Changes

Only 64K is directly accessible by the Z80. On the CPC architecture the last 16K is by default used as the screen data (addresses &C000 to &FFFF). Addresses 0 to &170 and HIMEM+1 to &BFFF is used by the Firmware, BASIC and AMSDOS ROM's. Himem is a Locomotive BASIC variable that reports the highest available free memory location when the CPC boots up. By lowering this value, you assign less space for the BASIC part of your program and it's its BASIC data (strings, variables, arrays). The rest (from the new HIMEM's value up to the initial HIMEM value when the computer boots up) can be used by your machine code and its data. You alter the HIMEM value by e.g.