Code Optimization

General: 
Bit Twiddling Hacks: http://graphics.stanford.edu/~seander/bithacks.html
Five manuals on optimization(C++/ASM): http://www.agner.org/optimize/ 
Quick colour averaging: http://www.compuphase.com/graphic/scale3.htm
Quick image scaling by 2: http://www.compuphase.com/graphic/scale2.htm
Fixed Point Math: http://www.trenki.net/content/view/17/37/
Fixed Point Arithmetic - A Comprehensive Introduction:
http://forums.tigsource.com/index.php?topic=35880.0
https://stackoverflow.com/questions/10067510/fixed-point-arithmetic-in-c-programming
https://www.gamedev.net/forums/topic/214292-quick-explanationtutorial-on-fixed-point-math/
https://stackoverflow.com/a/80281
Fast Approximate Distance Functions: http://flipcode.com/archives/Fast_Approximate_Distance_Functions.shtml

AS3:
http://help.adobe.com/en_US/as3/mobile/flashplatform_optimizing_content.pdf
http://www.adobe.com/devnet/flash/articles/optimizing-flash-performance.html
http://osflash.org/as3_speed_optimizations
http://blog.joa-ebert.com/2008/04/26/actionscript-3-optimization-techniques/
http://wiki.joa-ebert.com/index.php/Category:Code_Optimization
http://www.accelermedia.com/node/55(some links there)
http://alexgblog.com/?p=392(lots of links there)
http://jacksondunstan.com (most blog posts are focus on AS3 optimization)
http://lab.polygonal.de/2007/05/10/bitwise-gems-fast-integer-math/
http://lab.polygonal.de/2007/07/18/fast-and-accurate-sinecosine-approximation/
http://blog.andre-michelle.com/2005/as3-optimations-suggestions/
http://gskinner.com/talks/quick/
http://gamedev.michaeljameswilliams.com/2010/02/10/optimise-as3-for-speed/
http://www.nbilyk.com/optimizing-actionscript-3
http://www.richnetapps.com/as3-performance-optimization/
http://hugolarcher.com/?p=42
http://blog.stanislavstankov.com/category/as3-optimization/
http://www.rozengain.com/blog/2007/05/01/some-actionscript-30-optimizations/
http://www.mikechambers.com/blog/2009/10/13/case-study-actionscript-3-performance-optimization/
http://www.calypso88.com/?cat=8
http://www.negush.net/blog/tag/as3-optimization/
http://upshots.org/actionscript/20-tips-to-optimize-your-actionscript
http://drawlogic.com/2009/05/22/as3-flash-efficient-code-techniques-vectors-in-flash-10-faster-jpeg-encoding-other-optimization-notes/

http://www.andymoore.ca/2012/01/how-to-improve-your-mobile-as3air-performance/
 
ActionScript ByteCode/Alchemy:
http://philippe.elsass.me/2010/05/as3-fast-memory-access-without-alchemy/
http://ncannasse.fr/blog/virtual_memory_api
http://code.google.com/p/apparat/
http://www.buraks.com/azoth/
http://forum.yogda.com/index.php?topic=15.0

ASM:
http://www.ibiblio.org/gferg/ldp/GCC-Inline-Assembly-HOWTO.html

C/C++:
http://www.codeproject.com/KB/cpp/C___Code_Optimization.aspx 
http://www.eventhelix.com/realtimemantra/basics/optimizingcandcppcode.htm
http://www.lri.fr/~bastoul/local_copies/lee.html

HaXe:
http://haxe.org/manual/macros
http://haxe.org/ref/inline
http://hxscout.com/(HaXe profiling tool)

Java: 
http://www.javaperformancetuning.com/tips/rawtips.shtml
http://appperfect.com/support/java-coding-rules/optimization.html
http://www.javacommerce.com/displaypage.jsp?name=java_performance.sql&id=18264