Assembly Language Tutorial
Assembly is a general name used for many human-readable forms of machine code. It naturally differs a lot between different CPUs (Central Processing Unit), but also on single CPU there may exist several incompatible dialects of Assembly, each compiled by different assembler, into the identical machine code defined by the CPU creator.
If you want to ask question about your own Assembly problem, always state what HW and which assembler you are using, otherwise it will be difficult to answer your question in detail.
Learning Assembly of single particular CPU will help to learn basics on different CPU, but every HW architecture can have considerable differences in details, so learning ASM for new platform can be close to learning it from scratch.