teaching  adv topic in digital systems 2015

2 march 2015

Nos  
how to explain the task switching.
talking about interrupt seems to be opague.
imagine interrupt occurs periodically and explain how Nos reacts to it.
how to separate high level and low level explanation.
especially, how not to have to go into assembly level of detail.

fix up the simulator
1)  build an interface
1.1   a window for peeking into processor 
1.2   a window to input machine code 
1.3   button single-step, run-to-breakpoint (how to set breakpoint)
1.4   button dump mem.
2)  simulator on javascript
2.1   get rid of graphic window
2.2   how to show output one charactor at a time

correct error on S2.3 instruction set explanation