diff --git a/basis/cpu/x86/32/32.factor b/basis/cpu/x86/32/32.factor
index c095f5493c..60d2a42c01 100755
--- a/basis/cpu/x86/32/32.factor
+++ b/basis/cpu/x86/32/32.factor
@@ -25,6 +25,18 @@ M: x86.32 rs-reg EDI ;
 M: x86.32 stack-reg ESP ;
 M: x86.32 temp-reg ECX ;
 
+M: x86.32 %mark-card
+    drop HEX: ffffffff [+] card-mark <byte> MOV
+    building get pop
+    rc-absolute-cell rel-cards-offset
+    building get push ;
+
+M: x86.32 %mark-deck
+    drop HEX: ffffffff [+] card-mark <byte> MOV
+    building get pop
+    rc-absolute-cell rel-decks-offset
+    building get push ;
+
 M:: x86.32 %dispatch ( src temp -- )
     ! Load jump table base.
     temp src HEX: ffffffff [+] LEA
diff --git a/basis/cpu/x86/64/64.factor b/basis/cpu/x86/64/64.factor
index c15169dd89..4674413e75 100644
--- a/basis/cpu/x86/64/64.factor
+++ b/basis/cpu/x86/64/64.factor
@@ -21,6 +21,20 @@ M: x86.64 ds-reg R14 ;
 M: x86.64 rs-reg R15 ;
 M: x86.64 stack-reg RSP ;
 
+: load-cards-offset ( dst -- )
+    0 MOV rc-absolute-cell rel-cards-offset ;
+
+M: x86.64 %mark-card
+    dup load-cards-offset
+    [+] card-mark <byte> MOV ;
+
+: load-decks-offset ( dst -- )
+    0 MOV rc-absolute-cell rel-decks-offset ;
+
+M: x86.64 %mark-deck
+    dup load-cards-offset
+    [+] card-mark <byte> MOV ;
+
 M:: x86.64 %dispatch ( src temp -- )
     building get length :> start
     ! Load jump table base.
diff --git a/basis/cpu/x86/x86.factor b/basis/cpu/x86/x86.factor
index abe6d308b8..60d47b78ff 100644
--- a/basis/cpu/x86/x86.factor
+++ b/basis/cpu/x86/x86.factor
@@ -387,31 +387,21 @@ M: x86 %vm-field-ptr ( dst field -- )
 : store-tagged ( dst tag -- )
     tag-number OR ;
 
-: load-cards-offset ( dst -- )
-    0 MOV rc-absolute-cell rel-cards-offset ;
-
-: load-decks-offset ( dst -- )
-    0 MOV rc-absolute-cell rel-decks-offset ;
-
 M:: x86 %allot ( dst size class nursery-ptr -- )
     nursery-ptr dst load-allot-ptr
     dst class store-header
     dst class store-tagged
     nursery-ptr size inc-allot-ptr ;
 
+HOOK: %mark-card cpu ( card temp -- )
+HOOK: %mark-deck cpu ( card temp -- )
+
 :: (%write-barrier) ( src slot temp1 temp2 -- )
-    ! Compute slot address.
     temp1 src slot [+] LEA
-
-    ! Mark the card
     temp1 card-bits SHR
-    temp2 load-cards-offset
-    temp2 temp1 [+] card-mark <byte> MOV
-
-    ! Mark the card deck
+    temp1 temp2 %mark-card
     temp1 deck-bits card-bits - SHR
-    temp2 load-decks-offset
-    temp2 temp1 [+] card-mark <byte> MOV ;
+    temp1 temp2 %mark-deck ;
 
 M: x86 %write-barrier ( src slot temp1 temp2 -- ) (%write-barrier) ;