diff --git a/build-image.bat b/build-image.bat
new file mode 100644
index 0000000..343d3fb
--- /dev/null
+++ b/build-image.bat
@@ -0,0 +1,18 @@
+echo off
+
+REM Copy all of the assets into the ProDOS image for emulator testing
+REM
+REM Pass the path of the Cadius tool as the first argument (%1)
+
+set CADIUS="%1"
+set IMAGE=".\\emu\\Target.2mg"
+set FOLDER="/GTEDEV/Toolbox"
+
+REM Cadius does not overwrite files, so clear the root folder first
+%CADIUS% DELETEFOLDER %IMAGE% %FOLDER%
+%CADIUS% CREATEFOLDER %IMAGE% %FOLDER%
+
+REM Now copy files and folders as needed
+%CADIUS% ADDFILE %IMAGE% %FOLDER% .\src\GTETool
+
+REM Copy in the image assets
diff --git a/demos/tool/App.Main.s b/demos/tool/App.Main.s
new file mode 100644
index 0000000..7f89d59
--- /dev/null
+++ b/demos/tool/App.Main.s
@@ -0,0 +1,83 @@
+                REL
+                DSK   MAINSEG
+
+                use   Locator.Macs
+                use   Load.Macs
+                use   Mem.Macs
+                use   Misc.Macs
+                use   Util.Macs
+                use   EDS.GSOS.Macs
+
+_GTEStartUp     MAC
+                UserTool  $02A0
+                <<<
+
+; Typical init
+                phk
+                plb
+
+                jsr   ToolStartUp             ; Start up the basic tools: Locator, Memory Manager, Misc
+                jsr   GTEStartUp
+
+                _QuitGS qtRec
+
+                bcs        Fatal
+Fatal           brk        $00
+qtRec           adrl       $0000
+                da         $00
+
+ToolStartUp
+                _TLStartUp                    ; normal tool initialization
+                pha
+                _MMStartUp
+                pla
+                sta   MasterId                ; our master handle references the memory allocated to us
+                ora   #$0100                  ; set auxID = $01  (valid values $01-0f)
+                sta   UserId                  ; any memory we request must use our own id 
+
+                _MTStartUp
+                rts
+
+; Load the GTE User Tool and register it
+GTEStartUp
+                pea   $0000
+                pea   $0000
+                pea   $0000
+                pea   $0000
+                pea   $0000                   ; result space
+
+                lda   UserId
+                pha
+
+                pea   #^ToolPath
+                pea   #ToolPath
+                pea   $0001                   ; do not load into special memory
+                pea   $0001                   ; GS/OS string for the argument
+                _InitialLoad2
+                
+                ply
+                pla                           ; Address of the loaded tool
+                plx
+                ply
+                ply
+
+                pea   $8000                   ; User toolset
+                pea   $00A0                   ; Set the tool set number
+                phx
+                pha                           ; Address of function pointer table
+                _SetTSPtr
+
+                clc                           ; Give GTE a page of direct page memory
+                tdc
+                adc   #$0100
+                pha
+                lda   UserId
+                pha
+                _GTEStartUp
+
+                rts
+
+
+MasterId        ds    2
+UserId          ds    2
+ToolPath        strl  '9:GTETool'
\ No newline at end of file
diff --git a/demos/tool/App.s b/demos/tool/App.s
new file mode 100644
index 0000000..3bd4b35
--- /dev/null
+++ b/demos/tool/App.s
@@ -0,0 +1,10 @@
+; IIgs Sprite Testbed
+
+            TYP   $B3                  ; S16 file
+            DSK   GTEToolDemo
+            XPL
+
+; Segment #1 -- Main execution block
+
+            ASM   App.Main.s
+            SNA   Main
diff --git a/demos/tool/GTEToolDemo b/demos/tool/GTEToolDemo
