\documentclass[a4paper]{article}

\usepackage[english]{babel}
\usepackage[utf8x]{inputenc}
\usepackage[margin=1in]{geometry}

\usepackage{titlesec}
\usepackage{enumitem}
\titleformat{\section}{\large\scshape}{\thesection}{0em}{}
\titleformat{\subsection}{\normalfont\scshape}{\thesubsection}{0em}{}
\renewcommand*\thesection{Function \Roman{section}: }
\renewcommand*\thesubsection{Subroutine \Roman{section}.\Roman{subsection}: }

\newlist{subroutines}{enumerate}{1}
\setlist[subroutines]{label = Subroutine \Roman*:, leftmargin = 8em, labelsep = 0.5em, labelwidth = 7.5em, align = left}