\fcolorbox{black}{white}{%
	\setlength{\tabcolsep}{.2em}%
	\begin{tabular}{lcccccc}
		\multicolumn{7}{c}{\textbf{Function Calls}}\\\hline
		Arguments:    & rdi & rsi & rdx & rcx & r8 & r9\\
									& hp  & asp & A1  & A0  & A2 & scr\\
		\hline
		Result:       & rax & rdx \\
									& B0  & A1 \\
		\hline
		Callee-saved: & rbx & rbp & r12 & r13 & r14 & r15 \\
									& B1  & scr & B4  & B5  & B6  & free \\
	\end{tabular}%
}%