new file mode 100644
index 0000000..466b7a7
Binary files /dev/null and b/demos/tool/GTEToolDemo differ
diff --git a/demos/tool/_FileInformation.txt b/demos/tool/_FileInformation.txt
new file mode 100644
index 0000000..f79c6dd
--- /dev/null
+++ b/demos/tool/_FileInformation.txt
@@ -0,0 +1 @@
+GTEToolDemo=Type(B3),AuxType(0000),VersionCreate(70),MinVersion(BE),Access(E3),FolderInfo1(000000000000000000000000000000000000),FolderInfo2(000000000000000000000000000000000000)
diff --git a/demos/tool/build-image.bat b/demos/tool/build-image.bat
new file mode 100644
index 0000000..5546b72
--- /dev/null
+++ b/demos/tool/build-image.bat
@@ -0,0 +1,19 @@
+echo off
+
+REM Copy all of the assets into the ProDOS image for emulator testing
+REM
+REM Pass the path of the Cadius tool as the first argument (%1)
+
+set CADIUS="%1"
+set IMAGE="..\\..\\emu\\Target.2mg"
+set FOLDER="/GTEDEV/Tool"
+
+REM Cadius does not overwrite files, so clear the root folder first
+%CADIUS% DELETEFOLDER %IMAGE% %FOLDER%
+%CADIUS% CREATEFOLDER %IMAGE% %FOLDER%
+
+REM Now copy files and folders as needed
+%CADIUS% ADDFILE %IMAGE% %FOLDER% .\GTEToolDemo
+%CADIUS% ADDFILE %IMAGE% %FOLDER% ..\..\src\GTETool
+
+REM Copy in the image assets
diff --git a/demos/tool/package.json b/demos/tool/package.json
new file mode 100644
index 0000000..18de1c0
--- /dev/null
+++ b/demos/tool/package.json
@@ -0,0 +1,30 @@
+{
+  "name": "gte-toolbox-demo",
+  "version": "1.0.0",
+  "description": "A testbed for developing a toolbox wrapper around the GTE library",
+  "main": "index.js",
+  "config": {
+    "merlin32": "C:\\Programs\\IIgsXDev\\bin\\Merlin32-1.1.10.exe",
+    "cadius": "C:\\Programs\\IIgsXDev\\bin\\Cadius.exe",
+    "gsport": "C:\\Programs\\gsport\\gsport_0.31\\GSPort.exe",
+    "macros": "../../macros",
+    "crossrunner": "C:\\Programs\\Crossrunner\\Crossrunner.exe"
+  },
+  "scripts": {
+    "test": "npm run build && build-image.bat %npm_package_config_cadius% && %npm_package_config_gsport%",
+    "debug": "%npm_package_config_crossrunner% GTEToolTest -Source GTEToolTest_S02_MAINSEG_Output.txt -Debug -CompatibilityLayer",
+    "build": "%npm_package_config_merlin32% -V %npm_package_config_macros% App.s"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/lscharen/iigs-game-engine.git"
+  },
+  "author": "Lucas Scharenbroich",
+  "license": "Apache-2.0",
+  "bugs": {
+    "url": "https://github.com/lscharen/iigs-game-engine/issues"
+  },
+  "homepage": "https://github.com/lscharen/iigs-game-engine#readme",
+  "devDependencies": {
+  }
+}
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..6391504
--- /dev/null
+++ b/package.json
@@ -0,0 +1,29 @@
+{
+  "name": "generic-tile-engine",
+  "version": "1.0.0",
+  "description": "A tile-base game engine for the Apple IIgs",
+  "main": "index.js",
+  "config": {
+    "merlin32": "C:\\Programs\\IIgsXDev\\bin\\Merlin32-1.1.10.exe",
+    "cadius": "C:\\Programs\\IIgsXDev\\bin\\Cadius.exe",
+    "gsport": "C:\\Programs\\gsport\\gsport_0.31\\GSPort.exe",
+    "macros": "./macros",
+    "crossrunner": "C:\\Programs\\Crossrunner\\Crossrunner.exe"
+  },
+  "scripts": {
+    "test": "npm run build && build-image.bat %npm_package_config_cadius% && %npm_package_config_gsport%",
+    "build": "%npm_package_config_merlin32% -V %npm_package_config_macros% ./src/Master.s"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/lscharen/iigs-game-engine.git"
+  },
+  "author": "Lucas Scharenbroich",
+  "license": "Apache-2.0",
+  "bugs": {
+    "url": "https://github.com/lscharen/iigs-game-engine/issues"
+  },
+  "homepage": "https://github.com/lscharen/iigs-game-engine#readme",
+  "devDependencies": {
+  }
+}
diff --git a/src/Core.s b/src/Core.s
index 3b2a66d..619f4ac 100644
--- a/src/Core.s
+++ b/src/Core.s
@@ -8,94 +8,6 @@
 
