diff --git a/arch/z80/sms/xcomp.fs b/arch/z80/sms/xcomp.fs
index f477878..d00b24f 100644
--- a/arch/z80/sms/xcomp.fs
+++ b/arch/z80/sms/xcomp.fs
@@ -13,15 +13,14 @@ SYSVARS 0x73 + CONSTANT CPORT_MEM
 0xdd   CONSTANT CPORT_D2
 SYSVARS 0x74 + CONSTANT PAD_MEM
 5 LOAD  ( z80 assembler )
-: ZFILL, ( u ) 0 DO 0 C,* LOOP ;
 262 LOAD  ( xcomp )
 524 LOAD  ( font compiler )
 165 LOAD  ( Sega ROM signer )
 282 LOAD  ( boot.z80.decl )
 270 LOAD  ( xcomp overrides )
 
-DI, 0x100 JP, 0x62 ZFILL, ( 0x66 )
-RETN, 0x98 ZFILL, ( 0x100 )
+DI, 0x100 JP, 0x62 ALLOT0 ( 0x66 )
+RETN, 0x98 ALLOT0 ( 0x100 )
 ( All set, carry on! )
 CURRENT @ XCURRENT !
 0x100 BIN( !
diff --git a/arch/z80/sms/xcompkbd.fs b/arch/z80/sms/xcompkbd.fs
index 8b4234a..e8ae877 100644
--- a/arch/z80/sms/xcompkbd.fs
+++ b/arch/z80/sms/xcompkbd.fs
@@ -14,15 +14,14 @@ SYSVARS 0x73 + CONSTANT CPORT_MEM
 0xdd   CONSTANT CPORT_D2
 SYSVARS 0x74 + CONSTANT PS2_MEM
 5 LOAD  ( z80 assembler )
-: ZFILL, ( u ) 0 DO 0 C,* LOOP ;
 262 LOAD  ( xcomp )
 524 LOAD  ( font compiler )
 165 LOAD  ( Sega ROM signer )
 282 LOAD  ( boot.z80.decl )
 270 LOAD  ( xcomp overrides )
 
-DI, 0x100 JP, 0x62 ZFILL, ( 0x66 )
-RETN, 0x98 ZFILL, ( 0x100 )
+DI, 0x100 JP, 0x62 ALLOT0 ( 0x66 )
+RETN, 0x98 ALLOT0 ( 0x100 )
 ( All set, carry on! )
 CURRENT @ XCURRENT !
 0x100 BIN( !
diff --git a/arch/z80/sms/xcompsdc.fs b/arch/z80/sms/xcompsdc.fs
index b006fc1..ce9bb3f 100644
--- a/arch/z80/sms/xcompsdc.fs
+++ b/arch/z80/sms/xcompsdc.fs
@@ -15,15 +15,14 @@ SYSVARS 0x73 + CONSTANT CPORT_MEM
 0xdd   CONSTANT CPORT_D2
 SYSVARS 0x74 + CONSTANT PS2_MEM
 5 LOAD  ( z80 assembler )
-: ZFILL, ( u ) 0 DO 0 C,* LOOP ;
 262 LOAD  ( xcomp )
 524 LOAD  ( font compiler )
 165 LOAD  ( Sega ROM signer )
 282 LOAD  ( boot.z80.decl )
 270 LOAD  ( xcomp overrides )
 
-DI, 0x100 JP, 0x62 ZFILL, ( 0x66 )
-RETN, 0x98 ZFILL, ( 0x100 )
+DI, 0x100 JP, 0x62 ALLOT0 ( 0x66 )
+RETN, 0x98 ALLOT0 ( 0x100 )
 ( All set, carry on! )
 CURRENT @ XCURRENT !
 0x100 BIN( !
diff --git a/arch/z80/sms/xcomptextmode.fs b/arch/z80/sms/xcomptextmode.fs
index bbd2bce..ae8141d 100644
--- a/arch/z80/sms/xcomptextmode.fs
+++ b/arch/z80/sms/xcomptextmode.fs
@@ -15,15 +15,14 @@ SYSVARS 0x73 + CONSTANT CPORT_MEM
 0xdd   CONSTANT CPORT_D2
 SYSVARS 0x74 + CONSTANT PS2_MEM
 5 LOAD  ( z80 assembler )
-: ZFILL, ( u ) 0 DO 0 C,* LOOP ;
 262 LOAD  ( xcomp )
 523 LOAD  ( font compiler )
 165 LOAD  ( Sega ROM signer )
 282 LOAD  ( boot.z80.decl )
 270 LOAD  ( xcomp overrides )
 
-DI, 0x100 JP, 0x62 ZFILL, ( 0x66 )
-RETN, 0x98 ZFILL, ( 0x100 )
+DI, 0x100 JP, 0x62 ALLOT0 ( 0x66 )
+RETN, 0x98 ALLOT0 ( 0x100 )
 ( All set, carry on! )
 CURRENT @ XCURRENT !
 0x100 BIN( !
diff --git a/blk.fs b/blk.fs
index e26218d..aa199da 100644
--- a/blk.fs
+++ b/blk.fs
@@ -1741,14 +1741,13 @@ with "390 LOAD"
 : / /MOD NIP ;
 : MOD /MOD DROP ;
 : ALLOT HERE +! ;
-: FILL ( a n b -- )
-    SWAP 2 PICK + ( a b a+n ) ROT ( b a+n a ) DO ( b )
-        DUP I C!
-    LOOP DROP ;
-: ALLOT0 ( n -- ) H@ OVER 0 FILL ALLOT ;
 SYSVARS 0x3e + :** C@*
 SYSVARS 0x40 + :** C!*
 SYSVARS 0x42 + :** C,*
+: FILL ( a n b -- )
+    ROT> OVER ( b a n a ) + SWAP ( b a+n a ) DO ( b )
+        DUP I C!* LOOP DROP ;
+: ALLOT0 ( n -- ) H@ OVER 0 FILL ALLOT ;
 ( ----- 356 )
 SYSVARS 0x53 + :** EMIT
 : STYPE C@+ ( a len ) 0 DO C@+ EMIT LOOP DROP ;