Added Bombos platform in first Ice Palace room

icepalacegraphics.asm

@@ -0,0 +1,47 @@
+BgGraphicsLoading:
+    ; Instructions overwritten
+    STZ $00
+    STX $01
+    STA $02
+
+    ; Y = Graphics file being loaded
+    CPY #$0A ; 0A = Ice/Mire floor file
+    BNE .useDefaultGraphics
+
+    LDA $040C ; Dungeon number
+    CMP #$12 ; Ice Palace
+    BEQ .useSpecialIcePalaceFile
+
+.useDefaultGraphics
+    JML BgGraphicsLoadingResume
+
+.useSpecialIcePalaceFile
+    ; We're loading the floor tiles in Ice Palace. Instead of the normal file,
+    ; load another one that replaces the bridge tiles with the Bombos medallion
+
+    LDA $FFFFFF
+
+    LDA.b #IcePalaceFloorGfx>>16
+    STA $02
+    REP #$20
+    LDA.w #IcePalaceFloorGfx
+    STA $00
+    LDX.b #64*2 ; Tiles to load * 2
+-
+    ; Unrolled loop to upload half a tile
+    LDA [$00] : STA $2118 : INC $00 : INC $00
+    LDA [$00] : STA $2118 : INC $00 : INC $00
+    LDA [$00] : STA $2118 : INC $00 : INC $00
+    LDA [$00] : STA $2118 : INC $00 : INC $00
+    LDA [$00] : STA $2118 : INC $00 : INC $00
+    LDA [$00] : STA $2118 : INC $00 : INC $00
+    LDA [$00] : STA $2118 : INC $00 : INC $00
+    LDA [$00] : STA $2118 : INC $00 : INC $00
+    DEX
+    BNE -
+
+    SEP #$20
+    JML BgGraphicsLoadingCancel
+
+IcePalaceFloorGfx:
+    incbin ice_palace_floor.bin