Fix PMP appspace size check

Fix AreaGrow to read appspace size correctly when appspace is a PMP
(i.e. an AMBControl node). Reading DANode_Size will only report the
amount of memory currently paged in (e.g. by lazy task swapping),
causing AreaGrow to underestimate how much it can potentially take from
the area.

s/ChangeDyn

@@ -5382,16 +5382,19 @@ AreaGrow ROUT
 
         GetAppSpaceDANode r4
         EORS    r6, r4, r12                     ; only take from app space if dest isn't app space!
-        LDRNE   r6, [r4, #DANode_Size]          ; get current size of apl space
-        LDRNE   r4, [r4, #DANode_Flags]
-        EORNE   r4, r4, #DynAreaFlags_PMP
-        TSTNE   r4, #DynAreaFlags_PMP
-        SUBNE   r6, r6, #&8000                  ; can't take away 0-&7FFF
-        ADD     r3, r2, r6, LSR #12             ; add on to amount we could remove from free pool (pages)
+        BEQ     %FT645
+        LDR     r6, [r4, #DANode_Flags]
+        TST     r6, #DynAreaFlags_PMP
+        LDRNE   r6, [r4, #DANode_PMPSize]
+        LDREQ   r6, [r4, #DANode_Size]          ; get current size of apl space
+        SUBEQ   r6, r6, #&8000                  ; can't take away 0-&7FFF
+        MOVEQ   r6, r6, LSR #12
+        ADD     r3, r2, r6                      ; add on to amount we could remove from free pool (pages)
+645
 
  [ DebugCDA2
         DREG    r6, "Can get from app space an additional ", cc
-        DREG    r3, " bytes making a total of ", cc
+        DREG    r3, " pages making a total of ", cc
         DLINE   " pages"
  ]