diff --git a/programs/system/launch/trunk/Tupfile.lua b/programs/system/launch/trunk/Tupfile.lua
index ff561b0899..3574746d3b 100644
--- a/programs/system/launch/trunk/Tupfile.lua
+++ b/programs/system/launch/trunk/Tupfile.lua
@@ -1,2 +1,6 @@
 if tup.getconfig("NO_FASM") ~= "" then return end
-tup.rule("launch.asm", "fasm %f %o -dlang=" .. tup.getconfig("LANG") .. tup.getconfig("KPACK_CMD"), "launch")
+HELPERDIR = (tup.getconfig("HELPERDIR") == "") and "../../.." or tup.getconfig("HELPERDIR")
+tup.include(HELPERDIR .. "/use_fasm.lua")
+
+add_include(HELPERDIR .. "/develop/libraries/libs-dev/libio")
+tup.rule("launch.asm", FASM .. " -dlang=" .. tup.getconfig("LANG") .. " %f %o" .. tup.getconfig("KPACK_CMD"), "launch")
diff --git a/programs/system/launch/trunk/launch.asm b/programs/system/launch/trunk/launch.asm
index c2f1c2de1f..960f8917c4 100755
--- a/programs/system/launch/trunk/launch.asm
+++ b/programs/system/launch/trunk/launch.asm
@@ -43,10 +43,10 @@ define DEBUG_MAX_LEN 8
 define DEBUG_DEFAULT 0
 define BUFF_SIZE 1024
 
-include '../../../proc32.inc'
-include '../../../macros.inc'
-include '../../../develop/libraries/libs-dev/libio/libio.inc'
-include '../../../dll.inc'
+include 'proc32.inc'
+include 'macros.inc'
+include 'libio.inc'
+include 'dll.inc'
 
 purge mov
 
diff --git a/programs/use_fasm.lua b/programs/use_fasm.lua
new file mode 100644
index 0000000000..a008bd7546
--- /dev/null
+++ b/programs/use_fasm.lua
@@ -0,0 +1,16 @@
+INCLUDES = ""
+FASM_DEFAULT = "fasm"
+
+function add_include(dir)
+  if INCLUDES == ""
+    then INCLUDES = dir
+    else INCLUDES = INCLUDES .. ";" .. dir
+  end
+  if tup.getconfig("TUP_PLATFORM") == "win32"
+    then env_prefix = "set INCLUDE='$(INCLUDES)'&&"
+    else env_prefix = "INCLUDE='$(INCLUDES)' "
+  end
+  FASM = env_prefix .. FASM_DEFAULT
+end
+
+add_include(tup.getcwd())