Change to RMA shrinkage in *ICONSPRITES pre Medusa

On completing the sprite area merge the Wimp would try to minimise the RMA by -256MB (to account for the fact that during the merge the RMA is enlarged to hold both the existing sprites and the new ones to be merged, in the case of duplicates).
However, this meant that the common construct

  IconSprites MySprites
  Run MyApp

where MyApp wanted to use more than a teaspoon of RMA would fail due to the lack of free pool and that the RMA can't be resized when an application is running as a result.

Now, the Wimp notes the free space in the RMA, does the -256MB shrink, then ensures there's still the same free space after the event (ie. overall it may have grown by the size of any extra sprites added during the command).
Tested on RISC OS 3.10.

Version 5.26. Tagged as 'Wimp-5_26'

VersionASM

@@ -11,13 +11,13 @@
                         GBLS    Module_HelpVersion
                         GBLS    Module_ComponentName
                         GBLS    Module_ComponentPath
-Module_MajorVersion     SETS    "5.25"
-Module_Version          SETA    525
+Module_MajorVersion     SETS    "5.26"
+Module_Version          SETA    526
 Module_MinorVersion     SETS    ""
-Module_Date             SETS    "06 May 2013"
-Module_ApplicationDate  SETS    "06-May-13"
+Module_Date             SETS    "09 May 2013"
+Module_ApplicationDate  SETS    "09-May-13"
 Module_ComponentName    SETS    "Wimp"
 Module_ComponentPath    SETS    "castle/RiscOS/Sources/Desktop/Wimp"
-Module_FullVersion      SETS    "5.25"
-Module_HelpVersion      SETS    "5.25 (06 May 2013)"
+Module_FullVersion      SETS    "5.26"
+Module_HelpVersion      SETS    "5.26 (09 May 2013)"
                         END

VersionNum

-/* (5.25)
+/* (5.26)
  *
  * This file is automatically maintained by srccommit, do not edit manually.
  * Last processed by srccommit version: 1.1.
  *
  */
-#define Module_MajorVersion_CMHG        5.25
+#define Module_MajorVersion_CMHG        5.26
 #define Module_MinorVersion_CMHG        
-#define Module_Date_CMHG                06 May 2013
+#define Module_Date_CMHG                09 May 2013
 
-#define Module_MajorVersion             "5.25"
-#define Module_Version                  525
+#define Module_MajorVersion             "5.26"
+#define Module_Version                  526
 #define Module_MinorVersion             ""
-#define Module_Date                     "06 May 2013"
+#define Module_Date                     "09 May 2013"
 
-#define Module_ApplicationDate          "06-May-13"
+#define Module_ApplicationDate          "09-May-13"
 
 #define Module_ComponentName            "Wimp"
 #define Module_ComponentPath            "castle/RiscOS/Sources/Desktop/Wimp"
 
-#define Module_FullVersion              "5.25"
-#define Module_HelpVersion              "5.25 (06 May 2013)"
-#define Module_LibraryVersionInfo       "5:25"
+#define Module_FullVersion              "5.26"
+#define Module_HelpVersion              "5.26 (09 May 2013)"
+#define Module_LibraryVersionInfo       "5:26"

s/Wimp01

@@ -2853,9 +2853,16 @@ greys_16
 ; tries "<filename>23" if hi-res mono, and/or "<filename>22" if 2x2 OS units
 
 IconSprites_Code
-        Push    "R7-R8,LR"
+        Push    "R7-R9,LR"
         LDR     wsptr,[R12]
 ;
+      [ :LNOT: Medusa
+        Push    "R0"
+        MOV     R0,#ModHandReason_RMADesc
+        SWI     XOS_Module
+        MOV     R9,R3                   ; how much free RMA there was before merging
+        Pull    "R0"
+      ]
         MOV     R8,R0                   ; R8 -> original filename
         MOV     R5,R0                   ; R5 = position at which to insert system variable
 01      LDRB    LR,[R0],#1              ; skip leading space
@@ -2933,7 +2940,7 @@ IconSprites_Code
         TEQ     R3,R8                   ; were we trying with the system variable inserted?
         ADDNE   SP,SP,R7                ; yes, so junk stack frame
         BVC     %FT04
-        BEQ     %FT05                   ; no, and an error, so give up
+        BEQ     %FT95                   ; no, and an error, so give up
         MOV     R3,R8                   ; yes, and an error, so try again without the system variable
         B       %BT01
 04
@@ -2949,14 +2956,16 @@ IconSprites_Code
  ]
 
       [ :LNOT: Medusa                   ; Medusa uses DA
-; this merge bumps the RMA up, compress it again just in case.
+        MOV     R0,#1                   ; The merge might have bumped up the RMA while both sets of sprites
+        MOV     R1,#-&10000000          ; were loaded. Try and shrink RMA.
+        SWI     XOS_ChangeDynamicArea   ; -256M will give "Unable to move memory"
         MOV     R0,#1
-        MOV     R1,#-&10000000           ; try and shrink RMA
-        SWI     XOS_ChangeDynamicArea
-        CLRV                            ; may cause an error, but ok.
+        MOV     R1,R9                   ; Put back the same amount of free space as on entry
+        SWI     XOS_ChangeDynamicArea   ; May fail if APPSPACE is in use, that's ok.
+        CLRV
       ]
-05
-        Pull    "R7-R8,PC"
+95
+        Pull    "R7-R9,PC"
 
 IconThemeSysVar = "<Wimp$IconTheme>"
 IconThemeSysVarLen * . - IconThemeSysVar