2. Introduction

Please Note

"Tiny Tim" was the title of the original project, from which Java Tiny Tim emerged. �Java Tiny Tim� was rewritten in Java (Tiny Tim was originally written in C), allowing enhancements that Tiny Tim would not. It is no way intended to be a first-step towards using Java specifically, only towards using modular languages and assembly.

You may occasionally see the term "Big Tim", which is the nickname for Java Tiny Tim. For simplicity, the original title (Java Tiny Tim, or "JTT") will be used in this Manual. For more information on Tiny Tim's background, see Chapter 8.

Java Tiny Tim (JTT) may be called a 'virtual machine'. Although it consists entirely of software, it aims at emulating the basic functions of a computer's processor. Its purpose is to develop an assembler package aimed at people wanting to learn low-level programming language concepts, i.e. where each instruction corresponds to only one processor instruction. It focuses on the principles of: Computer hardware and architecture concepts Low-level programming languages Operating systems Mathematical concepts � for example, boolean algebra It includes eight assembly instructions, a compiler and basic facilities s such as a command-line interface (CLI), 8 registers, interrupts and error management. JTT is aimed primarily at a general adult audience, especially computer science undergraduates at university, but also allows those with little or no experience in using assembler to easily develop skills in it. Some amount of experience in other programming languages, however, such as a BASIC, should be considered a significant benefit. It also allows the user to become familiar with modular programming languages, such as Java, by allowing programs to jump to other stored files as well as other parts of the instruction memory. Its special features include: A Graphical User Interface (GUI) front-end Loading and saving Memory management Pseudo-code and machinecode representations of code Extensive error-trapping and data recovery "JTT Beans" (JTTBs), which can be 'mail-merged' into JTT code A cut, copy and paste facility; A macro enabling the user to jump to JTT code within another file; An on-line help system. The error-trapping and recovery system involves a 'dumping' of JTT instruction and data memory and registers to a file before exiting (if possible), so that upon loading again the previous session is resumed automatically and without user prompting. The on-line help system is accessible via the CLI (using the 'h' command), given in straightforward text format, and the GUI (using the GUI's menu), in the form of a database. In the GUI's help system, the user can type in key words, and an index is created with a choice of appropriate help pages. The existing JTTBs provide a series of methods, written in JTT, are for use in: Providing examples with which the user can become familiar with JTT's operations Providing hands-on examples as extensions to the help provided on-line (i.e. within the GUI) and in the Manual Extending programs, or parts of programs without having to type out repeatedly more common functions (modularization) Promoting the modular aspect to most programming languages

Please Note

To avoid ambiguity, in the world of JTT the term 'instruction' is given to the eight operations of JTT's emulator (the instruction set), whilst the term 'command' is given to any of the operations used within JTT's CLI. The reader is reminded of the distinction throughout the Manual. For more information on the two terms, see Section 1.

Hosted by www.Geocities.ws