Fix software pointer when ExtraBytes is in use

Detail:
  s/vdu/vdupointer - The software pointer code was calculating LineLength manually, due to previous kernel versions not storing a copy of the value that would be safe to use during screen redirection.
  Fix the code to use the new DisplayLineLength variable, so that the software pointer will be correct in modes which have row padding.
Admin:
  Tested on Raspberry Pi 3


Version 5.84. Tagged as 'Kernel-5_84'

VersionASM

@@ -11,13 +11,13 @@
                         GBLS    Module_HelpVersion
                         GBLS    Module_ComponentName
                         GBLS    Module_ComponentPath
-Module_MajorVersion     SETS    "5.83"
-Module_Version          SETA    583
+Module_MajorVersion     SETS    "5.84"
+Module_Version          SETA    584
 Module_MinorVersion     SETS    ""
-Module_Date             SETS    "13 Jun 2017"
-Module_ApplicationDate  SETS    "13-Jun-17"
+Module_Date             SETS    "15 Jun 2017"
+Module_ApplicationDate  SETS    "15-Jun-17"
 Module_ComponentName    SETS    "Kernel"
 Module_ComponentPath    SETS    "castle/RiscOS/Sources/Kernel"
-Module_FullVersion      SETS    "5.83"
-Module_HelpVersion      SETS    "5.83 (13 Jun 2017)"
+Module_FullVersion      SETS    "5.84"
+Module_HelpVersion      SETS    "5.84 (15 Jun 2017)"
                         END

VersionNum

-/* (5.83)
+/* (5.84)
  *
  * This file is automatically maintained by srccommit, do not edit manually.
  * Last processed by srccommit version: 1.1.
  *
  */
-#define Module_MajorVersion_CMHG        5.83
+#define Module_MajorVersion_CMHG        5.84
 #define Module_MinorVersion_CMHG        
-#define Module_Date_CMHG                13 Jun 2017
+#define Module_Date_CMHG                15 Jun 2017
 
-#define Module_MajorVersion             "5.83"
-#define Module_Version                  583
+#define Module_MajorVersion             "5.84"
+#define Module_Version                  584
 #define Module_MinorVersion             ""
-#define Module_Date                     "13 Jun 2017"
+#define Module_Date                     "15 Jun 2017"
 
-#define Module_ApplicationDate          "13-Jun-17"
+#define Module_ApplicationDate          "15-Jun-17"
 
 #define Module_ComponentName            "Kernel"
 #define Module_ComponentPath            "castle/RiscOS/Sources/Kernel"
 
-#define Module_FullVersion              "5.83"
-#define Module_HelpVersion              "5.83 (13 Jun 2017)"
-#define Module_LibraryVersionInfo       "5:83"
+#define Module_FullVersion              "5.84"
+#define Module_HelpVersion              "5.84 (15 Jun 2017)"
+#define Module_LibraryVersionInfo       "5:84"

s/vdu/vdupointer

@@ -844,8 +844,7 @@ PlotSoftwarePointer ROUT
         CMPGT   r5, #0
         BLE     %FT99
 
-        MOV     r7, r6, LSL r9
-        MOV     r7, r7, LSR #3 ; LineLen
+        LDR     r7, [WsPtr, #DisplayLineLength]
         MLA     r0, r7, r2, r0 ; First screen row to touch
 
         MOV     r1, r1, LSL r9 ; Screen X start, in bits
@@ -881,7 +880,7 @@ PlotSoftwarePointer ROUT
         ; r3 -> initial pointer row
         ; r4 = pointer pixel width
         ; r5 = height
-        ; r7 = LineLen
+        ; r7 = LineLength
         ; r8 = pointer X start, in bits
         ; r9 = Log2BPP
         ; For 32bpp modes we have a faster plotter available
@@ -1027,11 +1026,7 @@ RemoveSoftwarePointer
         ; Get parameters needed for unplot
         LDRB    r4, [WsPtr, #SWP_W]
         LDRB    r5, [WsPtr, #SWP_H]
-        LDR     r6, [WsPtr, #DisplayXWindLimit]
-        LDRB    r9, [WsPtr, #DisplayLog2BPP]
-        ADD     r6, r6, #1
-        MOV     r6, r6, LSL r9
-        MOV     r6, r6, LSR #3
+        LDR     r6, [WsPtr, #DisplayLineLength]
         SUB     r7, r6, r4, LSL #2 ; Dest stride
         MOV     r6, #0 ; Src stride
         STR     r6, [WsPtr, #SWP_Pos]