Fix stack imbalance and incorrect return value in OS_DynamicArea 23 (PMP resize)

Detail:
  s/ChangeDyn - When OS_DynamicArea 23 returned an error, R2 wasn't being set to zero correctly, incorrectly suggesting that a change had been made. And when a non-error resize of zero was being performed, registers were being pulled twice, resulting in a stack imbalance and crash.
Admin:
  Tested on BB-xM


Version 5.58. Tagged as 'Kernel-5_58'

VersionASM

@@ -11,13 +11,13 @@
                         GBLS    Module_HelpVersion
                         GBLS    Module_ComponentName
                         GBLS    Module_ComponentPath
-Module_MajorVersion     SETS    "5.57"
-Module_Version          SETA    557
+Module_MajorVersion     SETS    "5.58"
+Module_Version          SETA    558
 Module_MinorVersion     SETS    ""
-Module_Date             SETS    "18 Aug 2016"
-Module_ApplicationDate  SETS    "18-Aug-16"
+Module_Date             SETS    "23 Aug 2016"
+Module_ApplicationDate  SETS    "23-Aug-16"
 Module_ComponentName    SETS    "Kernel"
 Module_ComponentPath    SETS    "castle/RiscOS/Sources/Kernel"
-Module_FullVersion      SETS    "5.57"
-Module_HelpVersion      SETS    "5.57 (18 Aug 2016)"
+Module_FullVersion      SETS    "5.58"
+Module_HelpVersion      SETS    "5.58 (23 Aug 2016)"
                         END

VersionNum

-/* (5.57)
+/* (5.58)
  *
  * This file is automatically maintained by srccommit, do not edit manually.
  * Last processed by srccommit version: 1.1.
  *
  */
-#define Module_MajorVersion_CMHG        5.57
+#define Module_MajorVersion_CMHG        5.58
 #define Module_MinorVersion_CMHG        
-#define Module_Date_CMHG                18 Aug 2016
+#define Module_Date_CMHG                23 Aug 2016
 
-#define Module_MajorVersion             "5.57"
-#define Module_Version                  557
+#define Module_MajorVersion             "5.58"
+#define Module_Version                  558
 #define Module_MinorVersion             ""
-#define Module_Date                     "18 Aug 2016"
+#define Module_Date                     "23 Aug 2016"
 
-#define Module_ApplicationDate          "18-Aug-16"
+#define Module_ApplicationDate          "23-Aug-16"
 
 #define Module_ComponentName            "Kernel"
 #define Module_ComponentPath            "castle/RiscOS/Sources/Kernel"
 
-#define Module_FullVersion              "5.57"
-#define Module_HelpVersion              "5.57 (18 Aug 2016)"
-#define Module_LibraryVersionInfo       "5:57"
+#define Module_FullVersion              "5.58"
+#define Module_HelpVersion              "5.58 (23 Aug 2016)"
+#define Module_LibraryVersionInfo       "5:58"

s/ChangeDyn

@@ -3459,21 +3459,18 @@ DynArea_PMP_Resize ROUT
  |
         SETV
  ]
+        FRAMSTR r0
+98
       [ PMPParanoid
         BL      ValidatePMPs
       ]
-        FRAMSTR r0
+        PullEnv
         MOV     r2, #0
-        EXIT
+        MOV     pc, lr
 
 99
-        PullEnv
         CLRV
-        MOV     r2, #0
-      [ PMPParanoid
-        BL      ValidatePMPs
-      ]
-        EXIT
+        B       %BT98
 
 
 ;**************************************************************************