This section describes in detail the entry and exit conditions and the effects of all the routines in the main firmware jumpblock. The main firmware jumpblock is described in The Main Jumpblock.
The user is advised to read the sections on each pack before attempting to understand the jumpblock entries. The relevant sections are:
| Key Manager | (KM) | The Keyboard |
| Text VDU | (TXT) | The Text VDU |
| Graphics VDU | (GRA) | The Graphics VDU |
| Screen Pack | (SCR) | The Screen Pack |
| Sound Manager | (SOUND) | The Sound Manager |
| Cassette Manager | (CAS) | The Cassette Manager |
| AMSDOS | AMSDOS | |
| Kernel | (KL) | ROMs, RAM and the Restart Instructions, Expansion ROMs, Resident System Extensions and RAM Programs, Interrupts and Events |
| Machine Pack | (MC) | The Machine Pack |
Each description starts with the following layout:
Entries in the jumpblock are numbered starting from zero. The entry address is the address to call to invoke the firmware routine or the address of the three bytes to patch to intercept the routine. The entry address can be calculated as:
Entry address = Start of jumpblock + 3 * Entry number
Each entry is named and is refered to by name throughout this manual.
The last section of each description is a list of related routines. The user is advised to look at these as the list may include routines as the list may include routines more suited for the application being considered. Conversely the routines may shed further light on how the original routine should be used.
The descriptions of the routines are for the default routine that the entry jumps to. The user may change the entry and this may alter the action of the routine. The user is advised to stick to the entry/exit conditions described otherwise programs that call the routine (BASIC for example) may cease to operate correctly.