterranean Damanhur temple #architecture
on 02015-12-22The Grasshopper #3D algorithmic modeling extension for Rhino has been used for a bunch of #architecture, which is roughly as trippy as you would expect.
on 02015-12-04with the “coelux” sunlight simulant we can build “earthscrapers” rather than skyscrapers. No word on how the collimation and cooling work. The light is from LEDs. US$60k a pop. #hardware #architecture
on 02015-11-18the 64-bit/20-bit/4-bit BCD nibble-based CPU #architecture of the #HP 71B handheld BASIC computer from 1984, of the HP 48G, and produced in #hardware up to 2003
on 02015-08-05