New milestone: I just wrote 150 LoC of glorified machine code (utterly unsafe; lots of magic numbers) and had it work the first time.

https://github.com/akkartik/mu/commit/c8784d1c0f0

Though to be fair I'd been planning it for 16 hours, with lots of preliminary commits that nibbled away at the edges of the problem. Still, time spent thinking before rather than debugging after.

Perhaps this is bad news. Perhaps my brain is getting so colonized by machine code that I'm losing my bearings on what is easy for others.

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Lots of words in this commit message about liveness analysis, and it probably still makes no sense to anybody.

Hopefully it'll make sense to me at least in a month or two.

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OMG, check out this "spiritual fork" of Mu that's designing not just the entire software stack to fit in a single person's head, BUT ALSO THE PROCESSOR.

https://github.com/grokthis/ucisc/blob/master/docs/01_Introduction.md

Still super early days. There's a nascent VM. Needless to say, I'll be contributing.

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Update on the Mu computer's memory-safe language

Still no type-checking or memory-safety, but we have partial support for arrays and product types. Still several sharp edges:

• can't index an array with a literal
• can't index an array with non-power-of-2-sized elements
• can allocate but not use arrays/records on the stack

My todo list is growing. But work per item is shrinking. Hopefully there's an asymptote.

(More details. Repo.)

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Update on the Mu computer's memory-safe language

Mu just got its first couple of non-integer types: addresses and arrays. As a result, the factorial app can finally run its tests based on command-line args.

http://akkartik.github.io/mu/html/apps/factorial.mu.html

Addresses are accessed using a '*' operator. Arrays are accessed using an index instruction that takes an address (addr array T) and returns an address (addr T).

Literal indexes aren't supported yet.

Open question: indexing arrays of non-power-of-2 element sizes.

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My paper's been accepted!

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I'll be in Porto, Portugal on Mar 24 to present a paper on Mu at the Convivial Computing Salon.

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A brief timeline of the Mu computing stack

Jul 6, 2014: commit 0, tree-based interpreter for a statement-oriented language

Jul 19, 2017: commit 3930, start of SubX machine code

Sep 20, 2018: started building SubX in SubX

Jul 24, 2019: SubX in SubX done, commit 5461

Oct 2, 2019: started designing the Mu memory-safe language

Oct 29: started http://akkartik.github.io/mu/html/apps/mu.subx.html

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The Agaram Paradox: to get to better interfaces, expose your implementations.

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I just wrote up a cheatsheet of all the instructions supported by Mu (best on a wide screen/window):

https://raw.githubusercontent.com/akkartik/mu/master/mu_instructions

It's not clean. Mu isn't a clean, well-designed language. Because it's designed to map 1:1 with x86, and x86 is not a clean, well-designed instruction set.

But this sort of 1-page summary of a compiler is something I've always wished I had. Something that doesn't tell you what to type out and then pretend you understand compilers.

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