jecel

9 ms·

31.
by jecel 1y ago
Very good points. About ARM1, 2 and 3, if my memory from 4 decades ago is correct then the changes from 1 to 2 were a move to a slightly newer process node, replacement of "multiply step" with actual multiply instructions and the
32.
by jecel 1y ago
Thanks for the link. As Ken points out at the end, "Probably the biggest objection to calling the ARM1 microcoded is that the designers of the ARM chip didn't consider it that way.[4] Furber mentions that some commercial RISC proc
33.
by jecel 1y ago
ARM1 had multicycle instructions (LDM and STM) and the ARM2 added more (MUL and MLA) but as far as I know these were controlled by hardwired finite state machines, not microcode.
34.
by jecel 1y ago
ARM only shows up on a white board on the background of a discussion towards the end. So it isn't 100% absent from this movie, but it is really about the conflict between Clive Sinclair and Chris Curry (just like "Pirates of Silic
35.
by jecel 1y ago
"IBM had no moat around the PC." is true about the original PC and XT, but they did have 7 patents on the AT. After the PS/2 attempt didn't work out, their lawyers spent the first half of the 1990s going after the chipse
36.
by jecel 1y ago
Yes, I only tested the 60Hz vertical refresh options.
37.
by jecel 1y ago
Thanks for the link. I meant to write 1280x720@60Hz for 16:9 HDMI TVs/monitors but have used 1024x768 quite a bit in the past for 4:3 VGA monitors and ended up mixing the two. VIDEO_ID_CODE 4 (1280x720) works on all monitors I tested w
38.
by jecel 1y ago
Though DVI/HDMI monitors are supposed to handle 640x480, over half of the ones I have tested don't display anything. Every single one of them worked just fine at 1280x768, however, so I am changing my projects to use that.
39.
by jecel 1y ago
Please note that RISC-V and RISC5 are different projects: https://riscv.org https://riskfive.com Despite the name of the second site, the actual processor is called RISC5 (see the menu on the left) and is part of the
40.
by jecel 1y ago
The 2022 PhD thesis linked from their web site includes a picture of what they claim was an actual chip made using a 22nm process. I understand that the commercial chip might be different, but it is possible that the measurements made for t
41.
by jecel 1y ago
By original MIPS designers do you mean from Stanford? Those would include John L. Hennessy, Norman P. Jouppi, Steven Przybylski and Christopher Rowen as the authors of the first papers about the project. If you are talking about the MIPS co
42.
by jecel 1y ago
SPIM was the name of a MIPS32 simulator widely used in computer science research at one point: https://spimsimulator.sourceforge.net/ RISC-V looks a lot more like MIPS than it does RISC-I to IV, so on the technical side hav
43.
by jecel 1y ago
You have to manually carve up the heap into arrays if you want to have more than one. If variable F points to the start of an array then F,I@ will read F[I] while 42!(F,I) is an assignment F[I] := 42. The comma operator is just to convert a
44.
by jecel 1y ago
Thanks for the link - at the time I did a quick search and didn't find that or any other language with that name. The 1KB target was for Baby 8 (the associated processor) binary code. That processor had a few quirks (like only indirect
45.
by jecel 1y ago
Not yet, and if I publish any of the languages I will probably use a different name (like "Oak" -> "Java"). Though I did call the unfinished language I published "BLA" (Baby 8 LAnguage - an attempt to see if
46.
by jecel 1y ago
I have named the experimental languages I am toying with "Plan <x>" (for Programming LANguage, but also because it is a good term as you pointed out). Originally I was using numbers (probably would skip "Plan 9" li
47.
by jecel 1y ago
Sun's project was an attempt to have a high performance Java processor to replace the simpler PicoJava: https://en.wikipedia.org/wiki/MAJC
48.
by jecel 1y ago
The Xerox Dorado, an ECL beast evolved from the Alto, was considered the only machine to offer a good Smalltalk experience when Smalltalk-80 was initially released. The Xerox Dolphin, for example, was only about "0.1 Dorados" desp
49.
by jecel 1y ago
The Alto created the image from a display list, like the Atari 800 or the Amiga. So you could have a wider rectangle on most of the screen for pictures and a narrower rectangle at the bottom for displaying status. It was not up to showing o
50.
by jecel 1y ago
Didn't the TMS 1000 include the processor, i/o, ROM and RAM? All that in 8K transistors seems frugal.
51.
by jecel 1y ago
https://www.researchgate.net/publication/2737441_An_Evolved_...
52.
by jecel 1y ago
I was disappointed to find that half of the monitors and TVs I tested don't show 640x480 HDMI though all of them worked at 1280x720. So I am redoing a project I am working on to use the higher resolution.
53.
by jecel 1y ago
The 68000 actually had three 16 bit ALUs, so could munch a peak of 48 bits per clock cycle. Only one could do all operations while the other two were basically just add. These days we would say there were part of the AGU (address generator
54.
by jecel 1y ago
He was: he pointed out that the world of computing he (we) knew back then is illustrated in all the ads. Note that August 1981 is also the month the original IBM PC came out. In contrast the articles showed a world of computing with mice, o
55.
by jecel 1y ago
Much of the memory in a Lisp program is in the form of CONS cells, so the MIT LISP machines had a compact way of encoding this. They also used tagged memory to be able to handle the different kinds of data at runtime. They inherited a very
56.
by jecel 1y ago
As far as I know the Tektronix Smalltalk computers (4404 and later) were the only ones to try a higher resolution scrolling virtual screen. For Alan Kay's talk they removed some limits of the original hardware, like screen size, proces
57.
by jecel 1y ago
Squeak runs just fine on Linux computers (among many OSes) including the Raspberry Pi. The project you linked to recreated the original Xerox Smalltalk-80 on the Pi. It has a rather limited scope so I don't know if they ran out of stea
58.
by jecel 1y ago
While (+ 1 2) doesn't work in the basic system, it is possible to extend it entirely in Lisp so that it does work. You could use Church numerals to represent the numbers, for example. I once did it by representing numbers as lists of h
59.
by jecel 1y ago
For a serial computer, an oscilloscope will easily do what a set of blinking lights will do for a parallel computer. By trading time for space it gives you a free serial to parallel conversion.
60.
by jecel 2y ago
All 32 bits in the ARM1 and 2 were used to address data, so in theory you could have 4GB of RAM. But these processors only had 26 address pins, so that would give you at most 64MB (similar to the 24 address pins in the 68000). If you used t

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