                   use       .\Defs.s
 
-; Feature flags
-NO_INTERRUPTS     equ       1                   ; turn off for crossrunner debugging
-NO_MUSIC          equ       1                   ; turn music + tool loading off
-
-; External data space provided by the main program segment
-tiledata          EXT
-TileStore         EXT
-
-; Sprite plane data and mask banks are provided as an exteral segment
-;
-; The sprite data holds a set of pre-rendered sprites that are optimized to support the rendering pipeline.  There
-; are four copies of each sprite, along with the cooresponding mask laid out into 4x4 tile regions where the
-; empty row and column is shared between adjacent blocks.
-;
-; Logically, the memory is laid out as 4 columns of sprites and 4 rows.
-;
-; +---+---+---+---+---+---+---+---+---+---+---+---+-...
-; |   |   |   |   |   |   |   |   |   |   |   |   | ...
-; +---+---+---+---+---+---+---+---+---+---+---+---+-...
-; |   | 0 | 0 |   | 1 | 1 |   | 2 | 2 |   | 3 | 3 | ...
-; +---+---+---+---+---+---+---+---+---+---+---+---+-...
-; |   | 0 | 0 |   | 1 | 1 |   | 2 | 2 |   | 3 | 3 | ...
-; +---+---+---+---+---+---+---+---+---+---+---+---+-...
-; |   |   |   |   |   |   |   |   |   |   |   |   | ...
-; +---+---+---+---+---+---+---+---+---+---+---+---+-...
-; |   | 4 | 4 |   | 5 | 5 |   | 6 | 6 |   | 7 | 7 | ...
-; +---+---+---+---+---+---+---+---+---+---+---+---+-...
-; |   | 4 | 4 |   | 5 | 5 |   | 6 | 6 |   | 7 | 7 | ...
-; +---+---+---+---+---+---+---+---+---+---+---+---+-...
-; |   |   |   |   |   |   |   |   |   |   |   |   | ...
-; +---+---+---+---+---+---+---+---+---+---+---+---+-...
-;
-; For each sprite, when it needs to be copied into an on-screen tile, it could exist at any offset compared to its
-; natural alignment.  By having a buffer around the sprite data, an address pointer can be set to a different origin
-; and a simple 8x8 block copy can cut out the appropriate bit of the sprite.  For example, here is a zoomed-in look
-; at a sprite with an offset, O, at (-2,-3).  As shown, by selecting an appropriate origin, just the top corner
-; of the sprite data will be copied.
-;
-; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
-; |   |           ||           |   ||   |   |   |   ||   |   |   |   |
-; +---+-- O----------------+ --+---++---+---+---+---++---+---+---+---+..
-; |   |   |                |   |   ||   |   |   |   ||   |   |   |   |
-; +---+-- |                | --+---++---+---+---+---++---+---+---+---+..
-; |   |   |                |   |   ||   |   |   |   ||   |   |   |   |
-; +---+-- |                | --+---++---+---+---+---++---+---+---+---+..
-; |   |   |                |   |   ||   |   |   |   ||   |   |   |   |
-; +===+== |       ++===+== | ==+===++===+===+===+===++===+===+===+===+..
-; |   |   |       ||   | S | S | S || S | S | S |   ||   |   |   |   |
-; +---+-- +----------------+ --+---++---+---+---+---++---+---+---+---+..
-; |   |           || S | S   S | S || S | S | S | S ||   |   |   |   |
-; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
-; |   |   |   |   || S | S | S | S || S | S | S | S ||   |   |   |   |
-; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
-; |   |   |   |   || S | S | S | S || S | S | S | S ||   |   |   |   |
-; +===+===+===+===++===+===+===+===++===+===+===+===++===+===+===+===+..
-; |   |   |   |   || S | S | S | S || S | S | S | S ||   |   |   |   |
-; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
-; |   |   |   |   || S | S | S | S || S | S | S | S ||   |   |   |   |
-; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
-; |   |   |   |   || S | S | S | S || S | S | S | S ||   |   |   |   |
-; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
-; |   |   |   |   ||   | S | S | S || S | S | S |   ||   |   |   |   |
-; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
-; .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .
-;
-; Each sprite will take up, effectively 9 tiles of storage space per 
-; instance (plus edges) and there are 4 instances for the H/V bits
-; and 4 more for the masks.  This results in a need for 43,264 bytes
-; for all 16 sprites.
-
-spritedata        EXT
-spritemask        EXT
-
-; If there are overlays, they are provided as an external
-Overlay           EXT
-
-; Core engine functionality.  The idea is that that source file can be PUT into
-; a main source file and all of the functionality will be available.
-;
-; There are some constancts that must be externally defined that can affect how
-; the GTE runtime works
-;
-; NO_MUSIC      : Set to non-zero to avoid using any source
-; NO_INTERRUPTS : Set to non-zero to avoid installing custom interrupt handlers
-
-                  mx        %00
-
-; High-Level StartUp and ShutDown functions
 EngineStartUp     ENT
                   phb
                   phk
@@ -103,41 +15,23 @@ EngineStartUp     ENT
 
                   jsr       ToolStartUp         ; Start up the toolbox tools we rely on
                   jsr       _CoreStartUp
+                  jsr       SoundStartUp        ; Start up any sound/music tools
 
                   plb
                   rtl
 
-_CoreStartUp
-                  jsr       SoundStartUp        ; Start up any sound/music tools
-                  jsr       IntStartUp          ; Enable certain iterrupts
-
-                  jsr       InitMemory          ; Allocate and initialize memory for the engine
-                  jsr       EngineReset         ; All of the resources are allocated, put the engine in a known state
-
-                  jsr       InitGraphics        ; Initialize all of the graphics-related data
-                  nop
-                  jsr       InitSprites         ; Initialize the sprite subsystem
-                  jsr       InitTiles           ; Initialize the tile subsystem
-
-                  jsr       InitTimers          ; Initialize the timer subsystem
-                  rts
-
 EngineShutDown    ENT
                   phb
                   phk
                   plb
 
+                  jsr       SoundShutDown
                   jsr       _CoreShutDown
                   jsr       ToolShutDown
 
                   plb
                   rtl
 
-_CoreShutDown
-                  jsr       IntShutDown
-                  jsr       SoundShutDown
-                  rts
-
 ToolStartUp
                   _TLStartUp                    ; normal tool initialization
                   pha
@@ -152,7 +46,7 @@ ToolStartUp
                   rts
 
 MasterId          ds        2
-UserId            ds        2
+;UserId            ds        2
 
 ; Fatal error handler invoked by the _Err macro
 PgmDeath          tax
@@ -168,9 +62,6 @@ PgmDeath0         pha
 ContDeath         ldx       #$1503
                   jsl       $E10000
 
-ToolShutDown
-                  rts
-
 ; Use Tool222 (NinjaTrackerPlus) for music playback
 SoundStartUp
                   lda       #NO_MUSIC
@@ -194,299 +85,10 @@ SoundShutDown
 :no_music
                   rts
 
