diff --git a/Makefile b/Makefile
index e1a91a98a..22d8a01da 100644
--- a/Makefile
+++ b/Makefile
@@ -98,7 +98,7 @@ SFX.CONF=res/SFX.CONF
 PREFS.CONF.SOURCE=res/PREFS.CONF
 GAMES.CONF.SOURCE=res/GAMES.CONF
 COVER=res/COVER
-DECRUNCH=res/DECRUNCH
+DECRUNCH=build/DECRUNCH
 FINDER.DATA=res/Finder.Data
 FINDER.ROOT=res/Finder.Root
 HELP=res/HELP
@@ -437,6 +437,9 @@ $(MD):
 	touch "$(CADIUS.LOG)"
 	@touch "$@"
 
+$(DECRUNCH): $(MD)
+	$(ACME) -o $(DECRUNCH) src/decrunch/exodecrunch.a
+
 clean:
 	rm -rf "$(BUILDDIR)"/ || rm -rf "$(BUILDDIR)"
 
diff --git a/res/DECRUNCH b/res/DECRUNCH
deleted file mode 100644
index 26d949abe..000000000
Binary files a/res/DECRUNCH and /dev/null differ
diff --git a/src/decrunch/constants.a b/src/decrunch/constants.a
new file mode 100644
index 000000000..2f0ea45eb
--- /dev/null
+++ b/src/decrunch/constants.a
@@ -0,0 +1,13 @@
+!ifndef _EXO_CONSTANTS_ {
+
+zp_len_lo  = $a0
+zp_len_hi  = $a1
+zp_src_lo  = $a2
+zp_src_hi  = $a3
+zp_bits_hi = $a4
+zp_bitbuf  = $a5
+zp_dest_lo = $a6          ; dest addr lo
+zp_dest_hi = $a7          ; dest addr hi
+
+_EXO_CONSTANTS_=*
+}
diff --git a/src/decrunch/exodecrunch.a b/src/decrunch/exodecrunch.a
index 590120bf3..afe8a734e 100644
--- a/src/decrunch/exodecrunch.a
+++ b/src/decrunch/exodecrunch.a
@@ -2,7 +2,6 @@
 ; the Exomizer homepage.
 ; It contains modifications made by qkumba to work with ACME assembler.
 !cpu 6502
-!to "DECRUNCH",plain
 *=$200
 
 ;
@@ -66,17 +65,7 @@ EXTRA_TABLE_ENTRY_FOR_LENGTH_THREE = 1
 ; -------------------------------------------------------------------
 ; zero page addresses used
 ; -------------------------------------------------------------------
-zp_len_lo = $a7
-zp_len_hi = $a8
-
-zp_src_lo  = $ae
-zp_src_hi  = zp_src_lo + 1
-
-zp_bits_hi = $fc
-
-zp_bitbuf  = $fd
-zp_dest_lo = zp_bitbuf + 1      ; dest addr lo
-zp_dest_hi = zp_bitbuf + 2      ; dest addr hi
+         !src  "src/decrunch/constants.a"
 
 !IFDEF EXTRA_TABLE_ENTRY_FOR_LENGTH_THREE {
 encoded_entries = 68
diff --git a/src/index/decrunch.idx.a b/src/index/decrunch.idx.a
index 2d9c69f68..c6d8103a8 100644
--- a/src/index/decrunch.idx.a
+++ b/src/index/decrunch.idx.a
@@ -1,5 +1,5 @@
 ;
-; Index record for res/DECRUNCH
+; Index record for build/DECRUNCH
 ;
 ; This file is automatically generated
 ;