diff --git a/atrcopy/__init__.py b/atrcopy/__init__.py
index b95ea17..cfcfd22 100644
--- a/atrcopy/__init__.py
+++ b/atrcopy/__init__.py
@@ -228,8 +228,13 @@ def assemble_segments(source_files, data_files, obj_files, run_addr=""):
             print(f"skipping {name}: {e}")
         else:
             for s in parser.segments:
-                if s.origin > 0:
-                    print("adding %s from %s" % (s, name))
+                if hasattr(s, 'run_address'):
+                    if not run_addr:
+                        run_addr = s.run_address()
+                    else:
+                        print(f"already have run address {run_addr}; skipping {s.run_address()}")
+                elif s.origin > 0:
+                    print(f"adding {s} from {name}")
                     segments.add_segment(s.data, s.origin)
     if options.verbose:
         for s in segments:
@@ -237,8 +242,12 @@ def assemble_segments(source_files, data_files, obj_files, run_addr=""):
     if run_addr:
         try:
             run_addr = text_to_int(run_addr)
-        except ValueError:
-            run_addr = None
+        except (AttributeError, ValueError):
+            # not text, try as integer
+            try:
+                run_addr = int(run_addr)
+            except ValueError:
+                run_addr = None
 
     return segments, run_addr
 
diff --git a/atrcopy/ataridos.py b/atrcopy/ataridos.py
index 99caa2f..06613b2 100644
--- a/atrcopy/ataridos.py
+++ b/atrcopy/ataridos.py
@@ -4,6 +4,7 @@ from . import errors
 from .diskimages import DiskImageBase, BaseHeader
 from .segments import SegmentData, EmptySegment, ObjSegment, RawSectorsSegment, DefaultSegment, SegmentedFileSegment, SegmentSaver, get_style_bits
 from .utils import *
+from .executables import get_xex
 
 import logging
 log = logging.getLogger(__name__)
@@ -256,6 +257,16 @@ class XexSegment(ObjSegment):
     savers = [SegmentSaver, XexSegmentSaver]
 
 
+class RunAddressSegment(ObjSegment):
+    # FIXME: defining run_address as a property doesn't work for some reason.
+    # @property
+    # def run_address(self):
+    #     return self.rawdata[0:2].view(dtype="<u2")[0]
+    def run_address(self):
+        return self.rawdata[0:2].data.view(dtype="<u2")[0]
+
+
+
 class AtariDosFile:
     """Parse a binary chunk into segments according to the Atari DOS object
     file format.
@@ -313,7 +324,12 @@ class AtariDosFile:
             if found < count:
                 self.segments.append(ObjSegment(r[pos + 4:pos + 4 + count], pos, pos + 4, start, end, "Incomplete Data"))
                 break
-            self.segments.append(ObjSegment(r[pos + 4:pos + 4 + count], pos, pos + 4, start, end))
+            if start == 0x2e0:
+                segment_cls = RunAddressSegment
+            else:
+                segment_cls = ObjSegment
+            print(start, end, segment_cls)
+            self.segments.append(segment_cls(r[pos + 4:pos + 4 + count], pos, pos + 4, start, end))
             pos += 4 + count
             style_pos = pos
 
@@ -744,56 +760,6 @@ class AtariDiskImage(BootDiskImage):
         return []
 
