diff --git a/blk/290 b/blk/290
index 5380427..2f66532 100644
--- a/blk/290
+++ b/blk/290
@@ -1,10 +1,7 @@
-lbluflw BSET ( abortUnderflow )
-    DE BIN( @ 0x06 ( uflw ) + LDd(i),
-    JR, lblexec BWR
 lblchkPS BSET ( chkPS )
-( Note that you only need to call this in words that push
-  back to PSP. If they don't, calling chkPS is redundant with
-  check in next )
+    ( thread carefully in there: sometimes, we're in the
+      middle of a EXX to protect BC. BC must never be touched
+      here. )
     EXX,
 ( We have the return address for this very call on the stack
   and protected registers. 2- is to compensate that. )
@@ -12,4 +9,7 @@ lblchkPS BSET ( chkPS )
     SP SUBHLd,
     EXX,
     CNC RETc, ( PS_ADDR >= SP? good )
-    JR, lbluflw BWR
+    ( continue to uflw )
+lbluflw BSET ( abortUnderflow )
+    DE BIN( @ 0x06 ( uflw ) + LDd(i),
+    JR, lblexec BWR
diff --git a/blk/308 b/blk/308
index 8c69522..b75639a 100644
--- a/blk/308
+++ b/blk/308
@@ -12,5 +12,5 @@ CODE ?DUP
     HLZ, IFNZ, HL PUSH, THEN,
 ;CODE
 CODE DROP ( a -- )
-    HL POP,
+    HL POP, chkPS,
 ;CODE
diff --git a/blk/312 b/blk/312
index 180c760..9be0e6f 100644
--- a/blk/312
+++ b/blk/312
@@ -1,5 +1,5 @@
 CODE 2DROP ( a b -- )
-    HL POP, HL POP,
+    HL POP, HL POP, chkPS,
 ;CODE
 
 CODE 2DUP ( a b -- a b a b )
diff --git a/blk/322 b/blk/322
index b1b28fc..d67257c 100644
--- a/blk/322
+++ b/blk/322
@@ -1,13 +1,11 @@
 CODE !
-    HL POP,
-    DE POP,
+    HL POP, DE POP, chkPS,
     (HL) E LDrr,
     HL INCd,
     (HL) D LDrr,
 ;CODE
 CODE @
-    HL POP,
-    chkPS,
+    HL POP, chkPS,
     E (HL) LDrr,
     HL INCd,
     D (HL) LDrr,
diff --git a/blk/323 b/blk/323
index 55c4dbb..7090be3 100644
--- a/blk/323
+++ b/blk/323
@@ -1,12 +1,10 @@
 CODE C!
-    HL POP,
-    DE POP,
+    HL POP, DE POP, chkPS,
     (HL) E LDrr,
 ;CODE
 
 CODE C@
-    HL POP,
-    chkPS,
+    HL POP, chkPS,
     L (HL) LDrr,
     H 0 LDri,
     HL PUSH,
diff --git a/blk/324 b/blk/324
index 5c0eb54..c76b669 100644
--- a/blk/324
+++ b/blk/324
@@ -1,12 +1,10 @@
 CODE PC! EXX, ( protect BC )
-    BC POP,
-    HL POP,
+    BC POP, HL POP, chkPS,
     L OUT(C)r,
 EXX, ( unprotect BC ) ;CODE
 
 CODE PC@ EXX, ( protect BC )
-    BC POP,
-    chkPS,
+    BC POP, chkPS,
     H 0 LDri,
     L INr(C),
     HL PUSH,
diff --git a/blk/325 b/blk/325
index bd35998..5d661be 100644
--- a/blk/325
+++ b/blk/325
@@ -1,15 +1,16 @@
 CODE I
-    L 0 IX+ LDrIXY,
-    H 1 IX+ LDrIXY,
+    L 0 IX+ LDrIXY, H 1 IX+ LDrIXY,
     HL PUSH,
 ;CODE
 CODE I'
-    L 2 IX- LDrIXY,
-    H 1 IX- LDrIXY,
+    L 2 IX- LDrIXY, H 1 IX- LDrIXY,
     HL PUSH,
 ;CODE
 CODE J
-    L 4 IX- LDrIXY,
-    H 3 IX- LDrIXY,
+    L 4 IX- LDrIXY, H 3 IX- LDrIXY,
     HL PUSH,
 ;CODE
+CODE >R
+    HL POP, chkPS,
+    IX INCd, IX INCd, 0 IX+ L LDIXYr, 1 IX+ H LDIXYr,
+;CODE
diff --git a/blk/326 b/blk/326
index 7c380b5..dc5676f 100644
--- a/blk/326
+++ b/blk/326
@@ -1,11 +1,8 @@
-CODE >R
-    HL POP, IX INCd, IX INCd, 0 IX+ L LDIXYr, 1 IX+ H LDIXYr,
-;CODE
 CODE R>
     L 0 IX+ LDrIXY, H 1 IX+ LDrIXY, IX DECd, IX DECd, HL PUSH,
 ;CODE
 CODE 2>R PC ORG @ 0x35 + ! ( stable ABI JP )
-    DE POP, HL POP,
+    DE POP, HL POP, chkPS,
     IX INCd, IX INCd, 0 IX+ L LDIXYr, 1 IX+ H LDIXYr,
     IX INCd, IX INCd, 0 IX+ E LDIXYr, 1 IX+ D LDIXYr,
 ;CODE