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Using clobber in machine descriptions

michaelh — Thu, 23 Apr 2009 20:22:02 +0000

‘clobber’ ensures that the register is free before entering and after exiting an instruction. Therefore you can’t use it to say a register is used then destoryed by an instruction such as LOADACC, (X+) on X.

Took a while to figure this out

Extreme optimisation

michaelh — Fri, 17 Apr 2009 07:40:46 +0000

GCC is crazy. It recognises a printf(’foo\n’) and turns it into the equivalent puts(’foo’) instead.

builtins.c has all types of similar transformations including printf(’%c’, v) to a putch(v) and printf(’%s’, v) to fputs().

Canterbury innovation incubator

michaelh — Sun, 05 Apr 2009 05:08:53 +0000

The Cii seems interesting. It needs more publicity - this is the first time I’ve heard of it in my fifteen years in Christchurch.

Adding new relocation types

michaelh — Mon, 30 Mar 2009 08:44:32 +0000

For bfd, add them to the comment block in reloc.c then run ‘make headers’. One more make after that gets it through to bfd.h

binutils / bfd target magic

michaelh — Mon, 02 Mar 2009 08:49:27 +0000

So the BFD architectures listed in bfd.h are actually defined archures.c in a big comment block at the start of the file. This is split out and fired into the documentation, many bfd-in-xx.h files, and finally into bfd.h.

Note that a ‘make headers’ doesn’t re-build it. I found a ‘make distclean; ./configure’ was the most brute force way.

Python on an embedded system

michaelh — Thu, 19 Feb 2009 07:17:49 +0000

I like Python. I want to use Python everywhere. Hmm. Sounds more like an addiction. 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. From there:

Stripping python saves 1.1M
Removing man and include saves 400k
Removing *.py and *.pyo saves 2.8M but still lets everything run
Removing Tk, Config, and stdwin saves 3.9M
Removing test saves 1.9M

This brings a fully working Python interpreter with all of the command line libraries down to 2.4M. Quite respectable.

Naming

michaelh — Sun, 01 Feb 2009 19:20:14 +0000

For personal reference. What happens when you follow too strict of a naming convention:

http://ws.apache.org/xmlrpc/apidocs/org/apache/xmlrpc/server/RequestProcessorFactoryFactory.html?rel=html

Hmm

michaelh — Wed, 26 Nov 2008 08:42:41 +0000

http://www.ladyada.net/make/fuzebox/index.html

and

http://www.makershed.com/ProductDetails.asp?ProductCode=MKPO1

Anthony’s

michaelh — Tue, 30 Sep 2008 03:27:51 +0000

…fish grotto on the bay in San Diego is very good.

They also do seafood.

Richard Stallman

michaelh — Sat, 16 Aug 2008 07:12:53 +0000

Saw RMS at Canterbury University today. He has an interesting point of view, very liberal, but also a point of view that is based on old technology.

He said that sites like Google Docs are a problem as you are running a program on their machine, a program that you don’t have control over. The solution is to install your own version on your own machine. I wonder how you can do this and still get the advantages of hosted software, such as lower cost, lower administration, and higher availability. I don’t want to manage any of the software I use, and one solution is to let someone else do it.

He’s not concerned about embedded systems where a processor is used instead of a dedicated circuit, such as in a microwave. However, my microwave gains time and I’d rather have it show time in 24 hours to match the stove. Both I could fix with the source. Then you have car computers such as the Nissan GT-R that changes the car response if it is on a race track. I heard a rumor of the NSX requiring you to take the car to the dealer if it goes anywhere near a known track.

Hmm. Perhaps the embedded/mechanical equivalent is the Maker Bill of Rights from Make Magazine.