diff --git a/FORTH.ASM b/FORTH.ASM
new file mode 100644
index 0000000..26576b5
--- /dev/null
+++ b/FORTH.ASM
@@ -0,0 +1,288 @@
+	;; FORTH.ASM -- Forth system for Microsoft (R) DOS
+
+	BITS 16
+
+	;; DOS loads .COM executables here
+	ORG 100h
+
+	%INCLUDE "DOS.ASM"
+	
+;;; MACROS ;;;
+
+	;; Step indirect threaded code to next word. Call this in a raw
+	;; word to effectively return. In an interpreted word SI first
+	;; needs to be reset to the calling value.
+	%MACRO NEXT 0
+	LODSW
+	MOV BX, AX						; [ax] is invalid in 16 bits
+	JMP [BX]
+	%ENDMACRO
+
+
+	;; Push register operand to return stack
+	%MACRO RSPUSH 1
+	SUB BP, WORDSZ
+	MOV [BP], %1
+	%ENDMACRO
+
+
+	;; Pop from return stack to register operand
+	%MACRO RSPOP 1
+	MOV %1, [BP]
+	ADD BP, WORDSZ
+	%ENDMACRO
+
+
+	;; Used for the compile-time dictionary linked list. Not used at
+	;; runtime.
+	%DEFINE LINK 0
+
+
+	IMMEDIATE_BIT EQU 1 << 6
+	HIDDEN_BIT EQU 1 << 5
+	LENGTH_MASK EQU 0b11111
+
+
+	;; Define a threaded word. The arguments should be the symbol for
+	;; the word, followed by the string version. e.g.:
+	;; 
+	;; DEFWORD DUP, 'DUP', IMMEDIATE_BIT
+	%MACRO DEFWORD 3
+	ALIGN 2
+
+WORD_%1:
+	DW LINK
+	%DEFINE LINK WORD_%1
+	DB WORDLEN_%1 | %3			; Length | Flags
+
+NAME_%1:
+	DB %2,
+	WORDLEN_%1 EQU $ - NAME_%1
+
+	ALIGN 2
+	
+%1:
+	%ENDMACRO
+
+
+	%MACRO DEFWORD_THREADED 2
+	DEFWORD %1, %2, 0
+	DW DOCOL
+	%ENDMACRO
+
+
+	%MACRO DEFWORD_THREADED_IMMED 2
+	DEFWORD %1, %2, IMMEDIATE_BIT
+	DW DOCOL
+	%ENDMACRO
+
+
+	;; Same as DEFWORD_THREADED but this time with raw code
+	%MACRO DEFWORD_RAW 2
+	DEFWORD %1, %2, 0
+	DW INTRAW					; Raw interpreter codeword
+
+	;; Callable from assembly
+CODE_%1:
+	%ENDMACRO
+
+
+	%MACRO DEFWORD_RAW_IMMEDIATE 2
+	DEFWORD %1, %2, IMMEDIATE_BIT
+	DW INTRAW
+
+	;; Callable from assembly
+CODE_%1:
+	%ENDMACRO
+
+
+	;; DEFVAR name, 'name'
+	;; dw 0
+	%MACRO DEFVAR 2
+	DEFWORD_RAW %1, %2
+	PUSH VAR_%1
+	NEXT
+
+VAR_%1:
+	%ENDMACRO
+
+	%MACRO DEFCONST 3
+	DEFWORD_RAW %1, %2
+	PUSH CONST_%1
+	NEXT
+	CONST_%1 EQU %3
+	%ENDMACRO
+
+
+	%MACRO INCLUDE_STRING 2
+	DW LITSTRING
+	DW STRINGLEN_%1
+.BEFORE_STRING_%1:
+	DB %2
+	STRINGLEN_%1 EQU $ - .BEFORE_STRING_%1
+	ALIGN WORDSZ
+	%ENDMACRO
+
+
+	;; TODO: This doesn't work for some reason
+	%MACRO RELATIVE_ADDRESS 1
+	DW (%1 - $)
+	%ENDMACRO
+
+
+;;; PROGRAM CODE ;;;
+
+_START:
+	;; Progran begins
+	MOV BP, SP
+	SUB BP, 1024				; why can't I use SP as a base for
+								; load effective address?
