diff --git a/merge-ort.c b/merge-ort.c
index 3325c9c0a2..d0abee9b6a 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -18,6 +18,7 @@
 #include "merge-ort.h"
 
 #include "strmap.h"
+#include "tree.h"
 
 struct merge_options_internal {
 	/*
@@ -164,6 +165,38 @@ struct conflict_info {
 	unsigned match_mask:3;
 };
 
+static int collect_merge_info(struct merge_options *opt,
+			      struct tree *merge_base,
+			      struct tree *side1,
+			      struct tree *side2)
+{
+	/* TODO: Implement this using traverse_trees() */
+	die("Not yet implemented.");
+}
+
+static int detect_and_process_renames(struct merge_options *opt,
+				      struct tree *merge_base,
+				      struct tree *side1,
+				      struct tree *side2)
+{
+	int clean = 1;
+
+	/*
+	 * Rename detection works by detecting file similarity.  Here we use
+	 * a really easy-to-implement scheme: files are similar IFF they have
+	 * the same filename.  Therefore, by this scheme, there are no renames.
+	 *
+	 * TODO: Actually implement a real rename detection scheme.
+	 */
+	return clean;
+}
+
+static void process_entries(struct merge_options *opt,
+			    struct object_id *result_oid)
+{
+	die("Not yet implemented.");
+}
+
 void merge_switch_to_result(struct merge_options *opt,
 			    struct tree *head,
 			    struct merge_result *result,
@@ -180,13 +213,46 @@ void merge_finalize(struct merge_options *opt,
 	die("Not yet implemented");
 }
 
+static void merge_start(struct merge_options *opt, struct merge_result *result)
+{
+	die("Not yet implemented.");
+}
+
+/*
+ * Originally from merge_trees_internal(); heavily adapted, though.
+ */
+static void merge_ort_nonrecursive_internal(struct merge_options *opt,
+					    struct tree *merge_base,
+					    struct tree *side1,
+					    struct tree *side2,
+					    struct merge_result *result)
+{
+	struct object_id working_tree_oid;
+
+	collect_merge_info(opt, merge_base, side1, side2);
+	result->clean = detect_and_process_renames(opt, merge_base,
+						   side1, side2);
+	process_entries(opt, &working_tree_oid);
+
+	/* Set return values */
+	result->tree = parse_tree_indirect(&working_tree_oid);
+	/* existence of conflicted entries implies unclean */
+	result->clean &= strmap_empty(&opt->priv->conflicted);
+	if (!opt->priv->call_depth) {
+		result->priv = opt->priv;
+		opt->priv = NULL;
+	}
+}
+
 void merge_incore_nonrecursive(struct merge_options *opt,
 			       struct tree *merge_base,
 			       struct tree *side1,
 			       struct tree *side2,
 			       struct merge_result *result)
 {
-	die("Not yet implemented");
+	assert(opt->ancestor != NULL);
+	merge_start(opt, result);
+	merge_ort_nonrecursive_internal(opt, merge_base, side1, side2, result);
 }
 
 void merge_incore_recursive(struct merge_options *opt,