diff --git a/.gitignore b/.gitignore
index 232d630..42f1837 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 *.html
 *.COM
 *.exe
+*.pdf
diff --git a/CORE.F b/CORE.F
index a965968..74aff9d 100644
--- a/CORE.F
+++ b/CORE.F
@@ -1,6 +1,32 @@
 \ Core words for DOS FORTH
 
 : NIP SWAP DROP ;
+: / /MOD NIP ;
+: MOD /MOD DROP ;
+
+: LITERAL IMMEDIATE ' LIT , , ;
+: [COMPILE] IMMEDIATE WORD FIND >CFA , ;
+: RECURSE IMMEDIATE LATEST , >CFA , ;
+
+\ Control structures
+
+\ cond IF <*b0> true ELSE false THEN rest
+: IF ( -- *then ) IMMEDIATE ' 0BRANCH , HERE @ 0 , ;
+
+: THEN ( *then -- *then ) IMMEDIATE
+  DUP HERE @ SWAP ( *then *then *here )
+  SWAP - ( *then *here-*then )
+  SWAP ! ;
+
+: ELSE ( *then -- *here ) IMMEDIATE
+  ' BRANCH ,
+  HERE @ ( *then *ph )
+  0 ,
+  SWAP ( *ph *then )
+  DUP ( *ph *then *then )
+  HERE @ ( *ph *then *then *here )
+  SWAP - ( *ph *then diff )
+  SWAP ! ( *ph ) ;
 
 DUMP-IMAGE FORTH.COM
 BYE
diff --git a/DICTNRY.ASM b/DICTNRY.ASM
index d180f8d..7a78fe8 100644
--- a/DICTNRY.ASM
+++ b/DICTNRY.ASM
@@ -85,6 +85,14 @@
 	NEXT
 
 
+	;; ( char address -- )
+	DEFWORD_RAW SETCHAR, 'C!'
+	POP BX
+	POP AX
+	MOV BYTE [BX], AL
+	NEXT
+
+
 	;; Code field address
 	DEFWORD_RAW CFA, '>CFA'
 	POP BX
@@ -128,6 +136,7 @@
 	NEXT
 
 
+	;; ( start length -- )
 	DEFWORD_RAW CMOVE_HERE, 'CMOVE,'
 	POP CX
 	RSPUSH SI
diff --git a/FORTH.ASM b/FORTH.ASM
index 8d8dc28..19c184f 100644
--- a/FORTH.ASM
+++ b/FORTH.ASM
@@ -186,11 +186,6 @@
 	RSPOP SI
 	NEXT
 
-TEST_PRINTING:
-	DW INTRAW
-	MOV AX, 5723
-	JMP DOT_INT
-	
 
 	DEFWORD_RAW BYE, 'BYE'
 	FLUSH
@@ -241,8 +236,8 @@
 
 
 	DEFWORD_RAW SLASHMOD, '/MOD'
-	POP DX
 	POP AX
+	POP DX
 	IDIV DX
 	PUSH DX						; Remainder
 	PUSH AX						; Quotient
diff --git a/IOWORDS.ASM b/IOWORDS.ASM
index b040458..cf3a726 100644
--- a/IOWORDS.ASM
+++ b/IOWORDS.ASM
@@ -207,7 +207,7 @@
 	RET
 
