\documentclass[11pt]{letter}
\usepackage[margin=2cm]{geometry}
\geometry{a4paper}
%\usepackage[parfill]{parskip}    % Activate to begin paragraphs with an empty line rather than an indent
\usepackage{graphicx}
\usepackage{amssymb}
\usepackage{epstopdf}
\usepackage{bytefield}
\usepackage{xcolor}

% facilitates the creation of memory maps. Start address at the bottom, end address at the top.
% syntax: \memsection{end address}{start address}{height in lines}{text in box}
\newcommand{\memsection}[4]{
\bytefieldsetup{bitheight=#3\baselineskip}    % define the height of the memsection
\bitbox[]{10}{
\texttt{#1}     % print end address
\\ \vspace{#3\baselineskip} \vspace{-2\baselineskip} \vspace{-#3pt} % do some spacing
\texttt{#2} % print start address
}
\bitbox{32}{#4} % print box with caption
}

\DeclareGraphicsRule{.tif}{png}{.png}{`convert #1 `dirname #1`/`basename #1 .tif`.png}

\title{\textsc{x86} Memory Map}

\begin{document}

\begin{bytefield}{32}	
	\memsection{ffff ffff}{f800 0000}{4}{-- reseved --}\\
		
	\begin{rightwordgroup}{Platform Specific}
		\memsection{f7ff ffff}{f400 0000}{3}{-- reseved --}\\
		\memsection{f3ff ffff}{f300 0000}{2}{Arch temp mappings}\\
		\memsection{f2ff ffff}{f200 0000}{2}{Temporary paging mapping area}\\
		\memsection{f1ff ffff}{f100 0000}{2}{MMIO (\textsc{apic}, \textsc{hpet}, etc.)}\\
		\memsection{f0ff ffff}{f000 0000}{2}{ACPI Tables}
	\end{rightwordgroup}\\
	
	\memsection{dfff ffff}{c800 0000}{10}{Anonymous memory pool}\\
	
	\memsection{c7ff ffff}{c300 0000}{4}{-- reseved --}\\
	
	\memsection{c2ff ffff}{c100 0000}{3}{Kernel stacks\\1024x 32K stacks} \\
	
	\memsection{c0ff ffff}{c060 0000}{2}{-- reseved --}\\
	\memsection{c05f ffff}{c040 0000}{2}{Physical memory alloc bitmaps} \\
	
	\memsection{c03f ffff}{c010 0000}{2}{Kernel \texttt{.text}/\texttt{.data}} \\
	\memsection{c00f ffff}{c000 0000}{2}{-- reseved --}\\
	
	%%%
	\memsection{bfff ffff}{bf60 0000}{3}{Page table self map area}\\

	\memsection{bf5f ffff}{bf00 0000}{2}{-- reseved --}\\
	\memsection{beff ffff}{0000 0000}{6}{\it User Space}\\
\end{bytefield}

All sections marked as reserved are currently not mapped.

\end{document}  