Use the following applet to simulate the working of a computer highlighting in detail the functions of CPU. Observe how a CPU really works and the interactions between the different components (like RAM, North Bridge, The i/o devices, CPU...) of the PC for the execution of assembly level programs.
Click for help on Assembly language of the pPC:
Click for some Sample Codes
For detailed description of how a PC works ( and in particular this PC works :-) ), go to
http://www.hardwaresecrets.com/article/209