diff --git a/src/popupmenu.c b/src/popupmenu.c
new file mode 100644
index 0000000..26c4ae7
--- /dev/null
+++ b/src/popupmenu.c
@@ -0,0 +1,301 @@
+/* vi:set ts=8 sts=4 sw=4:
+ *
+ * VIM - Vi IMproved	by Bram Moolenaar
+ *
+ * Do ":help uganda"  in Vim to read copying and usage conditions.
+ * Do ":help credits" in Vim to see a list of people who contributed.
+ * See README.txt for an overview of the Vim source code.
+ */
+
+/*
+ * popupmenu.c: Popup menu (PUM)
+ */
+#include "vim.h"
+
+#if defined(FEAT_INS_EXPAND) || defined(PROTO)
+
+static char_u **pum_array = NULL;	/* items of displayed pum */
+static int pum_size;			/* nr of items in "pum_array" */
+static int pum_selected;		/* index of selected item or -1 */
+static int pum_first = 0;		/* index of top item */
+
+static int pum_height;			/* nr of displayed pum items */
+static int pum_width;			/* width of displayed pum items */
+static int pum_scrollbar;		/* TRUE when scrollbar present */
+
+static int pum_row;			/* top row of pum */
+static int pum_col;			/* left column of pum */
+
+#define PUM_DEF_HEIGHT 10
+#define PUM_DEF_WIDTH  15
+
+/*
+ * Show the popup menu with items "array[size]".
+ * "array" must remain valid until pum_undisplay() is called!
+ * When possible the leftmost character is aligned with screen column "col".
+ * The menu appears above the screen line "row" or at "row" + "height" - 1.
+ */
+    void
+pum_display(array, size, selected, row, height, col)
+    char_u	**array;
+    int		size;
+    int		selected;	/* index of initially selected item */
+    int		row;
+    int		height;
+    int		col;
+{
+    int		w;
+    int		def_width = PUM_DEF_WIDTH;
+    int		max_width = 0;
+    int		i;
+
+    /*
+     * Figure out the size and position of the pum.
+     */
+    if (size < PUM_DEF_HEIGHT)
+	pum_height = size;
+    else
+	pum_height = PUM_DEF_HEIGHT;
+
+    /* Put the pum below "row" if possible.  If there are few lines decide on
+     * where there is more room. */
+    if (row >= cmdline_row - pum_height && row > (cmdline_row - height) / 2)
+    {
+	/* pum above "row" */
+	if (row >= size)
+	{
+	    pum_row = row - size;
+	    pum_height = size;
+	}
+	else
+	{
+	    pum_row = 0;
+	    pum_height = row;
+	}
+    }
+    else
+    {
+	/* pum below "row" */
+	pum_row = row + height;
+	if (size > cmdline_row - pum_row)
+	    pum_height = cmdline_row - pum_row;
+	else
+	    pum_height = size;
+    }
+
+    /* don't display when we only have room for one line */
+    if (pum_height <= 1)
+	return;
+
+    /* Compute the width of the widest match. */
+    for (i = 0; i < size; ++i)
+    {
+	w = vim_strsize(array[i]);
+	if (max_width < w)
+	    max_width = w;
+    }
+
+    /* if there are more items than room we need a scrollbar */
+    if (pum_height < size)
+    {
+	pum_scrollbar = 1;
+	++max_width;
+    }
+    else
+	pum_scrollbar = 0;
+
+    if (def_width < max_width)
+	def_width = max_width;
+
+    if (col < Columns - PUM_DEF_WIDTH || col < Columns - max_width)
+    {
+	/* align pum column with "col" */
+	pum_col = col;
+	pum_width = Columns - pum_col - pum_scrollbar;
+	if (pum_width > def_width)
+	    pum_width = def_width;
+    }
+    else if (Columns < def_width)
+    {
+	/* not enough room, will use what we have */
+	pum_col = 0;
+	pum_width = Columns - 1;
+    }
+    else
+    {
+	if (max_width > PUM_DEF_WIDTH)
+	    max_width = PUM_DEF_WIDTH;	/* truncate */
+	pum_col = Columns - max_width;
+	pum_width = max_width - pum_scrollbar;
+    }
+
+    pum_array = array;
+    pum_size = size;
+
+    /* Set selected item and redraw. */
+    pum_set_selected(selected);
+}
+
+/*
+ * Redraw the popup menu, using "pum_first" and "pum_selected".
