Posted by Nikolaus Gradwohl
Wed, 25 Feb 2009 04:37:00 GMT
a while ago i read the really cool tutorial on programming a pdp11.
after typing the "hello world" example into the simulator, i startet to search for
instructions how to write the machine code for the pdp11 myself.
after a while coding in raw octal numbers, i wanted to take it to the next level and
searched for a way to write machine code by hand for my linux box
So i downloaded
Intel Architecture Software Developer's Manual, Volume 2: Instruction Set Reference Manual
and wrote a shell script that can be used to dump the raw machine code into a
file. of course my dualcore-pentium-mega-bla processor in far more sophisticated than
the pdp11 cpu was. so it can't be programmed in octal numbers - i used hexadezimal numbers :-)
execute the shellscript and pipe it into a file
sh dump.sh > hello
make it executable and - TATAAAA - a hello world programm in 120 bytes (including the
elf header - which adds 80 bytes all by himself)
# write a elf header in the file
echo -ne "\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00"
echo -ne "\x02\x00\x03\x00\x01\x00\x00\x00\x54\x80\x04\x08\x34\x00\x00\x00"
echo -ne "\x80\x00\x00\x00\x00\x00\x00\x00\x34\x00\x20\x00\x01\x00\x28\x00"
echo -ne "\x03\x00\x02\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x80\x04\x08"
echo -ne "\x00\x80\x04\x08\x6f\x00\x00\x00\x6f\x00\x00\x00\x05\x00\x00\x00"
echo -ne "\x00\x10\x00\x00"
echo -ne "\x31\xc0" # clear eax
echo -ne "\x50" # push 0 on the stack
echo -ne "\x68rld\x0a" # push the string onto the stack in reverse order, 4 bytes a time
echo -ne "\x68o Wo"
echo -ne "\x68Hell"
echo -ne "\x89\xe1" # move stackpointer to ecx ( the start of our string )
echo -ne "\xb0\x04" # move 4 to al ( eax is already 0 because auf line one )
echo -ne "\x33\xc3\xb3\x01" # xor ebx and move 1 to bl
echo -ne "\x32\xc2\xb2\x0c" # xor edx and move 12 onto dl (length of the string )
echo -ne "\xcd\x80" # int 0x80
echo -ne "\xb0\x01" # move 1 into al
echo -ne "\xcd\x80" # int 0x80
Tags asm, helloworld, machinelanguage, x86 | 1 comment | no trackbacks
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Posted by Nikolaus Gradwohl
Sun, 15 Feb 2009 07:15:00 GMT
I made a new version of the ical flowers sketch
i wrote in dezember. This time it doesn't only show a flower for every event in my calender, it also shows
- the current weather (using the rubyweather library)
- the current temperature outside
- the min/max temperature outside
- the current temperature inside ( using my arduino i2c thermometer sketch)
- the sky color changes depending on the current time
the system consists of a ruby-proxy, an arduino sketch and a processing sketch.
the ruby proxy starts a web-server on port 2000. It fetches the current weather using the
rubyweather gem, fetches the events from the configured caldav calenders, and
fetches the current temperature from the arduino using ruby-serial
the arduino sketch is basicaly the same as in this blog post. the only change is
that the arduino only sends the temperature when the host sends a 'C' over the serial line
the processing sketch finally fetches the data via http from the proxy and displays it ( using my icap4p library.
the screen is updated every 1/2 hour using the method described here
the code can be downloaded here
it's published under the LGPL
have fun :-)
Tags arduino, caldav, calendar, i2c, ical, ical4p, processing, ruby, visualization | no comments | no trackbacks
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Posted by Nikolaus Gradwohl
Tue, 10 Feb 2009 17:26:00 GMT
a while ago i posted images of my download-bots.
this december my parents used them as their
xmas-tree decoration.
now i have written some instruction to enable my dear reader to build his own download-bot - prefereably
while downloading a big file.
i use 2 strip of wood one 2cm x 4cm, and the second one 1cm x 0.5cm
- cut a 2 cm long block from the bigger strip for the head
- cut a 4.5cm long pice from the bigger strip for the body
- cut 4 2.5cm long pices from the smaller strip for arms and feet
- cut a 1 cm long pice from the smaller pice for the nec
- now glue the pices together following the instruction graphic bellow.
- put 2 pins into the head as antennas
- and finally draw a funny face on the head block
é voilà - a download-bot!
i really would like to see a comment if you have build your own bot
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Posted by Nikolaus Gradwohl
Tue, 10 Feb 2009 02:13:00 GMT
on saturday i was asked by a ruby-newbie (sorry - i had to write it :-) ) whats the difference between
a symbol, a string and a constant in ruby. even tough there are realy, realy many articles about ruby symbols
( a google search for "ruby symbols" results in 1,340,000 hits - so this is the 1,340,001 aricle covering the
topic) there is obviously still some confusion out there. So i try my own definition here.
Read more...
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Posted by Nikolaus Gradwohl
Mon, 09 Feb 2009 17:48:03 GMT
i have played a bit with python3.0 and this are the things that catched my eye:
- the new print syntax
- the exception-handling
- decorators
- the new io module
- classes in python
are no complete list of changes between 2.5 and 3.0 - and don't want to be.
they are just a list of thing's i noticed. Some of them are already present in python 2.6 but i newver used
that release - so i don't realy know.
Read more...
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Posted by Nikolaus Gradwohl
Sun, 08 Feb 2009 11:53:48 GMT
a friend of mine found another monster - this one tried to camouflage as a tree
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Posted by Nikolaus Gradwohl
Fri, 06 Feb 2009 17:29:01 GMT
my latest processing-sketch is a generator for abstract art.
just click on the applet to generate a new image
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Posted by Nikolaus Gradwohl
Thu, 05 Feb 2009 17:02:00 GMT
http://www.processing.org/ the mother of all processing sites :-)
http://www.arduino.cc/ a language and a microcontroller board that that go very well with
processing
http://mobile.processing.org/ a mobile phone edition of porcessing
http://www.openvisuals.org/ a site showing how to visualize data using processing
http://www.openprocessing.org/ a site collection processing sketches
http://www.processingblogs.org/ a processing meta blog
http://www.rmx.cz/monsters/ a collection of black'n'white monsters - coded in processing (one of them has been written by me :-) )
http://www.local-guru.net/blog/tag/processing my own site
two really great art collections using processing
http://www.complexification.net/gallery/
http://abandonedart.org/
some artists using processing
http://www.flight404.com/blog/?cat=1
http://www.toxi.co.uk/
http://www.benfry.com/
http://www.groupc.net/
Books:
make things talk
visualizing data
Processing: A Programming Handbook for Visual Designers and Artists
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Posted by Nikolaus Gradwohl
Thu, 05 Feb 2009 03:52:32 GMT
A while ago, a hook on our bathroom door fell down. First we thought it was because
of some loose screws. but today i found out the real reason - there
was a monster lurking behind it!
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