I have been trying to compile this program using tasm

.model tiny

mov ax,f000h


And I get this error

E:\zzzz1\lab>tasm test3.asm
Turbo Assembler Version 3.1 Copyright (c) 1988, 1992 Borland International

Assembling file: test3.asm
**Error** test3.asm(5) Undefined symbol: F000H
Error messages: 1
Warning messages: None
Passes: 1
Remaining memory: 459k

And another question is how do I halt the processor
I tried "hlt", but when the code runs it pops up a dialog which says illegal instruction.