diff --git a/basis/cpu/x86/bootstrap.factor b/basis/cpu/x86/bootstrap.factor
index fcd8ed0eee..fc7fbc88b9 100644
--- a/basis/cpu/x86/bootstrap.factor
+++ b/basis/cpu/x86/bootstrap.factor
@@ -194,7 +194,7 @@ big-endian off
     [
         ! Untag temp0
         temp0 tag-mask get bitnot AND
-        ! Set temp1 to 0 for objects, and 8 for tuples
+        ! Set temp1 to 0 for objects, and bootstrap-cell for tuples
         temp1 1 tag-fixnum AND
         bootstrap-cell 4 = [ temp1 1 SHR ] when
         ! Load header cell or tuple layout cell
diff --git a/vm/cpu-x86.32.S b/vm/cpu-x86.32.S
index 3c0db36935..0c08ea7b46 100755
--- a/vm/cpu-x86.32.S
+++ b/vm/cpu-x86.32.S
@@ -30,7 +30,6 @@ and the callstack top is passed in EDX */
 	pop %ebx
 
 #define QUOT_XT_OFFSET 16
-#define WORD_XT_OFFSET 30
 
 /* We pass a function pointer to memcpy to work around a Mac OS X
 ABI limitation which would otherwise require us to do a bizzaro PC-relative
diff --git a/vm/cpu-x86.64.S b/vm/cpu-x86.64.S
index a110bf1d51..5a70280ddf 100644
--- a/vm/cpu-x86.64.S
+++ b/vm/cpu-x86.64.S
@@ -62,7 +62,6 @@
 #endif
 
 #define QUOT_XT_OFFSET 36
-#define WORD_XT_OFFSET 66
 
 /* We pass a function pointer to memcpy to work around a Mac OS X
 ABI limitation which would otherwise require us to do a bizzaro PC-relative