Sections 3.1 - 3.3. Language Programming, written by Randall Hyde, Department of Computer Science and Engineering, University of California, Riverside. A provide a description of the MIPS architecture and instruction set. I would strongly recommend you to get hold of these and read them. This can execute MIPS assembly programs and provides a graphical interface.
User manuals are also available.
Language Programming , book provides a detailed description of the instruction set of the Intel microprocessors. This would give you insight of a different ISA specification and would enable you to compare it to MIPS and find similarities and differences. The book also discusses issues on boolean algebra, digital logic etc. The same with DEC VAX ISA description. Page created and maintained by Dr G. Theodoropoulos.