diff --git a/blk/671 b/blk/671
index 95bf3c5..4dfafb4 100644
--- a/blk/671
+++ b/blk/671
@@ -1,13 +1,14 @@
 ( L1 LBL! .. L1 ' RJMP LBL, )
 : LBL! ( l -- ) PC SWAP ! ;
 : LBL, ( l op -- ) SWAP @ 1- SWAP EXECUTE A,, ;
-( L1 FLBL, .. L1 ' RJMP FLBL! )
-: FLBL, ( l -- ) LBL! 0 A,, ;
-: FLBL! ( l opw -- )
-    ( warning: l is a PC offset, not a mem addr! )
-    SWAP @ 2 * ORG @ + PC 1- H@ ( opw addr tgt hbkp )
+: SKIP, PC 0 A,, ;
+: AT, ( opw pc )
+    ( warning: pc is a PC offset, not a mem addr! )
+    2 * ORG @ + PC 1- H@ ( opw addr tgt hbkp )
     ROT HERE ! ( opw tgt hbkp ) SWAP ROT EXECUTE H@ ! ( hbkp )
     HERE ! ;
+( L1 FLBL, .. L1 ' RJMP FLBL! )
+: FLBL, ( l -- ) LBL! 0 A,, ;
+: FLBL! ( l opw -- ) SWAP @ AT, ;
 : BEGIN, PC ;
 : AGAIN, ( op ) SWAP 1- SWAP EXECUTE A,, ;
-
diff --git a/recipes/sms/kbd/ps2ctl.fs b/recipes/sms/kbd/ps2ctl.fs
index 68fb006..a256a47 100644
--- a/recipes/sms/kbd/ps2ctl.fs
+++ b/recipes/sms/kbd/ps2ctl.fs
@@ -297,3 +297,29 @@ RET,
 L8 ' RCALL FLBL! ( checkBoundsY )
 ( Check that Y is within bounds, reset to SRAM_START if not. )
 28 ( YL ) TST,
+' BREQ SKIP, RET, ( not zero, nothing to do ) AT,
+( YL is zero. Reset Z )
+29 ( YH ) CLR,
+28 ( YL ) SRAM_START 0xff AND LDI,
+RET,
+
+L3 ' RCALL FLBL! ( checkBoundsZ )
+( Check that Z is within bounds, reset to SRAM_START if not. )
+30 ( ZL ) TST,
+' BREQ SKIP, RET, ( not zero, nothing to do ) AT,
+( ZL is zero. Reset Z )
+31 ( ZH ) CLR,
+30 ( ZL ) SRAM_START 0xff AND LDI,
+RET,
+
+L5 ' RCALL FLBL! L6 ' RCALL FLBL! ( checkParity )
+( Counts the number of 1s in r19 and set r16 to 1 if there's an
+  even number of 1s, 0 if they're odd. )
+16 1 LDI,
+BEGIN,
+    19 LSR,
+    ' BRCC SKIP, 16 INC, ( carry set? we had a 1 ) AT,
+    19 TST, ( is r19 zero yet? )
+' BRNE AGAIN, ( no? loop )
+16 0x1 ANDI,
+RET,