diff --git a/8086/msdos/Makefile b/8086/msdos/Makefile
index 9a1a014..2c28424 100644
--- a/8086/msdos/Makefile
+++ b/8086/msdos/Makefile
@@ -2,14 +2,23 @@
 fbfiles = $(wildcard src/*.fb tests/*.fb)
 fthfiles = $(patsubst %.fb, %.fth, $(fbfiles))
 
+srcfbfiles = $(wildcard src/*.fb)
+srcfbtxtfiles = $(patsubst src/%.fb, src/%.fb.txt, $(srcfbfiles))
+testsfbfiles = $(wildcard tests/*.fb)
+testsfbtxtfiles = $(patsubst tests/%.fb, tests/%.fb.txt, $(testsfbfiles))
+fb_txt_files = $(srcfbtxtfiles) $(testsfbtxtfiles)
+
 test: incltest.result logtest.result test-std.result test-blk.result \
     incltest-volks4th.result test-volks4th-min.result test-stdi.result
 
 fth: $(fthfiles)
 
+fb.txt: $(fb_txt_files)
+
 clean:
 	rm -f *.log *.LOG *.result *.golden
 	rm -f dosfiles/*
+	rm -f tests/empty.fth tests/empty.fb.txt
 
 *.log: emulator/run-in-dosbox.sh
 
@@ -234,6 +243,17 @@ dosfiles/%: tests/% | dosfiles
 dosfiles:
 	mkdir $@
 
+$(srcfbtxtfiles): src/%.fb.txt: src/%.fb ../../tools/fb2fth.py
+	../../tools/fb2fth.py $< $@
+	mv $(patsubst %.fb, %.fth, $<) $(patsubst %.fb, %.fth.txt, $<) 
+	diff $(patsubst %.fb, %.fth.txt, $<) $(patsubst %.fb, %.fb.txt, $<) 
+
+$(testsfbtxtfiles): tests/%.fb.txt: tests/%.fb ../../tools/fb2fth.py
+	../../tools/fb2fth.py $< $@
+	mv $(patsubst %.fb, %.fth, $<) $(patsubst %.fb, %.fth.txt, $<) 
+	diff $(patsubst %.fb, %.fth.txt, $<) $(patsubst %.fb, %.fb.txt, $<) 
+
+
 src/%.fth: src/%.fb ../../tools/fb2fth.py
 	../../tools/fb2fth.py $< $@
 