+ */
+    void
+pum_redraw()
+{
+    int		row = pum_row;
+    int		col;
+    int		attr_norm = highlight_attr[HLF_PNI];
+    int		attr_select = highlight_attr[HLF_PSI];
+    int		attr_scroll = highlight_attr[HLF_PSB];
+    int		attr_thumb = highlight_attr[HLF_PST];
+    int		attr;
+    int		i;
+    int		idx;
+    char_u	*s;
+    char_u	*p;
+    int		width, w;
+    int		thumb_pos = 0;
+    int		thumb_heigth = 1;
+
+    if (pum_scrollbar)
+    {
+	thumb_heigth = pum_height * pum_height / pum_size;
+	if (thumb_heigth == 0)
+	    thumb_heigth = 1;
+	thumb_pos = (pum_first * (pum_height - thumb_heigth)
+			    + (pum_size - pum_height) / 2)
+						    / (pum_size - pum_height);
+    }
+
+    for (i = 0; i < pum_height; ++i)
+    {
+	idx = i + pum_first;
+	attr = (idx == pum_selected) ? attr_select : attr_norm;
+
+	/* prepend a space if there is room */
+	if (pum_col > 0)
+	    screen_putchar(' ', row, pum_col - 1, attr);
+
+	/* Display each entry, use two spaces for a Tab. */
+	col = pum_col;
+	width = 0;
+	s = NULL;
+	for (p = pum_array[idx]; ; mb_ptr_adv(p))
+	{
+	    if (s == NULL)
+		s = p;
+	    w = ptr2cells(p);
+	    if (*p == NUL || *p == TAB || width + w > pum_width)
+	    {
+		/* Display the text that fits or comes before a Tab. */
+		screen_puts_len(s, p - s, row, col, attr);
+		col += width;
+
+		if (*p != TAB)
+		    break;
+
+		/* Display two spaces for a Tab. */
+		screen_puts_len((char_u *)"  ", 2, row, col, attr);
+		col += 2;
+		s = NULL;
+		width = 0;
+	    }
+	    else
+		width += w;
+	}
+
+	screen_fill(row, row + 1, col, pum_col + pum_width, ' ', ' ', attr);
+	if (pum_scrollbar > 0)
+	    screen_putchar(' ', row, pum_col + pum_width,
+		    i >= thumb_pos && i < thumb_pos + thumb_heigth
+						  ? attr_thumb : attr_scroll);
+
+	++row;
+    }
+}
+
+#if 0 /* not used yet */
+/*
+ * Return the index of the currently selected item.
+ */
+    int
+pum_get_selected()
+{
+    return pum_selected;
+}
+#endif
+
+/*
+ * Set the index of the currently selected item.  The menu will scroll when
+ * necessary.
+ */
+    void
+pum_set_selected(n)
+    int	    n;
+{
+    pum_selected = n;
+
+    if (pum_selected >= 0)
+    {
+	if (pum_first > pum_selected)
+	    /* scroll down */
+	    pum_first = pum_selected;
+	else if (pum_first < pum_selected - pum_height + 1)
+	    /* scroll up */
+	    pum_first = pum_selected - pum_height + 1;
+
+	if (pum_height > 6)
+	{
+	    /* Give three lines of context when possible. */
+	    if (pum_first > pum_selected - 3)
+	    {
+		/* scroll down */
+		pum_first = pum_selected - 3;
+		if (pum_first < 0)
+		    pum_first = 0;
+	    }
+	    else if (pum_first < pum_selected + 3 - pum_height + 1)
+	    {
+		/* scroll up */
+		pum_first = pum_selected + 3 - pum_height + 1;
+	    }
+	}
+    }
+
+    /* Never display more than we have */
+    if (pum_first > pum_size - pum_height)
+	pum_first = pum_size - pum_height;
+
+    pum_redraw();
+}
+
+/*
+ * Undisplay the popup menu (later).
+ */
+    void
+pum_undisplay()
+{
+    pum_array = NULL;
+    redraw_all_later(NOT_VALID);
+}
+
+/*
+ * Clear the popup menu.  Currently only resets the offset to the first
+ * displayed item.
+ */
+    void
+pum_clear()
+{
+    pum_first = 0;
+}
+
+/*
+ * Return TRUE if the popup menu is displayed.
+ */
+    int
+pum_visible()
+{
+    return pum_array != NULL;
+}
+
+#endif