Did you find the quick reference cards on ARMs website?

Also, the datasheets of actual chips usually contain information on the architecture (programmers model, etc).



Err .. no. ARM assembly isn't more complicated than '51 assembly. It's probably even less complicated, since you don't have to deal with almost half a dozen different memory types and the ways of accessing them, etc.

The only thing that might be a bit confusing at first is the conditional execution feature, i.e. that (almost, I don't remember) every instructions execution can be controlled by various CPU flags.