Editing Locomotive BASIC (section)

=== Firmware jump blocks ===
At a machine level on the CPC platform, application software need not be concerned with code moving about in the actual firmware (e.g. for different versions and re-assembly) so long as it uses the documented jump block addresses. For example, the firmware call TXT_PRINT_CHAR is ubiquitous - but note from below the firmware vectors are different in BASIC 1.0 and BASIC 1.1 ($9400 vs $93FE). In many machines, re-assemblies of the firmware and subsequent moving of routines can cause major headaches, but with the CPC platform so long as software uses the published jump block calls (i.e. $BB5A), software will run on all CPC platforms with no issues.
 
[[File:B1.0 BB5A.png|450px|frameless|center|$BB5A call on basic 1.0]]

The firmware jumps have changed between versions but the address for TXT_PRINT_CHAR remains $BB5A.

[[File:B1.1 BB5A.png|450px|frameless|center|$BB5A call on basic 1.1]]