Fix PreCreateHeader to allow palettes for <=256 colour RISC OS 5 sprites. LoadCoordPair tweaks.

Detail:
  s/vdu/vdudecl - Add a couple more optimisations to LoadCoordPair - use SXTH where possible, and use LDRSH if data is halfword aligned (not currently the case, but may be in future)
  s/vdu/vdugrafj - Fix PreCreateHeader to allow <=256 colour RISC OS 5 sprites to have palettes
Admin:
  Tested on Pandaboard


Version 5.35, 4.79.2.238. Tagged as 'Kernel-5_35-4_79_2_238'

VersionASM

@@ -13,11 +13,11 @@
                         GBLS    Module_ComponentPath
 Module_MajorVersion     SETS    "5.35"
 Module_Version          SETA    535
-Module_MinorVersion     SETS    "4.79.2.237"
-Module_Date             SETS    "16 Sep 2014"
-Module_ApplicationDate  SETS    "16-Sep-14"
+Module_MinorVersion     SETS    "4.79.2.238"
+Module_Date             SETS    "18 Sep 2014"
+Module_ApplicationDate  SETS    "18-Sep-14"
 Module_ComponentName    SETS    "Kernel"
 Module_ComponentPath    SETS    "castle/RiscOS/Sources/Kernel"
-Module_FullVersion      SETS    "5.35 (4.79.2.237)"
-Module_HelpVersion      SETS    "5.35 (16 Sep 2014) 4.79.2.237"
+Module_FullVersion      SETS    "5.35 (4.79.2.238)"
+Module_HelpVersion      SETS    "5.35 (18 Sep 2014) 4.79.2.238"
                         END

VersionNum

@@ -5,19 +5,19 @@
  *
  */
 #define Module_MajorVersion_CMHG        5.35
-#define Module_MinorVersion_CMHG        4.79.2.237
-#define Module_Date_CMHG                16 Sep 2014
+#define Module_MinorVersion_CMHG        4.79.2.238
+#define Module_Date_CMHG                18 Sep 2014
 
 #define Module_MajorVersion             "5.35"
 #define Module_Version                  535
-#define Module_MinorVersion             "4.79.2.237"
-#define Module_Date                     "16 Sep 2014"
+#define Module_MinorVersion             "4.79.2.238"
+#define Module_Date                     "18 Sep 2014"
 
-#define Module_ApplicationDate          "16-Sep-14"
+#define Module_ApplicationDate          "18-Sep-14"
 
 #define Module_ComponentName            "Kernel"
 #define Module_ComponentPath            "castle/RiscOS/Sources/Kernel"
 
-#define Module_FullVersion              "5.35 (4.79.2.237)"
-#define Module_HelpVersion              "5.35 (16 Sep 2014) 4.79.2.237"
+#define Module_FullVersion              "5.35 (4.79.2.238)"
+#define Module_HelpVersion              "5.35 (18 Sep 2014) 4.79.2.238"
 #define Module_LibraryVersionInfo       "5:35"

s/vdu/vdudecl

@@ -201,14 +201,19 @@ GVDriverState_Started       *   1:SHL:0  ; ScreenMode_StartDriver called
 
         MACRO
         LoadCoordPair   $x, $y, $basereg, $offset
+    [ NoARMv4 :LOR: (($offset :AND: 1)=1)
       [ NoARMv6 :LOR: NoUnaligned
         ASSERT  $x < $y
         [ ($offset) :AND: 3 = 2
           ADD   $x, $basereg, #($offset)-2
           LDMIA $x, {$x, $y}                ; (Xh,Xl,??,??) (??,??,Yh,Yl)
           MOV   $x, $x, ASR #16             ; (Xs,Xs,Xh,Xl)
-          MOV   $y, $y, LSL #16             ;               (Yh,Yl, 0, 0)
-          MOV   $y, $y, ASR #16             ;               (Ys,Ys,Yh,Yl)
+          [ NoARMv6
+            MOV   $y, $y, LSL #16           ;               (Yh,Yl, 0, 0)
+            MOV   $y, $y, ASR #16           ;               (Ys,Ys,Yh,Yl)
+          |
+            SXTH  $y, $y                    ;               (Ys,Ys,Yh,Yl)
+          ]
         |
           [ ($offset) :AND: 3 = 0
             LDR   $x, [$basereg, #$offset]  ; (Yh,Yl,Xh,Xl)
@@ -226,14 +231,23 @@ GVDriverState_Started       *   1:SHL:0  ; ScreenMode_StartDriver called
           ]
           ]
           MOV   $y, $x, ASR #16             ;               (Ys,Ys,Yh,Yl)
-          MOV   $x, $x, LSL #16             ; (Xh,Xl, 0, 0)
-          MOV   $x, $x, ASR #16             ; (Xs,Xs,Xh,Xl)
+          [ NoARMv6
+            MOV   $x, $x, LSL #16           ; (Xh,Xl, 0, 0)
+            MOV   $x, $x, ASR #16           ; (Xs,Xs,Xh,Xl)
+          |
+            SXTH  $x, $x                    ; (Xs,Xs,Xh,Xl)
+          ]
         ]
       |
         ; Use unaligned loads from ARMv6
         LDRSH   $x, [$basereg, #$offset]
         LDRSH   $y, [$basereg, #($offset)+2]
       ]
+    |
+        ; Aligned halfwords
+        LDRSH   $x, [$basereg, #$offset]
+        LDRSH   $y, [$basereg, #($offset)+2]
+    ]
         MEND
 
 ;

s/vdu/vdugrafj

@@ -781,10 +781,13 @@ PreCreateHeader ROUT
 ;        MOVS    LR, LR, LSR #27         ; set NE if new
 ;        MOVNE   R3, #0                  ; turn off palette
 
-        LDR     LR, [WsPtr, #SGetMode]   ; get the sprite mode word
-        MOV     LR, LR, LSR #27          ; isolate the sprite type
-        CMP     LR, #SpriteType_New16bpp ; check for 16/32bpp
-        MOVCS   R3, #0                   ; turn off the palette request
+        LDR     LR, [WsPtr, #SGetMode]  ; get the sprite mode word
+        BIC     LR, LR, #&80000000      ; ignore alpha mask flag
+        CMP     LR, #SpriteType_RISCOS5<<27
+        MOVLO   LR, LR, LSR #7          ; shift sprite type to its RISC OS 5 location
+        ANDHS   LR, LR, #127<<20        ; or get RISC OS 5 type as-is
+        CMP     LR, #SpriteType_New16bpp<<20 ; check for true colour
+        MOVHS   R3, #0                  ; turn off the palette request
 
         TEQ     R3, #0                  ; convert R3 into mask to (ex/in)clude
         MOVNE   R3, #&FF                ; space for palette data