-; Install interrupt handlers.  We use the VBL interrupt to keep animations
-; moving at a consistent rate, regarless of the rendered frame rate.  The 
-; one-second timer is generally just used for counters and as a handy 
-; frames-per-second trigger.
-IntStartUp
-                  lda       #NO_INTERRUPTS
-                  bne       :no_interrupts
-                  PushLong  #0
-                  pea       $0015               ; Get the existing 1-second interrupt handler and save
-                  _GetVector
-                  PullLong  OldOneSecVec
-
-                  pea       $0015               ; Set the new handler and enable interrupts
-                  PushLong  #OneSecHandler
-                  _SetVector
-
-                  pea       $0006
-                  _IntSource
-
-                  PushLong  #VBLTASK            ; Also register a Heart Beat Task
-                  _SetHeartBeat
-
-:no_interrupts
-                  rts
-
-IntShutDown
-                  lda       #NO_INTERRUPTS
-                  bne       :no_interrupts
-
-                  pea       $0007               ; disable 1-second interrupts
-                  _IntSource
-
-                  PushLong  #VBLTASK            ; Remove our heartbeat task
-                  _DelHeartBeat
-
-                  pea       $0015
-                  PushLong  OldOneSecVec        ; Reset the interrupt vector
-                  _SetVector
-
-:no_interrupts
-                  rts
-
-
-; Interrupt handlers. We install a heartbeat (1/60th second and a 1-second timer)
-OneSecHandler     mx        %11
-                  phb
-                  pha
-                  phk
-                  plb
-
-                  rep       #$20
-                  inc       OneSecondCounter
-                  sep       #$20
-
-                  ldal      $E0C032
-                  and       #%10111111          ;clear IRQ source
-                  stal      $E0C032
-
-                  pla
-                  plb
-                  clc
-                  rtl
-                  mx        %00
-
-OneSecondCounter  ENT
-                  dw        0
-OldOneSecVec      ds        4
-
-VBLTASK           hex       00000000
-                  dw        0
-                  hex       5AA5
-
-; Reset the engine to a known state
-; Blitter initialization
-EngineReset
-                  stz       ScreenHeight
-                  stz       ScreenWidth
-                  stz       ScreenY0
-                  stz       ScreenY1
-                  stz       ScreenX0
-                  stz       ScreenX1
-                  stz       ScreenTileHeight
-                  stz       ScreenTileWidth
-                  stz       StartX
-                  stz       OldStartX
-                  stz       StartXMod164
-
-                  stz       StartY
-                  stz       OldStartY
-                  stz       StartYMod208
-
-                  stz       EngineMode
-                  stz       DirtyBits
-                  stz       LastRender
-                  stz       LastPatchOffset
-                  stz       BG1StartX
-                  stz       BG1StartXMod164
-                  stz       BG1StartY
-                  stz       BG1StartYMod208
-                  stz       BG1OffsetIndex
-
-                  stz       BG0TileOriginX
-                  stz       BG0TileOriginY
-                  stz       OldBG0TileOriginX
-                  stz       OldBG0TileOriginY
-
-                  stz       BG1TileOriginX
-                  stz       BG1TileOriginY
-                  stz       OldBG1TileOriginX
-                  stz       OldBG1TileOriginY
-
-                  stz       TileMapWidth
-                  stz       TileMapHeight
-                  stz       TileMapPtr
-                  stz       TileMapPtr+2
-                  stz       FringeMapPtr
-                  stz       FringeMapPtr+2
-
-                  stz       BG1TileMapWidth
-                  stz       BG1TileMapHeight
-                  stz       BG1TileMapPtr
-                  stz       BG1TileMapPtr+2
-
-                  stz       SCBArrayPtr
-                  stz       SCBArrayPtr+2
-
-                  stz       SpriteBanks
-                  stz       SpriteMap
-                  stz       ActiveSpriteCount
-
-                  stz       OneSecondCounter
-
-                  lda       #13
-                  sta       tmp15
-                  stz       tmp14
-
-:loop
-                  ldx       #BlitBuff
-                  lda       #^BlitBuff
-                  ldy       tmp14
-                  jsr       BuildBank
-
-                  lda       tmp14
-                  clc
-                  adc       #4
-                  sta       tmp14
-
-                  dec       tmp15
-                  bne       :loop
-
-                  rts
-
