15 March 2025 - 21 March 2025

Table of Contents

1. LECTURES IN DISCRETE MATHEMATICS

https://cseweb.ucsd.edu/~gill/BWLectSite/

1.1. Investigated boolean function minimization

2. GMPASM assembler

2.1. coverage tests for integer binary operations

2.2. simple coverage analysis tool

3. Sonic Fiber

3.1. rsyncing status page to g1

better then nothing for waiting a week to get to SJ to update the address.

3.2. exposing by hand via barelyworking.com

3.3. IP addr changes every power outage

Probably should get a UPS

3.4. bind notifies not working

need to debug

4. Night Light

Was stuck on - now burned out. Looks like the SCR has an anode-cathode low impedance path. Amazingly enough, the SCR it uses is still available from Digikey.

5. Sparkfun Addressable LED

5.1. Prototype for Kevin. Using Arduino build system with FastLED library.

5.2. Works with RIOT OS.

6. Stalled project review

6.1. Garden orb

Can't find the glass orb, so don't worry about it until it's found.

6.2. Brini-tracker

Better to use an integrated hand-held device (pinephone64 or similar). Maybe use the GPS modules for a local NTP time server.

6.3. Coil piano

Totally a victim of analysis paralysis.

6.3.1. Investigated beagleboard

Could use PRU for PWMs or wide SPI bus. Not sure if the effort is worth it relative to other appoaches; PRU code, linux audio device driver, bandwidth between ARM core and PRU, etc. Could be interesting; is it more interesting than other stuff?

6.3.2. STM32f676zi

Could get ~26 PWMs of various quality on board. Plus two 12bit DACs, a SPI port for a SPI based DAC, and a async memory bus for discrete DACs. Haven't finished pin assignments.

7. GMPForth

7.1. QEMU linux targets

…now segfault. Need to debug.

7.2. QEMU bare-metal targets

Starting to think about appoach. May start with running under u-boot to ease the inital effort of CPU initialization.

7.3. Multitasking

7.3.1. How would a classic round-robin multitasker interact with multiple cores?

7.3.2. Any insight from CSP or the Golang concurrency model?

7.3.3. Continuations?

8. SJ grounds

nothing going on…

9. Lapuz Peking/Panerus

Laid out keys. Keys are too big for Burhan's "restaraunt" cases. Ray to think about the next steps. Haven't heard anything back in months.

10. Mill

10.1. Supposedly working now.

10.2. Except I can't get it to turn on.

There's some trick I'm missing: apparently the controller is powered off the 220V, not a separate 110V like before.

11. EDA workflow

11.1. FPGA programming

11.2. RV32I

Seeing if a very simple RV32I is possible at ~600 ice40 cells. Likely not possible with a barrel shifter unless a multiplier is used. Certainly won't be fast, if possible at all at this size. This comes out to 18 gates per bit, which seems to be a ridiculously low number. Need to refine counting methodology to count LUTs and flops separately. Maybe further refinements for post-placement utilization (for example, how many LUTs get combined with a flop vs. separate LUTs and flops).

11.2.1. 'almanor' RV32I

  1. Three port register file, simplify decoder (~1100 LUTs, 300 FFs, 4 BRAM)

    Not too happy with the result. Messier than expected.

  2. Refactoring

    Still trying to understand what's driving the gate count. need to do some scaling experiments (FF/LUT per bit for various constructs).

  3. Post-synthesis testbench

    Fragility much reduced after aggressive process splitting.

  4. Verilator testbench

    Started planning.

  5. CSR/Debug interfaces

    Seeing if it's worth it to implement minimal CSR and debug interfaces

  6. Picosoc analysis

    Understanding picosoc implementation as a reference

  7. Standard tests
    1. riscv-arch-test

      Ported and running. After changing verilog memory image generation to use objcopy, and correcting JALR masking, all RV32I tests pass.

    2. riscv-torture
      1. Used picorv32 patches to generate test cases.

        Tried generalizing the Scala code, but looks like it was going to require more changes than I was comfortable with making - particularly for the E reduced register profiles.

      2. Regex filter

        Wrote a regex based filter to change opcodes and various ranges for RV32I, RV32E and RV64E.

      3. Tests pass

        All torture tests pass.

  8. Compare with a pipelined implementation

    Still thinking about it.

  9. Debug and Interrupt architecture

    Working out what's needed.

11.3. RTX-2000

Pulled out the RTX-2000 manual. Going to be a slog if I do it.

11.4. Synthesizable sparc v8

11.4.1. Seeing what it takes to make 'bs' synthesizable.

No way. Need to start fresh.

11.4.2. make smaller than picorv32?

Want to see if I can get something substantially smaller than picorv32 - although I doubt it. Better to start with RV32I though.

11.4.3. Found a bug

in load base/offset register instructions.

11.4.4. Found maybe another bug

Not sure about condition codes on 'sub'. Difficulty porting to rv32 leads to questions.

