klelatti

53 ms·

1. 841.▲
   The First RISC: John Cocke and the IBM 801(thechipletter.substack.com)

   80 points by klelatti 4y ago|87 comments
2. 842.▲
   by klelatti 4y ago

   Thanks so much. Will do!
3. 843.▲
   by klelatti 4y ago

   x86-64 was released in 1999. Is it incomprehensible that you're probably buying a computer with an x86-64 processor in 2022? ;) More seriously computers are being sold today with CPUs with the same performance as those available seven
4. 844.▲
   Writing IBM S/360 Assembly By Hand(thechipletter.substack.com)

   2 points by klelatti 4y ago|0 comments
5. 845.▲
   by klelatti 4y ago

   Thanks for the thought provoking original comment!
6. 846.▲
   by klelatti 4y ago

   Thanks!
7. 847.▲
   by klelatti 4y ago

   Brilliant! Thanks so much.
8. 848.▲
   by klelatti 4y ago

   Interesting comment but the link brings up a 404 now for me.
9. 849.▲
   by klelatti 4y ago

   Can you expand on the explanation as to why Intel said they designed the 286 as they did?
10. 850.▲
    by klelatti 4y ago

    One question which someone might be able to help with. The 6502 was the third CPU the team designed. Second was the 6800. But the first was also made by Motorola but as a one-off for Olivetti I think. Does anyone have any details of this CP
11. 851.▲
    by klelatti 4y ago

    Thanks. I feel really bad about my pedantry now! I didn’t know that she’d carried on maintaining BBC Basic for so long after the BBC Micro era. Funnily enough I downloaded that ARM assembly language book last week in the course of writing u
12. 852.▲
    by klelatti 4y ago

    Maybe, but not before she designed the Arm instruction set which is what the parent comment says (possibly I'm being pedantic but it does make a mess of the whole chronology).
13. 853.▲
    by klelatti 4y ago

    Agreed on the sentiment but 'fifteen years' on BBC Basic can't be right. More like a couple of years. Great presentation from Sophie here. https://www.youtube.com/watch?v=6lOnpQgn-9s
14. 854.▲
    by klelatti 4y ago

    Thanks so much for coming back. I wondered if I was missing something in what Hermann was saying! It must have been interesting to work with Sophie. I remember looking at some disassembly of the BBC Basic 6502 code and being fascinated by h
15. 855.▲
    by klelatti 4y ago

    That might be the perception inside Apple but I'm certain Arm was planning to build a 64 bit core anyway and would expect to work with leading customers on its development. So calling it 'the Apple ISA' is overstating it a bi
16. 856.▲
    by klelatti 4y ago

    Source?
17. 857.▲
    by klelatti 4y ago

    But the 68000 dates from 1979 before even the first RISC architectures made to market. Competition was 8088. SGI for example dropped 68k range in due course for MIPS. What makes ARM interesting to me is that it applied RISC principles in a
18. 858.▲
    by klelatti 4y ago

    Said the team liked it but wanted address and data bus demultiplexed - but the 286 already has demultiplexed buses unlike the 8086. Maybe I misunderstood! It’s here I think: https://m.youtube.com/watch?v=w1HODsDGMzI
19. 859.▲
    by klelatti 4y ago

    Thanks!
20. 860.▲
    by klelatti 4y ago

    Wind, Sand and Stars just may be my 'Desert Island Book'. Probably not as well known in the English speaking world as it deserves to be.
21. 861.▲
    by klelatti 4y ago

    Apple can use Arm today because TSMC offers leading edge fabrication. It almost certainly couldn't do before because it would have had to use an uncompetitive node the compared to say Intel. Plus Apple now has the cash and design team
22. 862.▲
    by klelatti 4y ago

    This is a great link. Really liked the section > Now, the aforementioned, Arthur Norman, who had written the LISP interpreter for the BBC Micro, and was in and out of Acorn the whole time, had come up with a design for a machine with 3 i
23. 863.▲
    by klelatti 4y ago

    Agree 100% with the thrust of your argument but isn't the challenge still there today for a Cortex-M0 equivalent say?
24. 864.▲
    by klelatti 4y ago

    > Entirely different market 320xx vs ARM (at the time and even now). The simplicity you're advocating as successful for ARM was not applicable for the market NSC was attempting to compete in. Except the original IBM 801 RISC was bui
25. 865.▲
    by klelatti 4y ago

    Saint-Exupery?
26. 866.▲
    by klelatti 4y ago

    The thing that has always impressed me about the ARM1 is that they didn't just take the RISC model from the papers they read: they adapted it to suit their own needs. Adding the barrel shifter, conditional execution, removing features
27. 867.▲
    by klelatti 4y ago

    I think it might have been Andy Hopper who pushed the RISC papers forward (IBM / Berkeley etc). There is an interesting interview with Hermann where he says that Acorn asked Intel for a special version of the 80286. I've always be
28. 868.▲
    by klelatti 4y ago

    Interesting thanks.
29. 869.▲
    by klelatti 4y ago

    Very good! Just need to get RISC-V in there now too.
30. 870.▲
    by klelatti 4y ago

    Very cool! What's the software stack?