-; Allow the user to dynamically select one of the pre-configured screen sizes, or pass
-; in a specific width and height.  The screen is automatically centered.  If this is
-; not desired, then SetScreenRect should be used directly
-;
-;  0. Full Screen           : 40 x 25   320 x 200 (32,000 bytes (100.0%)) 
-;  1. Sword of Sodan        : 34 x 24   272 x 192 (26,112 bytes ( 81.6%))
-;  2. ~NES                  : 32 x 25   256 x 200 (25,600 bytes ( 80.0%))
-;  3. Task Force            : 32 x 22   256 x 176 (22,528 bytes ( 70.4%))
-;  4. Defender of the World : 35 x 20   280 x 160 (22,400 bytes ( 70.0%))
-;  5. Rastan                : 32 x 20   256 x 160 (20,480 bytes ( 64.0%))
-;  6. Game Boy Advanced     : 30 x 20   240 x 160 (19,200 bytes ( 60.0%))
-;  7. Ancient Land of Y's   : 36 x 16   288 x 128 (18,432 bytes ( 57.6%))
-;  8. Game Boy Color        : 20 x 18   160 x 144 (11,520 bytes ( 36.0%))
-;  9. Agony (Amiga)         : 36 x 24   288 x 192 (27,648 bytes ( 86.4%))
-; 10. Atari Lynx            : 20 x 13   160 x 102 (8,160 bytes  ( 25.5%))
-;
-;  X = mode number OR width in pixels (must be multiple of 2)
-;  Y = height in pixels (if X > 8)
-
-ScreenModeWidth   dw        320,272,256,256,280,256,240,288,160,288,160,320
-ScreenModeHeight  dw        200,192,200,176,160,160,160,128,144,192,102,1
-
-SetScreenMode     ENT
-                  phb
-                  phk
-                  plb
-                  jsr       _SetScreenMode
-                  plb
-                  rtl
-
-_SetScreenMode
-                  cpx       #11
-                  bcs       :direct             ; if x > 10, then assume X and Y are the dimensions
-
-                  txa
-                  asl
-                  tax
-
-                  ldy       ScreenModeHeight,x
-                  lda       ScreenModeWidth,x
-                  tax
-
-:direct           cpy       #201
-                  bcs       :exit
-
-                  cpx       #321
-                  bcs       :exit
-
-                  txa
-                  lsr
-                  pha                           ; Save X (width / 2) and Y (height)
-                  phy
-
-                  lda       #160                ; Center the screen
-                  sec
-                  sbc       3,s
-                  lsr
-                  xba
-                  pha                           ; Save half the origin coordinate
-
-                  lda       #200
-                  sec
-                  sbc       3,s                 ; This is now Y because of the PHA above
-                  lsr
-                  ora       1,s
-
-                  plx                           ; Throw-away to pop the stack
-                  ply
-                  plx
-
-                  jsr       SetScreenRect
-                  jmp       FillScreen          ; tail return
-:exit
-                  rts
-
-
-WaitForKey        sep       #$20
-                  stal      KBD_STROBE_REG      ; clear the strobe
-:WFK              ldal      KBD_REG
-                  bpl       :WFK
-                  rep       #$20
-                  and       #$007F
-                  rts
-
-ClearKbdStrobe    sep       #$20
-                  stal      KBD_STROBE_REG
-                  rep       #$20
-                  rts
-
-; Read the keyboard and paddle controls and return in a game-controller-like format
-LastKey           db        0
-ReadControl       ENT
-                  jsr       _ReadControl
-                  rtl
-
-_ReadControl      
-                  pea       $0000               ; low byte = key code, high byte = %------AB 
-
-                  sep       #$20
-                  ldal      OPTION_KEY_REG      ; 'B' button
-                  and       #$80
-                  beq       :BNotDown
-
-                  lda       #PAD_BUTTON_B
-                  ora       2,s
-                  sta       2,s
-
-:BNotDown
-                  ldal      COMMAND_KEY_REG
-                  and       #$80
-                  beq       :ANotDown
-
-                  lda       #PAD_BUTTON_A
-                  ora       2,s
-                  sta       2,s
-
-:ANotDown
-                  ldal      KBD_STROBE_REG      ; read the keyboard
-                  bit       #$80
-                  beq       :KbdNotDwn          ; check the key-down status
-                  and       #$7f
-                  ora       1,s
-                  sta       1,s
-
-                  cmpl      LastKey
-                  beq       :KbdDown
-                  stal      LastKey
-
-                  lda       #PAD_KEY_DOWN       ; set the keydown flag
-                  ora       2,s
-                  sta       2,s
-                  bra       :KbdDown
-
-:KbdNotDwn
-                  lda       #0
-                  stal      LastKey
-:KbdDown
-                  rep       #$20
-                  pla
+ToolShutDown
                   rts
 