 
-def get_xex(segments, run_addr=None):
-    segments_copy = [s for s in segments]  # don't affect the original list!
-    main_segment = None
-    sub_segments = []
-    data_style = get_style_bits(data=True)
-    total = 2
-    runad = False
-    for s in segments:
-        total += 4 + len(s)
-        if s.origin == 0x2e0:
-            runad = True
-    if not runad:
-        words = np.empty([1], dtype='<u2')
-        if run_addr:
-            found = False
-            for s in segments:
-                if run_addr >= s.origin and run_addr < s.origin + len(s):
-                    found = True
-                    break
-            if not found:
-                raise errors.InvalidBinaryFile("Run address points outside data segments")
-        else:
-            run_addr = segments[0].origin
-        words[0] = run_addr
-        r = SegmentData(words.view(dtype=np.uint8))
-        s = DefaultSegment(r, 0x2e0)
-        segments_copy[0:0] = [s]
-        total += 6
-    bytes = np.zeros([total], dtype=np.uint8)
-    rawdata = SegmentData(bytes)
-    main_segment = DefaultSegment(rawdata)
-    main_segment.data[0:2] = 0xff  # FFFF header
-    main_segment.style[0:2] = data_style
-    i = 2
-    for s in segments_copy:
-        # create new sub-segment inside new main segment that duplicates the
-        # original segment's data/style
-        new_s = DefaultSegment(rawdata[i:i+4+len(s)], s.origin)
-        words = new_s.data[0:4].view(dtype='<u2')
-        words[0] = s.origin
-        words[1] = s.origin + len(s) - 1
-        new_s.style[0:4] = data_style
-        new_s.data[4:4+len(s)] = s[:]
-        new_s.style[4:4+len(s)] = s.style[:]
-        i += 4 + len(s)
-        new_s.copy_user_data(s, 4)
-        sub_segments.append(new_s)
-    return main_segment, sub_segments
-
-
 def add_atr_header(bytes):
     header = AtrHeader(create=True)
     header.check_size(len(bytes))
diff --git a/atrcopy/dos33.py b/atrcopy/dos33.py
index c99d328..9fba871 100644
--- a/atrcopy/dos33.py
+++ b/atrcopy/dos33.py
@@ -4,6 +4,7 @@ from . import errors
 from .diskimages import BaseHeader, DiskImageBase
 from .utils import Directory, VTOC, WriteableSector, BaseSectorList, Dirent
 from .segments import DefaultSegment, EmptySegment, ObjSegment, RawTrackSectorSegment, SegmentSaver, get_style_bits, SegmentData
+from .executables import get_bsave
 
 import logging
 log = logging.getLogger(__name__)
@@ -591,42 +592,8 @@ class Dos33DiskImage(DiskImageBase):
         return segment
 
     def create_executable_file_image(self, segments, run_addr=None):
-        # Apple 2 executables get executed at the first address loaded. If the
-        # run_addr is not the first byte of the combined data, have to create a
-        # new 3-byte segment with a "JMP run_addr" to go at the beginning
-        origin = 100000000
-        last = -1
-
-        for s in segments:
-            origin = min(origin, s.origin)
-            last = max(last, s.origin + len(s))
-            if _xd: log.debug("contiguous bytes needed: %04x - %04x" % (origin, last))
-        if run_addr and run_addr != origin:
-            # check if run_addr points to some location that has data
-            found = False
-            for s in segments:
-                if run_addr >= s.origin and run_addr < s.origin + len(s):
-                    found = True
-                    break
-            if not found:
-                raise errors.InvalidBinaryFile("Run address points outside data segments")
-            origin -= 3
-            hi, lo = divmod(run_addr, 256)
-            raw = SegmentData([0x4c, lo, hi])
-            all_segments = [DefaultSegment(raw, origin=origin)]
-            all_segments.extend(segments)
-        else:
-            all_segments = segments
-        size = last - origin
-        image = np.zeros([size + 4], dtype=np.uint8)
-        words = image[0:4].view(dtype="<u2")  # always little endian
-        words[0] = origin
-        words[1] = size
-        for s in all_segments:
-            index = s.origin - origin + 4
-            print("setting data for $%04x - $%04x at index $%04x" % (s.origin, s.origin + len(s), index))
-            image[index:index + len(s)] = s.data
-        return image, 'B'
+        data = get_bsave(segments, run_addr)
+        return data, 'B'
 
