“M” Performance… Pessimizations! or: SSE is a Scam.

This article is a continuation of the M series.

The vpatch given below entirely re-implements the TLB (MMU) of M to use SIMD instructions from the AMD64 SSE2 set.

Whereas previously TLB entries were kept in memory and searched iteratively, now we keep the Tags (3 byte each) sliced into three XMM registers, and search them in [...]

“M” Performance Optimizations.

This article is a continuation of the M series.

The vpatch given below speeds up the execution of M by approximately 30% (as measured by the Dhrystone benchmark.) It implements separate single-entry TLB caches for reads and writes; a set of fastpath exception handlers; and several other minor optimizations.

You will need:

A Keccak-based [...]

“M” Genesis.

M is a MIPS-III system emulator, written purely in AMD64 assembly to make optimal use of commonplace iron. As discussed previously.

M will run lightly-modified Linux kernels with strict logical isolation vs. the host (and vs. any other instances of itself.) That is, it in fact does exactly what e.g. QEMU fraudulently pretends to do.

To keep [...]

“Finite Field Arithmetic.” Chapter 18B: “Cutouts” in Peh.

This article is part of a series of hands-on tutorials introducing FFA, or the Finite Field Arithmetic library. FFA differs from the typical “Open Sores” abomination, in that — rather than trusting the author blindly with their lives — prospective users are expected to read and fully understand every single line. In exactly the same [...]

“Finite Field Arithmetic.” Chapter 18A: Subroutines in Peh.

This article is part of a series of hands-on tutorials introducing FFA, or the Finite Field Arithmetic library. FFA differs from the typical “Open Sores” abomination, in that — rather than trusting the author blindly with their lives — prospective users are expected to read and fully understand every single line. In exactly the same [...]

“Finite Field Arithmetic.” Chapter 17: Introduction to Peh.

This article is part of a series of hands-on tutorials introducing FFA, or the Finite Field Arithmetic library. FFA differs from the typical “Open Sores” abomination, in that — rather than trusting the author blindly with their lives — prospective users are expected to read and fully understand every single line. In exactly the same [...]

X-Ray Large-Format Kindergarten.

Below is the output of a new test-fire of the PCB radiography system, this time using FujiFilm “Super HR-T Medium Speed” (25×20 cm) film in place of the earlier self-developing dental Eco-30.

However, the time has not yet come to molest the MacIvory — first, we must characterize the film and the [...]

X-Ray Microscopy of Symbolics “Ivory” CPUs.

I currently have three Symbolics MacIvory CPUs. (Do you, reader, have one to sell? Please leave a comment!)

One is currently installed in a working machine and was not yet molested; the two remaining chips, I obtained in 2017 by bartering away a Symbolics 3620.

At some point I will cut one or more of the “Ivories” [...]

X-Ray Spectrography Kindergarten.

This article is a continuation of “X-Ray Microscopy Kindergarten.”.

Preliminary experiment with multi-energy x-ray (colour channel combination), distinguishing materials by absorption at different wavelengths.

The tube appears to exhibit some “heel effect” at the longer wavelengths.

Exposure: 75 sec. @ 35kV, 21kV, 20kV (R, G, B) [...]

X-Ray Stereography Kindergarten.

This article is a continuation of “X-Ray Microscopy Kindergarten.”.

Here, we see a stereo pair (approx. +/- 25 deg. one-axis rotation of the object from the horizontal plane, while film is stationary) of the device from before.

The vias are clearly distinguishable.

[...]

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