+                  put       CoreImpl.s
                   put       blitter/Template.s
 
                   put       Memory.s
diff --git a/src/CoreImpl.s b/src/CoreImpl.s
new file mode 100644
index 0000000..b4708ed
--- /dev/null
+++ b/src/CoreImpl.s
@@ -0,0 +1,369 @@
+; Feature flags
+NO_INTERRUPTS     equ       1                   ; turn off for crossrunner debugging
+NO_MUSIC          equ       1                   ; turn music + tool loading off
+
+; External data space provided by the main program segment
+tiledata          EXT
+TileStore         EXT
+
+; Sprite plane data and mask banks are provided as an external segment
+;
+; The sprite data holds a set of pre-rendered sprites that are optimized to support the rendering pipeline.  There
+; are four copies of each sprite, along with the cooresponding mask laid out into 4x4 tile regions where the
+; empty row and column is shared between adjacent blocks.
+;
+; Logically, the memory is laid out as 4 columns of sprites and 4 rows.
+;
+; +---+---+---+---+---+---+---+---+---+---+---+---+-...
+; |   |   |   |   |   |   |   |   |   |   |   |   | ...
+; +---+---+---+---+---+---+---+---+---+---+---+---+-...
+; |   | 0 | 0 |   | 1 | 1 |   | 2 | 2 |   | 3 | 3 | ...
+; +---+---+---+---+---+---+---+---+---+---+---+---+-...
+; |   | 0 | 0 |   | 1 | 1 |   | 2 | 2 |   | 3 | 3 | ...
+; +---+---+---+---+---+---+---+---+---+---+---+---+-...
+; |   |   |   |   |   |   |   |   |   |   |   |   | ...
+; +---+---+---+---+---+---+---+---+---+---+---+---+-...
+; |   | 4 | 4 |   | 5 | 5 |   | 6 | 6 |   | 7 | 7 | ...
+; +---+---+---+---+---+---+---+---+---+---+---+---+-...
+; |   | 4 | 4 |   | 5 | 5 |   | 6 | 6 |   | 7 | 7 | ...
+; +---+---+---+---+---+---+---+---+---+---+---+---+-...
+; |   |   |   |   |   |   |   |   |   |   |   |   | ...
+; +---+---+---+---+---+---+---+---+---+---+---+---+-...
+;
+; For each sprite, when it needs to be copied into an on-screen tile, it could exist at any offset compared to its
+; natural alignment.  By having a buffer around the sprite data, an address pointer can be set to a different origin
+; and a simple 8x8 block copy can cut out the appropriate bit of the sprite.  For example, here is a zoomed-in look
+; at a sprite with an offset, O, at (-2,-3).  As shown, by selecting an appropriate origin, just the top corner
+; of the sprite data will be copied.
+;
+; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
+; |   |           ||           |   ||   |   |   |   ||   |   |   |   |
+; +---+-- O----------------+ --+---++---+---+---+---++---+---+---+---+..
+; |   |   |                |   |   ||   |   |   |   ||   |   |   |   |
+; +---+-- |                | --+---++---+---+---+---++---+---+---+---+..
+; |   |   |                |   |   ||   |   |   |   ||   |   |   |   |
+; +---+-- |                | --+---++---+---+---+---++---+---+---+---+..
+; |   |   |                |   |   ||   |   |   |   ||   |   |   |   |
+; +===+== |       ++===+== | ==+===++===+===+===+===++===+===+===+===+..
+; |   |   |       ||   | S | S | S || S | S | S |   ||   |   |   |   |
+; +---+-- +----------------+ --+---++---+---+---+---++---+---+---+---+..
+; |   |           || S | S   S | S || S | S | S | S ||   |   |   |   |
+; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
+; |   |   |   |   || S | S | S | S || S | S | S | S ||   |   |   |   |
+; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
+; |   |   |   |   || S | S | S | S || S | S | S | S ||   |   |   |   |
+; +===+===+===+===++===+===+===+===++===+===+===+===++===+===+===+===+..
+; |   |   |   |   || S | S | S | S || S | S | S | S ||   |   |   |   |
+; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
+; |   |   |   |   || S | S | S | S || S | S | S | S ||   |   |   |   |
+; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
+; |   |   |   |   || S | S | S | S || S | S | S | S ||   |   |   |   |
+; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
+; |   |   |   |   ||   | S | S | S || S | S | S |   ||   |   |   |   |
+; +---+---+---+---++---+---+---+---++---+---+---+---++---+---+---+---+..
+; .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .   .
+;
+; Each sprite will take up, effectively 9 tiles of storage space per 
+; instance (plus edges) and there are 4 instances for the H/V bits
+; and 4 more for the masks.  This results in a need for 43,264 bytes
+; for all 16 sprites.
+
+spritedata        EXT
+spritemask        EXT
+
+; If there are overlays, they are provided as an external
+Overlay           EXT
+
+; Core engine functionality.  The idea is that that source file can be PUT into
+; a main source file and all of the functionality will be available.
+;
+; There are some constancts that must be externally defined that can affect how
+; the GTE runtime works
+;
+; NO_MUSIC      : Set to non-zero to avoid using any source
+; NO_INTERRUPTS : Set to non-zero to avoid installing custom interrupt handlers
+
+                  mx        %00
+
+; A = memory manager userId
+; X = tool number
+_CoreStartUp
+                  sta       UserId              ; This is the first thing to do
+                  stx       ToolNum
+
+                  jsr       IntStartUp          ; Enable certain iterrupts
+
+                  jsr       InitMemory          ; Allocate and initialize memory for the engine
+                  jsr       EngineReset         ; All of the resources are allocated, put the engine in a known state
+
+;                  jsr       InitGraphics        ; Initialize all of the graphics-related data
+;                  jsr       InitSprites         ; Initialize the sprite subsystem
+;                  jsr       InitTiles           ; Initialize the tile subsystem
+
+                  jsr       InitTimers          ; Initialize the timer subsystem
+
+_CoreShutDown
+                  jsr       IntShutDown
+                  rts
+
+; Install interrupt handlers.  We use the VBL interrupt to keep animations
+; moving at a consistent rate, regarless of the rendered frame rate.  The 
+; one-second timer is generally just used for counters and as a handy 
+; frames-per-second trigger.
+IntStartUp
+                  lda       #NO_INTERRUPTS
+                  bne       :no_interrupts
+                  PushLong  #0
+                  pea       $0015               ; Get the existing 1-second interrupt handler and save
+                  _GetVector
+                  PullLong  OldOneSecVec
+
+                  pea       $0015               ; Set the new handler and enable interrupts
+                  PushLong  #OneSecHandler
+                  _SetVector
+
+                  pea       $0006
+                  _IntSource
+
+                  PushLong  #VBLTASK            ; Also register a Heart Beat Task
+                  _SetHeartBeat
+
+:no_interrupts
+                  rts
+
+IntShutDown
+                  lda       #NO_INTERRUPTS
+                  bne       :no_interrupts
+
+                  pea       $0007               ; disable 1-second interrupts
+                  _IntSource
+
+                  PushLong  #VBLTASK            ; Remove our heartbeat task
+                  _DelHeartBeat
+
+                  pea       $0015
+                  PushLong  OldOneSecVec        ; Reset the interrupt vector
+                  _SetVector
+
+:no_interrupts
+                  rts
