Asmc Macro Assembler Reference
.MODEL memorymodel [[, langtype]] [[, stackoption]]
Initializes the program memory model. The memorymodel can be TINY, SMALL, COMPACT, MEDIUM, LARGE, HUGE, or FLAT. The langtype can be C, BASIC, FORTRAN, PASCAL, SYSCALL, STDCALL, FASTCALL, or VECTORCALL. The stackoption can be NEARSTACK or FARSTACK.
Note: In 64-bit SYSCALL is also an instruction.