diff --git a/TODO.txt b/TODO.txt
index fe5f93b..c0b407a 100644
--- a/TODO.txt
+++ b/TODO.txt
@@ -1,4 +1,3 @@
-* split into files
 * use linker magic to compile files separately
 * convert messy init code into completely different
   files without ifdefs (not much in common!)
diff --git a/defines.s b/defines.s
new file mode 100644
index 0000000..fa2b9be
--- /dev/null
+++ b/defines.s
@@ -0,0 +1,44 @@
+.if .def(cbmbasic1)
+CBM1 := 1
+.include "defines_cbm.s"
+.elseif .def(osi)
+OSI := 1
+.include "defines_osi.s"
+.elseif .def(applesoft)
+APPLE := 1
+.include "defines_apple.s"
+.elseif .def(kb9)
+KIM := 1
+.include "defines_kim.s"
+.elseif .def(cbmbasic2)
+CBM2 := 1
+.include "defines_cbm.s"
+.elseif .def(kbdbasic)
+KBD := 1
+.include "defines_kbd.s"
+.endif
+
+.ifdef CONFIG_SMALL
+BYTES_FP		:= 4
+.else
+BYTES_FP		:= 5
+.endif
+
+.ifdef APPLE
+BYTES_PER_ELEMENT := 6 ; ???
+.else
+BYTES_PER_ELEMENT := BYTES_FP
+.endif
+BYTES_PER_VARIABLE := BYTES_FP+2
+MANTISSA_BYTES	:= BYTES_FP-1
+BYTES_PER_FRAME := 2*BYTES_FP+8
+FOR_STACK1		:= 2*BYTES_FP+5
+FOR_STACK2		:= BYTES_FP+4
+
+.ifdef CBM1
+MAX_EXPON = 12
+.else
+MAX_EXPON = 10
+.endif
+
+STACK           := $0100
diff --git a/header.s b/header.s
new file mode 100644
index 0000000..10ef261
--- /dev/null
+++ b/header.s
@@ -0,0 +1,5 @@
+		.segment "HEADER"
+.ifdef KBD
+        jmp     LE68C
+        .byte   $00,$13,$56
+.endif
diff --git a/msbasic.s b/msbasic.s
index 7b0a1c8..d4075e0 100644
--- a/msbasic.s
+++ b/msbasic.s
@@ -2,104 +2,34 @@
 
 .debuginfo +
 
-.if .def(cbmbasic1)
-CBM1 := 1
-.include "defines_cbm.s"
-.elseif .def(osi)
-OSI := 1
-.include "defines_osi.s"
-.elseif .def(applesoft)
-APPLE := 1
-.include "defines_apple.s"
-.elseif .def(kb9)
-KIM := 1
-.include "defines_kim.s"
-.elseif .def(cbmbasic2)
-CBM2 := 1
-.include "defines_cbm.s"
-.elseif .def(kbdbasic)
-KBD := 1
-.include "defines_kbd.s"
-.endif
-
-.ifdef CONFIG_SMALL
-BYTES_FP		:= 4
-.else
-BYTES_FP		:= 5
-.endif
-
-.ifdef APPLE
-BYTES_PER_ELEMENT := 6 ; ???
-.else
-BYTES_PER_ELEMENT := BYTES_FP
-.endif
-BYTES_PER_VARIABLE := BYTES_FP+2
-MANTISSA_BYTES	:= BYTES_FP-1
-BYTES_PER_FRAME := 2*BYTES_FP+8
-FOR_STACK1		:= 2*BYTES_FP+5
-FOR_STACK2		:= BYTES_FP+4
-
-.ifdef CBM1
-MAX_EXPON = 12
-.else
-MAX_EXPON = 10
-.endif
-
+.setcpu "6502"
+.macpack longbranch
 
+.include "defines.s"
 .include "macros.s"
 .include "zeropage.s"
 
-        .setcpu "6502"
-		.macpack longbranch
-
-STACK           := $0100
-
-		.segment "HEADER"
-.ifdef KBD
-        jmp     LE68C
-        .byte   $00,$13,$56
-.endif
-
+.include "header.s"
 .include "token.s"
-
 .include "error.s"
-
 .include "message.s"
-
 .include "memory.s"
-
 .include "program.s"
-
 .include "flow.s"
-
 .include "misc1.s"
-
 .include "print.s"
-
 .include "input.s"
-
 .include "eval.s"
-
 .include "var.s"
-
 .include "array.s"
-
 .include "misc2.s"
-
 .include "string.s"
-
 .include "misc3.s"
-
 .ifndef KBD
 .include "poke.s"
 .endif
-
 .include "float.s"
-
 .include "chrget.s"
-
 .include "rnd.s"
-
 .include "trig.s"
-
 .include "init.s"
diff --git a/zeropage.s b/zeropage.s
index 154f535..7dd5db2 100644
--- a/zeropage.s
+++ b/zeropage.s
@@ -118,3 +118,5 @@ TXTPTR = <(GENERIC_TXTPTR-GENERIC_CHRGET + CHRGET)
 L00CF:
 RNDSEED = <(GENERIC_RNDSEED-GENERIC_CHRGET + CHRGET)
 .endif
+
+