+	MOV SI, INDIRECT_START
+	NEXT
+
+	ALIGN 2
+
+
+	;; DO COLon definition -- Codeword for indirect threaded code
+	;; ax: indirect execution address
+DOCOL:	
+	RSPUSH si
+	ADD AX, WORDSZ				; Point to the first word address
+	MOV SI, AX					; Enter the function body (set si)
+	NEXT
+
+
+	;; Interpret raw code (plain machine code)
+INTRAW:
+	ADD AX, WORDSZ
+	JMP AX
+
+
+INDIRECT_START:	
+	DW SETUP 
+	DW QUIT
+	DW BYE
+
+
+SETUP:
+	DW INTRAW
+
+	MOV DX, MSG
+	WRITESOUT
+
+	NEXT
+
+LITERAL:
+	DW INTRAW
+
+	LODSW						; Load the next word
+	PUSH AX
+
+	NEXT
+
+
+EXIT:
+	DW INTRAW
+	RSPOP SI
+	NEXT
+
+TEST_PRINTING:
+	DW INTRAW
+	MOV AX, 5723
+	JMP DOT_INT
+	
+
+	DEFWORD_RAW BYE, 'BYE'
+	FLUSH
+	QUIT_PROC
+
+
+	DEFWORD_RAW LIT, 'LIT'
+	LODSW 						; Read next word from input to AX
+	PUSH AX
+	NEXT
+
+
+	DEFWORD_RAW DROP, 'DROP'
+	ADD SP, WORDSZ
+	NEXT
+
+
+	DEFWORD_RAW SWAP, 'SWAP'
+	POP AX
+	POP BX
+	PUSH AX
+	PUSH BX
+	NEXT
+
+
+	DEFWORD_RAW DUP, 'DUP'
+	;; This is stupid, [SP] is invalid
+	POP AX
+	PUSH AX
+	PUSH AX
+	NEXT
+
+
+	DEFWORD_RAW PLUS, '+'
+	POP AX
+	POP BX
+	ADD AX, BX
+	PUSH AX
+	NEXT
+
+
+	DEFWORD_RAW MINUS, '-'		; ( DX AX -- DX-AX )
+	POP AX
+	POP DX
+	SUB DX, AX
+	PUSH DX
+	NEXT
+
+
+	DEFWORD_RAW ADD1, '1+'
+	POP AX
+	ADD AX, 1
+	PUSH AX
+	NEXT
+
+
+	DEFWORD_RAW ADD2, '2+'
+	POP AX
+	ADD AX, 2
+	PUSH AX
+	NEXT
+
+
+	;; This kind of sucks
+	DEFWORD_RAW _2DUP, '2DUP'	; ( a b -- a b a b )
+	POP AX
+	POP BX
+	PUSH BX
+	PUSH AX
+	PUSH BX
+	PUSH AX
+	NEXT
+	
+
+	%INCLUDE "IOWORDS.ASM"
+	%INCLUDE "DICTNRY.ASM"
+	
+;;; LATE-INIT VARIABLES ;;;
+	DEFVAR STATE, 'STATE'
+	DW 0						; Interpret
+	
+	DEFVAR HERE, 'HERE'
+	DW HERE_START
+	
+	;; LATEST must be the last word defined in FORTH.ASM!
+	DEFVAR LATEST, 'LATEST'
+	DW LINK
+	
+
+;;; PROGRAM DATA ;;;
+	MSG DB 'DOS FORTH', 0Dh, 0Ah, '$'
+
+
+;;; FREE DATA ;;;
+HERE_START: