# Introduction

### By Bob Taylor and Thomas Defoe, 1992.

#### Electronic version by David Cantrell, 1994.
HTML-ized 1996/97.

Fortunately, when Amstrad developed the CPC and CPC+ computers, they let the user access many of the computer's internal routines (the firmware) and use them in their own programs. Experienced coders will no doubt write faster or more versatile code, yet these can easily be patched in using the Firmware Jumpblock.

For many years, Amstrad produced the definitive guide to the insides of the CPC but sale of this was stopped in 1989. Since then the Firmware Manual has been a much sought-after item by programmers. Nevertheless, the original guide had some omissions, notably the abscence of information on the system variables and the Z80 microprocessor inside every CPC and CPC+.

This guide is not intended to explain how to program in machine code, but we hope that it will supply the information needed to make the most of the Amstrad's capabilities when writing your own programs.

#### Bob Taylor and Thomas Defoe, 1992

Unfortunately, if you're using Netscape Navigator 4 you may experience problems. It does not implement style-sheets at all well. I would recommend using Microsoft Internet Explorer 4 - and after that piece of blasphemy I'll go and wash my mouth out.