+
+
+; Interrupt handlers. We install a heartbeat (1/60th second and a 1-second timer)
+OneSecHandler     mx        %11
+                  phb
+                  pha
+                  phk
+                  plb
+
+                  rep       #$20
+                  inc       OneSecondCounter
+                  sep       #$20
+
+                  ldal      $E0C032
+                  and       #%10111111          ;clear IRQ source
+                  stal      $E0C032
+
+                  pla
+                  plb
+                  clc
+                  rtl
+                  mx        %00
+
+OneSecondCounter  ENT
+                  dw        0
+OldOneSecVec      ds        4
+
+VBLTASK           hex       00000000
+                  dw        0
+                  hex       5AA5
+
+; Reset the engine to a known state
+; Blitter initialization
+EngineReset
+                  stz       ScreenHeight
+                  stz       ScreenWidth
+                  stz       ScreenY0
+                  stz       ScreenY1
+                  stz       ScreenX0
+                  stz       ScreenX1
+                  stz       ScreenTileHeight
+                  stz       ScreenTileWidth
+                  stz       StartX
+                  stz       OldStartX
+                  stz       StartXMod164
+
+                  stz       StartY
+                  stz       OldStartY
+                  stz       StartYMod208
+
+                  stz       EngineMode
+                  stz       DirtyBits
+                  stz       LastRender
+                  stz       LastPatchOffset
+                  stz       BG1StartX
+                  stz       BG1StartXMod164
+                  stz       BG1StartY
+                  stz       BG1StartYMod208
+                  stz       BG1OffsetIndex
+
+                  stz       BG0TileOriginX
+                  stz       BG0TileOriginY
+                  stz       OldBG0TileOriginX
+                  stz       OldBG0TileOriginY
+
+                  stz       BG1TileOriginX
+                  stz       BG1TileOriginY
+                  stz       OldBG1TileOriginX
+                  stz       OldBG1TileOriginY
+
+                  stz       TileMapWidth
+                  stz       TileMapHeight
+                  stz       TileMapPtr
+                  stz       TileMapPtr+2
+                  stz       FringeMapPtr
+                  stz       FringeMapPtr+2
+
+                  stz       BG1TileMapWidth
+                  stz       BG1TileMapHeight
+                  stz       BG1TileMapPtr
+                  stz       BG1TileMapPtr+2
+
+                  stz       SCBArrayPtr
+                  stz       SCBArrayPtr+2
+
+                  stz       SpriteBanks
+                  stz       SpriteMap
+                  stz       ActiveSpriteCount
+
+                  stz       OneSecondCounter
+
+                  lda       #13
+                  sta       tmp15
+                  stz       tmp14
+
+:loop
+                  ldx       #BlitBuff
+                  lda       #^BlitBuff
+                  ldy       tmp14
+;                  jsr       BuildBank
+
+                  lda       tmp14
+                  clc
+                  adc       #4
+                  sta       tmp14
+
+                  dec       tmp15
+                  bne       :loop
+
+                  rts
+
+
+WaitForKey        sep       #$20
+                  stal      KBD_STROBE_REG      ; clear the strobe
+:WFK              ldal      KBD_REG
+                  bpl       :WFK
+                  rep       #$20
+                  and       #$007F
+                  rts
+
+ClearKbdStrobe    sep       #$20
+                  stal      KBD_STROBE_REG
+                  rep       #$20
+                  rts
+
+; Read the keyboard and paddle controls and return in a game-controller-like format
+LastKey           db        0
+ReadControl       ENT
+                  jsr       _ReadControl
+                  rtl
+
+_ReadControl      
+                  pea       $0000               ; low byte = key code, high byte = %------AB 
+
+                  sep       #$20
+                  ldal      OPTION_KEY_REG      ; 'B' button
+                  and       #$80
+                  beq       :BNotDown
+
+                  lda       #PAD_BUTTON_B
+                  ora       2,s
+                  sta       2,s
+
+:BNotDown
+                  ldal      COMMAND_KEY_REG
+                  and       #$80
+                  beq       :ANotDown
+
+                  lda       #PAD_BUTTON_A
+                  ora       2,s
+                  sta       2,s
+
+:ANotDown
+                  ldal      KBD_STROBE_REG      ; read the keyboard
+                  bit       #$80
+                  beq       :KbdNotDwn          ; check the key-down status
+                  and       #$7f
+                  ora       1,s
+                  sta       1,s
+
+                  cmpl      LastKey
+                  beq       :KbdDown
+                  stal      LastKey
+
+                  lda       #PAD_KEY_DOWN       ; set the keydown flag
+                  ora       2,s
+                  sta       2,s
+                  bra       :KbdDown
+
+:KbdNotDwn
+                  lda       #0
+                  stal      LastKey
+:KbdDown
+                  rep       #$20
+                  pla
+                  rts
+
+
+; Helper function to take a local pixel coordinate [0, ScreenWidth-1],[0, ScreenHeight-1] and return the
+; row and column in the tile store that is corresponds to.  This takes into consideration the StartX and
+; StartY offsets.
+;
+; This is more specialized than the code in the _MarkDirtySprite routine below since it does not deal with
+; negative or off-screen values.
+_OriginToTileStore
+        lda   StartYMod208
+        lsr
+        lsr
+        and   #$FFFE                             ; Store the pre-multiplied by 2 for indexing
+        tay
+        lda   StartXMod164
+        lsr
+        and   #$FFFE                             ; Same pre-multiply by 2 for later
+        tax
+        rts
+
+; X = local x-coordinate (0, playfield width)
+; Y = local y-coordinate (0, playfield height)
+_LocalToTileStore
+        clc
+        tya
+        adc   StartYMod208                       ; Adjust for the scroll offset
+        cmp   #208                               ; check if we went too far positive
+        bcc   *+5
+        sbc   #208
+        lsr
+        lsr
+        and   #$FFFE                             ; Store the pre-multiplied by 2 for indexing
+        tay
+
+        clc
+        txa
+        adc   StartXMod164
+        cmp   #164
+        bcc   *+5
+        sbc   #164
+        lsr
+        and   #$FFFE                             ; Same pre-multiply by 2 for later
+        tax
+        rts
\ No newline at end of file
diff --git a/src/Defs.s b/src/Defs.s
index d2d8017..2f5e12c 100644
--- a/src/Defs.s
+++ b/src/Defs.s
@@ -88,7 +88,9 @@ BankLoad               equ   104
 TileStoreBankAndBank01 equ   106
 TileStoreBankAndTileDataBank equ 108
 TileStoreBankDoubled   equ   110
-Next                   equ   112
+UserId                 equ   112         ; Memory manager user Id to use
+ToolNum                equ   114         ; Tool number assigned to us
+Next                   equ   116
 
