Originally by Bob Taylor and Thomas Defoe, 1992
Electronic version scanned and formatted by David Cantrell, 1994

Computer programming is one of the most satisfying hobbies as it is a rare opportunity to invent, develop, and test your own ideas and see them come to fruition. Competent programming is a skill which is not easy to master, but once learnt, it will give hours of pleasure - there are many people who spend hours inventing new coding tricks, solving complex problems, or just trying out an idea.

Fortunately, when Amstrad developed the CPC and PLUS computers, they let the user access many of the computer's routines and use the Firmware in their own programs. Experienced programmers will no doubt write faster routines which are more efficient, or have some special feature, yet these extra facilities 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 almost 3 years ago. [Note - 3 yrs ago means 1989 here]. Since then the Firmware Manual has been regarded as an antique by those who are fortunate enough to own a copy. Nevertheless, the original guide had some omissions, notably the abscence of information on the system variables and the Z80 microprocessor inside every CPC or Plus.

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

• Firmware Memory usage
• Firmware jumpblocks
  • The Low Kernel Jumpblock
  • The High Kernel Jumpblock
  • The Key Manager
  • The Text VDU
  • The Graphics VDU
  • The Screen Pack
  • The Cassette/AmsDOS Manager
  • The Sound Manager
  • The Kernel
  • The Machine Pack
  • The Firmware Indirections
  • The Maths firmware
  • Maths routines for the 464 only
  • Subroutines for the 464 and 6128 only
  • AmsDOS and BIOS firmware