Right CPU is determined by file name extension, or by .engine directive. Supported file name extensions are:
Intel 8080: .A80
Intel 8008: .A08
Zilog Z80: .Z80
Motorola 6800: .A68
Motorola 6809 / Hitachi HD6309: .A09
MOS 6502: .A65
WDC 65816: .816
CDP 1802: .A18