11.4.5. Cleanups

Apparently never run though verilator. Cleaned up.

11.4.6. Need legion

Need to see if the UltraSparc 10 is still running for legion tests.

11.4.7. u10

  1. Serial port works so boot is trying to do something.
  2. Doesn't seem to respond to 'break'

    Enhanced 'sp' to send break command.

  3. NVRAM battery is dead. Not a FRU.

    Needs an invasive fix or part replacement. NVRAM held MAC address, so that would be unavailable so could explain not booting. DHCP database has programmed MAC for static IP assignment so that at least is recoverable.

  4. Video dongle.

    Dongle works with VGA monitor. Updating NVRAM parameters on console allows system to boot.

  5. Recovered legion

    Copied off legion simulator binaries.

12. Spark/QEMU

Tested QEMU sparc simulator running Solaris 5. Probably a reasonable alternative to using u10.

13. Cross compilers

13.1. Toolchain scripts running.

13.1.1. moxie-elf c, c++, and ada.

13.1.2. sparc-elf c, c++, and ada.

13.1.3. riscv-elf c, c++, and ada.

gdb riscv simulator seems to not handle logical right shifts correctly in 32 bit mode. Arithmetic right shift has specific checks for 32 bit mode, but logical right shift does not and is clearly right shifting a 64 bit value.

14. SCZ Front Step

14.1. Starting to fit.

Hanging up on something hidden.

14.2. Need to fix mistake under window.

Have a patch piece.

15. Spacewire-like PHY

Poking that this long-standing problem. Building infrastructure to test if it's possible to construct a PHY layer with acceptable BER to 50 MBit which should be sufficient for 32 16-bit channels at 48 KHz sample rate. Need to re-establish EDA workflow.

Not sure this is practical.

16. CA Root Key Generation

Nice to have an appliance that manages keys. Need to make this simple. Really don't have time for a science project. Too, bad, though. It kind of is a science project. Could just buy something from nitrokey https://www.nitrokey.com/ but I really don't want to spend money on it of I have hardware already. Looking at nitrokey in more detail, it doesn't seem to be any simpler than what I'm doing already.

16.1. First pass done

16.1.1. Based on https://pki-tutorial.readthedocs.io/en/latest/simple/

Interesting that the certs generated fail with openssl sserver testing because the cryptographic algorithms are too weak.

16.1.2. Work continues

  1. Have an outline with ECDSA/NIST-384
  2. Have consolidated configuration across CAs.
  3. Trying to decide if/how to deal with revocation. What a PITA.

16.2. Need to be clear on security properties.

Definitely protect against remote access to private keys. How strong does the protection against local access need to be?

16.3. Simple hardware.

16.3.1. Use beagleboard with local interface

16.3.2. Use some modern device TPM

Need to export data for backup.

16.3.3. Or something that uses PKCS11 interface

16.4. USB Serial interface only but no credentials across USB I/F.

But this potentially exposes the hardware to remote access via the USB I/F when connected.

16.5. Use Sneakernet

Doesn't scale. Should use something so cert updates are automatable. But that's a science project it seems.

17. Compilers

17.1. Compiled Wikipedia PL/0 example

17.2. Work out overall plan.

Lots of moving pieces.

17.3. Looking into LLVM MLIR.

Will not use immediately, but perhaps trend in that direction.

17.4. ASDL

17.4.1. current smlnj C++ implementation incomplete

17.4.2. old versions asdl source fail to build with new versions of smlnj

17.4.3. old versions of smlnj not easily buildable on x8664

17.4.4. ancient binary of asdl 1.2 compiler seems to work

but associated libraries are to old to link because of missing ctype symbol

17.4.5. analyzing asdl 1.2 generated code

Most of the code is for serialization, which is going to be replaced anyway, so can be removed by hand.

17.4.6. run in vm?

Analysis of binaries shows that it was built on some redhat os using gcc 2.8.1. Redhat-6.2? No. Tried various ancient Redhat OSs.

18. Piper dovecot

18.1. Update broke dovecot auth.

Looks PAM related, but PAM update failed to fix.

18.2. Set tuffy up as a staging server

So I don't debug on 'production'.

18.3. piper dovecot SSL certificate NOT broken

At least not obviously broken (yet). Further investigation needed.

19. Various i686

19.0.1. netbsd

was installed. But needed the box for something else.

19.0.2. buildroot

builds complete.

20. piper

20.1. dovecot

20.1.1. Raising apparmor error.

Not sure how to resolve.

20.2. pidgeonhole

20.2.1. procmail replacement.

20.2.2. Considering integration.

20.3. httpd

20.3.1. Still stable.

But seems to occassionally mis-serve files.

20.4. SSL cert

Trying letsencrypt with certbot. http problem above may be interfering.

20.5. redmine

Still not sure I want to go down this rabbit hole.

20.6. openvpn

Need to consider cert construction.