 
 class Dos33BinFile:
diff --git a/atrcopy/executables.py b/atrcopy/executables.py
new file mode 100644
index 0000000..d06f56f
--- /dev/null
+++ b/atrcopy/executables.py
@@ -0,0 +1,101 @@
+import numpy as np
+
+from . import errors
+from .diskimages import DiskImageBase, BaseHeader
+from .segments import SegmentData, EmptySegment, ObjSegment, RawSectorsSegment, DefaultSegment, SegmentedFileSegment, SegmentSaver, get_style_bits
+from .utils import *
+
+import logging
+log = logging.getLogger(__name__)
+try:  # Expensive debugging
+    _xd = _expensive_debugging
+except NameError:
+    _xd = False
+
+
+def get_xex(segments, run_addr=None):
+    segments_copy = [s for s in segments]  # don't affect the original list!
+    main_segment = None
+    sub_segments = []
+    data_style = get_style_bits(data=True)
+    total = 2
+    runad = False
+    for s in segments:
+        total += 4 + len(s)
+        if s.origin == 0x2e0:
+            runad = True
+    if not runad:
+        words = np.empty([1], dtype='<u2')
+        if run_addr:
+            found = False
+            for s in segments:
+                if run_addr >= s.origin and run_addr < s.origin + len(s):
+                    found = True
+                    break
+            if not found:
+                raise errors.InvalidBinaryFile("Run address points outside data segments")
+        else:
+            run_addr = segments[0].origin
+        words[0] = run_addr
+        r = SegmentData(words.view(dtype=np.uint8))
+        s = DefaultSegment(r, 0x2e0)
+        segments_copy[0:0] = [s]
+        total += 6
+    bytes = np.zeros([total], dtype=np.uint8)
+    rawdata = SegmentData(bytes)
+    main_segment = DefaultSegment(rawdata)
+    main_segment.data[0:2] = 0xff  # FFFF header
+    main_segment.style[0:2] = data_style
+    i = 2
+    for s in segments_copy:
+        # create new sub-segment inside new main segment that duplicates the
+        # original segment's data/style
+        new_s = DefaultSegment(rawdata[i:i+4+len(s)], s.origin)
+        words = new_s.data[0:4].view(dtype='<u2')
+        words[0] = s.origin
+        words[1] = s.origin + len(s) - 1
+        new_s.style[0:4] = data_style
+        new_s.data[4:4+len(s)] = s[:]
+        new_s.style[4:4+len(s)] = s.style[:]
+        i += 4 + len(s)
+        new_s.copy_user_data(s, 4)
+        sub_segments.append(new_s)
+    return main_segment, sub_segments
+
+def get_bsave(segments, run_addr=None):
+    # Apple 2 executables get executed at the first address loaded. If the
+    # run_addr is not the first byte of the combined data, have to create a
+    # new 3-byte segment with a "JMP run_addr" to go at the beginning
+    origin = 100000000
+    last = -1
+
+    for s in segments:
+        origin = min(origin, s.origin)
+        last = max(last, s.origin + len(s))
+        if _xd: log.debug("contiguous bytes needed: %04x - %04x" % (origin, last))
+    if run_addr and run_addr != origin:
+        # check if run_addr points to some location that has data
+        found = False
+        for s in segments:
+            if run_addr >= s.origin and run_addr < s.origin + len(s):
+                found = True
+                break
+        if not found:
+            raise errors.InvalidBinaryFile("Run address points outside data segments")
+        origin -= 3
+        hi, lo = divmod(run_addr, 256)
+        raw = SegmentData([0x4c, lo, hi])
+        all_segments = [DefaultSegment(raw, origin=origin)]
+        all_segments.extend(segments)
+    else:
+        all_segments = segments
+    size = last - origin
+    image = np.zeros([size + 4], dtype=np.uint8)
+    words = image[0:4].view(dtype="<u2")  # always little endian
+    words[0] = origin
+    words[1] = size
+    for s in all_segments:
+        index = s.origin - origin + 4
+        print("setting data for $%04x - $%04x at index $%04x" % (s.origin, s.origin + len(s), index))
+        image[index:index + len(s)] = s.data
+    return image