(ebook - english) anization and Design - The Hardware-Software Interface - Appendix A.pdf

A
APPENDIX
Assemblers,
Linkers,
and the SPIM
Simulator
James R. Larus
Computer Sciences Department
University of Wisconsin–Madison
Fear of serious injury cannot alone
justify suppression of free speech
and assembly.
Louis Brandeis
Whitney v. California, 1927
Introduction A-3
Assemblers A-10
Linkers A-17
Loading A-19
Memory Usage A-20
Procedure Call Convention A-22
Exceptions and Interrupts A-32
Input and Output A-36
SPIM A-38
MIPS R2000 Assembly Language A-49
Concluding Remarks A-75
Key Terms A-76
Exercises A-76
Introduction
Encoding instructions as binary numbers is natural and efficient put-
ers. Humans, however, have a great deal of difficulty understanding and
manipulating these numbers. People read and write symbols (words) much
better than long sequences of digits. Chapter 3 showed that we need not
choose between numbers and words puter instructions can be
represented in many ways. Humans can write and read symbols, -
puters can execute the equivalent binary numbers. This appendix describes
the process by which a human-readable program is translated into a form that
puter can execute, provides a few hints about writing assembly pro-
grams, and explains how to run these programs on SPIM, a simulator that
executes MIPS programs. Unix, Windows, and DOS versions of the SPIM sim-
ulator are available through .
Assembly language is the symbolic representation of puter’s binary en-
coding—machine language. Assembly language is more readable than machine
language because it uses symbols instead of bits. The symbols in assembly lan-
guage monly occurring bit patterns, such as opcodes and register
specifiers, so people can read and remember them. In addition, assembly lan-
guage permits programmers to use labels to identify and name particular
memory words that hold instructions or data.
A-4 Appendix A Assemblers, Link