21. Buffalo WZR-HP-G300NH

21.1. Update

Sometime next year.

22. SJC weather station

22.1. Proper enclosure mostly constructed

22.1.1. Needs a redo on bottom plate

22.1.2. Seems to have improved wireless connectivity somewhat

23. opencl

23.1. Studying. Have some examples working.

23.2. Need to look at arrayfire as an alternative.

23.3. This is a bit of a hammer looking for a nail.

24. EPLDH

24.1. MPFI interval arithmetic better alternative

25. wktpqb

25.1. needs a new approach

25.2. Verifying edge construction (con't.)

25.3. 'gcd' algorithm doesn't work

26. Virtual Orchestra

26.1. sfz file tests

26.1.1. need tooling to edit sample files

26.2. increasingly skeptical whether quality results are possible

26.3. maybe should treat as platform for concatinative synthesis

26.4. maybe should just accept the limitations and work with it

One should not be disappointed that a guitar can't sound like a flute.

27. gat

27.1. spectrogram done - matches 'octave' output

28. RIOT drivers

Implemented - needs testing.

28.1. WS2801

28.2. Velleman KA03

28.3. Velleman KA05

29. mcd05 32 button/led box

29.1. Recovered schematics.

29.2. Planning software.

29.3. Received STM32F767 Nucleo144 with Ethernet.

29.3.1. Test program running.

29.3.2. Need to consider CoAP multicast discovery.

29.3.3. Consider simpler architecture with STM32F767 as a 'hub'.

29.3.4. Consider CAN interface to hub.

30. AMD 2900 bitslice computing

30.1. Probably my oldest uncompleted project

30.2. Exploring possibilities for something constructive

Create verilog models for 2903/2910 and verify against hardware?

31. Hitachi HD68B09E CPU

31.1. RAM/UART/IO

31.2. Started schematic

31.2.1. Standard peripheral set for 8 bit CPU bringups

Board schematic planned - need Kicad symbols

31.3. Arduino Mega 2560 DMA loader

…Along with standard 8 bit loader

31.4. Generate quadrature clock directly

31.5. Full Bus SW Emulation infeasible

6809 1000ns maximum cycle time too short

32. Rockwell R65F11

32.1. Still evaluating.

32.2. Dev board

Reverse engineered some of a mostly fully built development board with one part missing. As near as I can tell, that one part is some sort of programmable address decoder with a pinout that does not correspond to any part I can find. Kind of like a GAL but with inputs on top and outputs on bottom (as opposed to left and right in a standard GAL). I have no idea what the provenance of this board is and if it ever worked.

33. PLD programming

Looks like Atmel 16V8 is the last 5V PLD part left standing. Maybe not surprising that there still doesn't appear to be a fully open source tool chain for programming. How hard could it be? (!) Could next-pnr generic help? Might be easier to use espresso for logic array and program output logic bits directly for simple stuff.

34. EPROM Programming

Found some software for Needham programmer. Need to check electrolytic caps on ISA board.

35. POSIT

35.1. Use POSITs for YRX?

No. Existing library is fine.

36. MAME

36.1. Subset builds in debug mode

Full debug fails - not enough disk or memory.

36.2. gs6809 serial IO doesn't work right with PTY and other streams

36.3. ampro (Z80/Z80SIO) does work with PTY

36.4. Evaluating what is needed for other emulators.

37. More project ideas

37.1. Zuse Z3 simulation in Verilog

Good excuse for floating point ALU design. Try posit format?

37.2. GMPForth ports to simulators

37.2.1. SIMH for some targets (vax)

37.2.2. MAME looks interesting for microprocessor system emulations

How to support ersatz systems?

37.2.3. Ports to classic figFORTH targets

37.3. Extracting ISO Superboard Forth ROMS for MAME emulation

37.4. 'bwocl' OpenCL tooling

37.4.1. Offline compilation

37.4.2. Standard Kernel Running

37.5. hardware support for classic 5V CPUs

37.5.1. RTX2000, CDP1802 still available!

37.5.2. 6502, 68000, 320C30, others on hand

37.5.3. CPUs with totally async bus may be supportable without RAM

37.5.4. Could use small footprint monitor in asm (gmpmon?)

37.6. Existing 'retro' hardware still working?

37.6.1. OSI Superboard

Unknown. Composite to VGA adapter didn't seem to work. Needs analysis. Found OSI model 610 board underneath!

37.6.2. Super Jolt

No output. Needs analysis.

37.6.3. Ampro Little Board

Not booting. Needs analysis.

37.6.4. Rockwell R65F11 Demo board

UART sending "NO ROM" at 2400 7N1 as expected with 2MHz xtal. MAME emulator possibilities?

37.6.5. NMIX-0016

Works. Found original prom in a parts stash(!).

38. David Davies

38.1. copped a deal - 8 years.

Author: Daniel Kelley

Created: 2025-04-05 Sat 06:51

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