First get the [[Media:CPC_ROMs_for_MAME.zip|CPC ROMs for MAME]] and unzip them into the MAME roms folder.
Typical command line to start MAME in CPC mode(windowed mode and with a disc inserted in drive A): mame cpc6128 -skip_gameinfo -window -flop1 /path/to/disk.dsk
Supported CPC models are cpc464, cpc464p, cpc664, cpc6128, cpc6128p, gx4000, cpc6128f (French), cpc6128s (Swedish), and the clones kccomp ([[KC Compact]]) and al520ex ([[Aleste 520EX]]; hold Shift during boot to go to Basic).