 
-	;; ( flags *start len )
+	;; ( flags *start len -- handle )
 	DEFWORD_RAW OPEN_FILE_NAMED, 'OPEN-FILE-NAMED'
 	POP CX						; Length
 	POP BX						; Start
diff --git a/doc/manual.tex b/doc/manual.tex
new file mode 100644
index 0000000..d5548aa
--- /dev/null
+++ b/doc/manual.tex
@@ -0,0 +1,296 @@
+\documentclass[letterpaper,11pt,twocolumn]{article}
+\usepackage[top=1in, bottom=1in, left=1in, right=1in]{geometry}\usepackage[T1]{fontenc}
+\usepackage[utf8]{inputenc}
+\usepackage{lmodern}
+\usepackage{amsmath}
+\usepackage{amsfonts}
+\usepackage{amssymb}
+\usepackage{amsthm}
+\usepackage{graphicx}
+\usepackage{color}
+\usepackage{xcolor}
+\usepackage{url}
+\usepackage{textcomp}
+\usepackage{listings}
+\usepackage{glossaries}
+\usepackage{parskip}
+\usepackage{imakeidx}
+\usepackage{hyperref}
+
+\makeindex
+
+\title{DOS Forth Manual}
+\author{}
+\date{}
+
+\newcommand{\defword}[3]{\textbf{#1}\index{#1}\label{word:#1} #2 (#3)\quad}
+\newcommand{\then}{\text{-- }}
+\newenvironment{expl}{$\triangleright$}{}
+\newcommand{\wordref}[1]{\textbf{#1} \ref{word:#1}}
+
+\begin{document}
+
+\maketitle
+\tableofcontents
+
+\section{Words}
+
+\subsection{Stack manipulation}
+
+\defword{swap}{}{a b \then b a}
+
+\defword{dup}{}{a \then a a}
+
+\defword{drop}{}{a \then}
+
+\defword{nip}{}{a b \then b}
+
+\defword{2dup}{}{a b \then a b a b}
+
+\subsection{Logic and arithmetic}
+
+\defword{+}{}{a b \then a+b}
+
+\defword{-}{}{a b \then a-b}
+
+\defword{*}{}{a b \then a$\times$b}
+
+\defword{/mod}{}{a b \then rem quot}
+\begin{expl}
+    Rem is the remainder, quot is the quotient of a/b.
+\end{expl}
+
+\defword{and}{}{a b \then a\&b}
+\begin{expl}
+    Bitwise and.
+\end{expl}
+
+\defword{xor}{}{a b \then a\^b}
+\begin{expl}
+    Bitwise exclusive or.
+\end{expl}
+
+\subsection{Input and output}
+
+\defword{key}{}{ \then char}
+\begin{expl}
+    Char is the next ASCII character from the input.
+\end{expl}
+
+\defword{word}{}{ \then address length}
+\begin{expl}
+    Reads the next whitespace-terminated word from the input. Address is the address of the first byte, length is the length in bytes. The maximum length is 32 bytes.
+    
+    Word uses a buffer which is reused every call. If you want the parsed string to persist after the next call you must copy it to your own buffer.
+\end{expl}
+
+\defword{number}{}{address length \then number unparsed}
+\begin{expl}
+    Parses the specified string as a base-10 number. Number is the parsed number as a cell, unparsed is the number of unparsed bytes, e.g. 0 if everything was parsed.
+\end{expl}
+
+\defword{.}{}{num \then}
+\begin{expl}
+    Writes number as a base-10 digit to the output.
+\end{expl}
+
+\defword{emit}{}{char \then}
+\begin{expl}
+    Writes the byte char to the output literally.
+\end{expl}
+
+\defword{cr}{}{ \then }
+\begin{expl}
+    Writes a carriate return followed by a newline to the output.
+\end{expl}
+
+\defword{space}{}{ \then }
+\begin{expl}
+    Writes an ASCII space to the output.
+\end{expl}
+
+\defword{type}{}{address length \then}
+\begin{expl}
+    Write the string of bytes starting at address of the specified length to the output. See also \wordref{word}.
+\end{expl}
+
+\defword{open-file-named}{}{flags address length \then handle}
+\begin{expl}
+    Opens the file specified by the string address and length with the given flags. \textit{TODO: document flags}. Handle is 0 if the file could not be opened.
+\end{expl}
+
+\defword{open-file}{name}{flags \then handle}
+\begin{expl}
+    Same as \wordref{open-file-named} but reads the name from the input at runtime.
+\end{expl}
+
+\defword{close-file}{}{handle \then}
+\begin{expl}
+    Closes the file specified by handle.
+\end{expl}
+
+\defword{f,}{}{cell handle \then}
+\begin{expl}
+    Writes cell (2 bytes) to the given file.
+\end{expl}
+
+\defword{fc,}{}{char handle \then}
+\begin{expl}
+    Writes the byte char to the given file.
+\end{expl}
+
+\defword{fwrite-range}{}{start-address end-address handle \then}
+\begin{expl}
+    Writes the memory range starting at start-address up to but not including end-address to the given file. 
+\end{expl}
+
+\subsection{Dictionary}
+
+\defword{find}{}{address length \then entry}
+\begin{expl}
+    Finds the dictionary entry with the name string specified by address and length in the dictionary. Entry is the address of the first byte of the dictionary entry. See also \wordref{>cfa}, \wordref{>dfa}. Entry is zero if a suitable entry cannot be found.
+\end{expl}
+
+\defword{@}{}{address \then value}
+\begin{expl}
+    Gets the cell starting at address from memory.
+\end{expl}
+
+\defword{!}{}{value address \then}
+\begin{expl}
+    Sets the cell at address to value.
+\end{expl}