diff --git a/8086/msdos/src/asm.fth b/8086/msdos/src/asm.fb.txt
similarity index 100%
rename from 8086/msdos/src/asm.fth
rename to 8086/msdos/src/asm.fb.txt
diff --git a/8086/msdos/src/blocking.fth b/8086/msdos/src/blocking.fb.txt
similarity index 100%
rename from 8086/msdos/src/blocking.fth
rename to 8086/msdos/src/blocking.fb.txt
diff --git a/8086/msdos/src/ced.fth b/8086/msdos/src/ced.fb.txt
similarity index 100%
rename from 8086/msdos/src/ced.fth
rename to 8086/msdos/src/ced.fb.txt
diff --git a/8086/msdos/src/disasm.fth b/8086/msdos/src/disasm.fb.txt
similarity index 100%
rename from 8086/msdos/src/disasm.fth
rename to 8086/msdos/src/disasm.fb.txt
diff --git a/8086/msdos/src/dos.fth b/8086/msdos/src/dos.fb.txt
similarity index 100%
rename from 8086/msdos/src/dos.fth
rename to 8086/msdos/src/dos.fb.txt
diff --git a/8086/msdos/src/double.fth b/8086/msdos/src/double.fb.txt
similarity index 100%
rename from 8086/msdos/src/double.fth
rename to 8086/msdos/src/double.fb.txt
diff --git a/8086/msdos/src/editor.fth b/8086/msdos/src/editor.fb.txt
similarity index 100%
rename from 8086/msdos/src/editor.fth
rename to 8086/msdos/src/editor.fb.txt
diff --git a/8086/msdos/src/extend.fth b/8086/msdos/src/extend.fb.txt
similarity index 100%
rename from 8086/msdos/src/extend.fth
rename to 8086/msdos/src/extend.fb.txt
diff --git a/8086/msdos/src/f83asm.fth b/8086/msdos/src/f83asm.fb.txt
similarity index 100%
rename from 8086/msdos/src/f83asm.fth
rename to 8086/msdos/src/f83asm.fb.txt
diff --git a/8086/msdos/src/include.fth b/8086/msdos/src/include.fb.txt
similarity index 100%
rename from 8086/msdos/src/include.fth
rename to 8086/msdos/src/include.fb.txt
diff --git a/8086/msdos/src/install.fth b/8086/msdos/src/install.fb.txt
similarity index 100%
rename from 8086/msdos/src/install.fth
rename to 8086/msdos/src/install.fb.txt
diff --git a/8086/msdos/src/kernel.fth b/8086/msdos/src/kernel.fb.txt
similarity index 100%
rename from 8086/msdos/src/kernel.fth
rename to 8086/msdos/src/kernel.fb.txt
diff --git a/8086/msdos/src/meta.fth b/8086/msdos/src/meta.fb.txt
similarity index 100%
rename from 8086/msdos/src/meta.fth
rename to 8086/msdos/src/meta.fb.txt
diff --git a/8086/msdos/src/miniterm.fth b/8086/msdos/src/miniterm.fb.txt
similarity index 100%
rename from 8086/msdos/src/miniterm.fth
rename to 8086/msdos/src/miniterm.fb.txt
diff --git a/8086/msdos/src/primed.fth b/8086/msdos/src/primed.fb.txt
similarity index 100%
rename from 8086/msdos/src/primed.fth
rename to 8086/msdos/src/primed.fb.txt
diff --git a/8086/msdos/src/see.fth b/8086/msdos/src/see.fb.txt
similarity index 100%
rename from 8086/msdos/src/see.fth
rename to 8086/msdos/src/see.fb.txt
diff --git a/8086/msdos/src/serial.fth b/8086/msdos/src/serial.fb.txt
similarity index 100%
rename from 8086/msdos/src/serial.fth
rename to 8086/msdos/src/serial.fb.txt
diff --git a/8086/msdos/src/stream.fth b/8086/msdos/src/stream.fb.txt
similarity index 100%
rename from 8086/msdos/src/stream.fth
rename to 8086/msdos/src/stream.fb.txt
diff --git a/8086/msdos/src/tasker.fth b/8086/msdos/src/tasker.fb.txt
similarity index 100%
rename from 8086/msdos/src/tasker.fth
rename to 8086/msdos/src/tasker.fb.txt
diff --git a/8086/msdos/src/timer.fth b/8086/msdos/src/timer.fb.txt
similarity index 100%
rename from 8086/msdos/src/timer.fth
rename to 8086/msdos/src/timer.fb.txt
diff --git a/8086/msdos/src/tools.fth b/8086/msdos/src/tools.fb.txt
similarity index 100%
rename from 8086/msdos/src/tools.fth
rename to 8086/msdos/src/tools.fb.txt
diff --git a/8086/msdos/src/v4thfile.fth b/8086/msdos/src/v4thfile.fb.txt
similarity index 100%
rename from 8086/msdos/src/v4thfile.fth
rename to 8086/msdos/src/v4thfile.fb.txt
diff --git a/8086/msdos/tests/log2file.fth b/8086/msdos/tests/log2file.fb.txt
similarity index 100%
rename from 8086/msdos/tests/log2file.fth
rename to 8086/msdos/tests/log2file.fb.txt
diff --git a/8086/msdos/tests/logtest.fth b/8086/msdos/tests/logtest.fb.txt
similarity index 100%
rename from 8086/msdos/tests/logtest.fth
rename to 8086/msdos/tests/logtest.fb.txt
diff --git a/8086/msdos/tests/testprep.fth b/8086/msdos/tests/testprep.fb.txt
similarity index 100%
rename from 8086/msdos/tests/testprep.fth
rename to 8086/msdos/tests/testprep.fb.txt