I understand how a computer works on the basic principles, such as, a program can be written in a "high" level language like C#, C and then it's broken down in to object code and then binary for the processor to understand. However, I really want to learn about assembly, and how it's used in modern day applications.
I know processors have different instruction sets above the basic x86 instruction set. Do all assembly languages support all instruction sets?
How many assembly languages are there? How many work well with other languages?
How would someone go about writing a routine in assembly, and then compiling it in to object/binary code?
How would someone then reference the functions/routines within that assembly code from a language like C or C++?
How do we know the code we've written in assembly is the fastest it possibly can be?
Are there any recommended books on assembly languages/using them with modern programs?
Sorry for the quantity of questions, I do hope they're general enough to be useful for other people as well as simple enough for others to answer!