+
+\defword{c@}{}{address \then char}
+\begin{expl}
+    Gets the byte at address from memory.
+\end{expl}
+
+\defword{c!}{}{char address \then}
+\begin{expl}
+    Sets the byte at address to char.
+\end{expl}
+
+\defword{>cfa}{}{entry \then cfa}
+\begin{expl}
+    Gets the code field address for the given dictionary entry.
+\end{expl}
+
+\defword{>dfa}{}{entry \then cfa}
+\begin{expl}
+    Gets the data field address for the given dictionary entry.
+\end{expl}
+
+\defword{cmove}{}{from to length \then}
+\begin{expl}
+    Copy the string of bytes length long starting at from to to. 
+\end{expl}
+
+\defword{round-even}{}{number \then even}
+\begin{expl}
+    Rounds number up until it is even. If it is already even returns it as is.
+\end{expl}
+
+\defword{cmove,}{}{from length \then}
+\begin{expl}
+    Moves the string of bytes length long starting at from to the top of the dictionary and offsets the here pointer.
+\end{expl}
+
+\defword{create}{name}{ \then}
+\begin{expl}
+    Creates a dictionary entry. Name is read from the input at runtime. 
+\end{expl}
+
+\defword{,}{}{value \then}
+\begin{expl}
+    Writes the cell value to the top of the stack, adding 2 to the here pointer.
+\end{expl}
+
+\defword{c,}{}{char \then}
+\begin{expl}
+    Writes the byte char to the top of the stack, adding 1 to the here pointer.
+\end{expl}
+
+\defword{[}{}{ \then}
+\begin{expl}
+    Switches to interpret mode.
+\end{expl}
+
+\defword{]}{}{ \then}
+\begin{expl}
+    Immediately switches to compile mode.
+\end{expl}
+
+\defword{immediate}{}{ \then}
+\begin{expl}
+    Immediately toggles if the most recently defined dictionary word is immediate.
+\end{expl}
+
+\defword{hidden}{}{ \then}
+\begin{expl}
+    Toggles if the most recently defined dictionary word is hidden.
+\end{expl}
+
+\defword{hide}{name}{ \then}
+\begin{expl}
+    Reads a word from the input at runtime, looks it up in the dictionary, and toggles if it is hidden.
+\end{expl}
+
+\defword{tick}{name}{ \then cfa}
+\begin{expl}
+    Reads a word from the input at runtime, looks it up in the dictionary, and returns its code field address.
+\end{expl}
+
+\defword{word-type}{}{entry \then type}
+\begin{expl}
+    Returns the type of the word starting at entry. 0 if immediate, 1 if normal.
+\end{expl}
+
+\defword{interpret}{name}{ \then ?}
+\begin{expl}
+    Reads a word from the input at runtime and interprets it.
+\end{expl}
+
+\defword{quit}{}{ \then ?}
+\begin{expl}
+    Runs \wordref{interpret} repeatedly.
+\end{expl}
+
+\defword{:}{name}{ \then }
+\begin{expl}
+    Begins defining a word with the specified name. Switches to compiling state.
+\end{expl}
+
+\defword{;}{}{ \then }
+\begin{expl}
+    Finishes defining a word. Switches back to interpreting state.
+\end{expl}
+
+\defword{entry->name}{}{entry \then address length}
+\begin{expl}
+    Finds the name of the dictionary entry starting at entry.
+\end{expl}
+
+\defword{words}{}{ \then }
+\begin{expl}
+    Writes a list of the currently defined non-hidden words to the output.
+\end{expl}
+
+\defword{.s}{}{ \then }
+\begin{expl}
+    Displays the current content of the stack from bottom to top.
+\end{expl}
+
+\subsection{Images and executables}
+
+\defword{dump-image}{name}{ \then }
+\begin{expl}
+    Dumps the current Forth image in .COM format to the file with the specified name. This saves the entire contents of the dictionary, but not the stack.
+\end{expl}
+
+\section{License}
+
+Copyright \copyright{} 2022 \href{https://swisschili.sh}{swissChili}. This document is released under the terms of the \href{https://www.gnu.org/licenses/fdl-1.3.html}{GNU Free Documentation License}.
+
+\printindex
+\end{document}
\ No newline at end of file
diff --git a/fth-mode.el b/fth-mode.el
new file mode 100644
index 0000000..6ad47d5
--- /dev/null
+++ b/fth-mode.el
@@ -0,0 +1,30 @@
+(defvar fth-mode-hook nil)
+
+(defvar fth-mode-map
+  (make-keymap)
+  "fth-mode keymap.")
+
+;;;#autoload
+(add-to-list 'auto-mode-alist '("\\.f" . fth-mode))
+
+(defconst fth-font-lock-keywords-1
+  (list (regexp-opt (cons '("if" ":" ";" "then" "loop" "do" "?do" "while" "until" "begin") 'font-lock-builtin-face)))
+  "Highlighting for fth-mode.")
+
+(defvar fth-mode-syntax-table
+  (let (st (make-syntax-table))
+    (modify-syntax-entry ?_ "w" st)
+    (modify-syntax-entry ?- "w" st)))
+
+(defun fth-mode ()
+  "Major mode for editing Forth code."
+  (interactive)
+  (kill-all-local-variables)
+  (set-syntax-table fth-mode-syntax-table)
+  (use-local-map fth-mode-map)
+  (set (make-local-variable 'font-lock-defaults) '(fth-font-lock-keywords-1))
+  (setq major-mode 'fth-mode)
+  (setq mode-name "4th")
+  (run-hooks 'fth-mode-hook))
+
+(provide 'fth-mode)