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Posts from ‘July, 2009’

Impressed with Tk 8.5

I’m quite impressed with the native theming changes that were made in Tcl/Tk 8.5.  Compare the Syscomp Design Oscilloscope under Tk 8.4 with ActiveTcl 8.5: Nice fonts, nice widgets, better packing, and much closer to the desktop theme. I’ve used Python’s Tk interface before for small, quick applications but have always been put off by [...]

Funny things with slow builds

I noticed something unexpected when building GCC today.  My triple core AMD desktop machine would build the compiler in 55 s but a new, decent-ish dual core laptop was taking about 200 s.  The problem turned out to be the on-demand CPU governor which, due to me ‘nicing’ the build, was idling the CPU along [...]

Simulator performance #2

A bit more work on the threaded version brings us up to 54.9 million instructions/s.  The interesting thing is that an average of 6.75 instructions are executed in a row before some type of branch.  This seems high enough to justify a simple JIT that converts a branchless sequence into native code… These changes however [...]

Simulator performance

I’ve been looking at a instruction level simulator for a processor with a simple instruction set.  The first version was written with an eye towards being turned into a hardware level emulator with basic instruction level timing.  This lead to a simple switch based dispatch loop: uint8_t op =; switch (op) { case 0: [...]

Building dalvik by itself

Just some notes for now. After following the instructions at you’ll have a local copy of the full android source code. We’re only interested in dalvik so we’ll skip building the rest. First switch to the 1.5 release tag. The first version that I pulled had a typo that stopped the build.  To do [...]

Python in deeply embedded systems

I like Python and would like to use Python everywhere. The question is, is Python suitable as a glue language on a embedded Linux system? With a few hacks Python 1.5.2 cross compiles just fine. The speed will be acceptable so it’s really only the size that matters. A standard build under x86 is 12.6M. [...]

The many languages of C

It’s time to buy a few more books for the library. While browsing through Amazon I came across this: Scroll down a page to see the 38 different covers from all around. It’s quite impressive – the low cost, orange covered Hungarian version looks like a find. My previous employeer had one of the [...]