 activeSpriteList       equ   128         ; 32 bytes for the active sprite list (can persist across frames)
 ; tiletmp                equ   178         ; 16 bytes of temp storage for the tile renderers
diff --git a/src/Graphics.s b/src/Graphics.s
index 5fe5f94..1ef1656 100644
--- a/src/Graphics.s
+++ b/src/Graphics.s
@@ -24,6 +24,82 @@ DefaultPalette   dw    $0000,$007F,$0090,$0FF0
                  dw    $0fa9,$0ff0,$00e0,$04DF
                  dw    $0d00,$078f,$0ccc,$0FFF
 
+
+; Allow the user to dynamically select one of the pre-configured screen sizes, or pass
+; in a specific width and height.  The screen is automatically centered.  If this is
+; not desired, then SetScreenRect should be used directly
+;
+;  0. Full Screen           : 40 x 25   320 x 200 (32,000 bytes (100.0%)) 
+;  1. Sword of Sodan        : 34 x 24   272 x 192 (26,112 bytes ( 81.6%))
+;  2. ~NES                  : 32 x 25   256 x 200 (25,600 bytes ( 80.0%))
+;  3. Task Force            : 32 x 22   256 x 176 (22,528 bytes ( 70.4%))
+;  4. Defender of the World : 35 x 20   280 x 160 (22,400 bytes ( 70.0%))
+;  5. Rastan                : 32 x 20   256 x 160 (20,480 bytes ( 64.0%))
+;  6. Game Boy Advanced     : 30 x 20   240 x 160 (19,200 bytes ( 60.0%))
+;  7. Ancient Land of Y's   : 36 x 16   288 x 128 (18,432 bytes ( 57.6%))
+;  8. Game Boy Color        : 20 x 18   160 x 144 (11,520 bytes ( 36.0%))
+;  9. Agony (Amiga)         : 36 x 24   288 x 192 (27,648 bytes ( 86.4%))
+; 10. Atari Lynx            : 20 x 13   160 x 102 (8,160 bytes  ( 25.5%))
+;
+;  X = mode number OR width in pixels (must be multiple of 2)
+;  Y = height in pixels (if X > 8)
+
+ScreenModeWidth   dw        320,272,256,256,280,256,240,288,160,288,160,320
+ScreenModeHeight  dw        200,192,200,176,160,160,160,128,144,192,102,1
+
+SetScreenMode     ENT
+                  phb
+                  phk
+                  plb
+                  jsr       _SetScreenMode
+                  plb
+                  rtl
+
+_SetScreenMode
+                  cpx       #11
+                  bcs       :direct             ; if x > 10, then assume X and Y are the dimensions
+
+                  txa
+                  asl
+                  tax
+
+                  ldy       ScreenModeHeight,x
+                  lda       ScreenModeWidth,x
+                  tax
+
+:direct           cpy       #201
+                  bcs       :exit
+
+                  cpx       #321
+                  bcs       :exit
+
+                  txa
+                  lsr
+                  pha                           ; Save X (width / 2) and Y (height)
+                  phy
+
+                  lda       #160                ; Center the screen
+                  sec
+                  sbc       3,s
+                  lsr
+                  xba
+                  pha                           ; Save half the origin coordinate
+
+                  lda       #200
+                  sec
+                  sbc       3,s                 ; This is now Y because of the PHA above
+                  lsr
+                  ora       1,s
+
+                  plx                           ; Throw-away to pop the stack
+                  ply
+                  plx
+
+                  jsr       SetScreenRect
+                  jmp       FillScreen          ; tail return
+:exit
+                  rts
+
 ; Return the current border color ($0 - $F) in the accumulator
 _GetBorderColor  lda   #0000
                  sep   #$20
diff --git a/src/Master.s b/src/Master.s
new file mode 100644
index 0000000..223034c
--- /dev/null
+++ b/src/Master.s
@@ -0,0 +1,34 @@
+; IIgs Generic Tile Engine User Toolset
+
+            TYP   $BA                  ; TOL file
+            DSK   GTETool
+            XPL
+
+; Main toolbox interface and code
+
+            ASM   Tool.s
+            SNA   Main
+
+; 64KB Tile Memory
+
+            ASM   static\TileData.s
+            KND   #$1001               ; Type and Attributes ($10=Static,$01=Data)
+            SNA   TDATA
+
+; 64KB Sprite Plane Data
+
+            ASM   static\SprData.s
+            KND   #$1001               ; Type and Attributes ($11=Static+Bank Relative,$01=Data)
+            SNA   SDATA
+
+;64KB Sprite Mask Data
+
+            ASM   static\SprMask.s
+            KND   #$1001               ; Type and Attributes ($11=Static+Bank Relative,$01=Data)
+            SNA   SMASK
+
+; 64KB Tile Store
+
+            ASM   static\TileStore.s
+            KND   #$1001               ; Type and Attributes ($11=Static+Bank Relative,$01=Data)
+            SNA   TSTORE
diff --git a/src/Sprite.s b/src/Sprite.s
index a3bcb89..b659ed8 100644
--- a/src/Sprite.s
+++ b/src/Sprite.s
@@ -62,9 +62,9 @@ InitSprites
 ; covering the exact same tiles.
 
 
-; Render a sprite stamp into the sprite buffer.  Stamps exits independent of the sprites
+; Render a sprite stamp into the sprite buffer.  Stamps exist independent of the sprites
 ; and sprite reference a specific stamp.  This is necessary because it's common for a
-; spite to change its graphic as its animating, but it is too costly to have to set up
+; sprite to change its graphic as its animating, but it is too costly to have to set up
 ; the stamp every time.  So this allows users to create stamps in advance and then
 ; assign them to the sprites as needed.
 ;
diff --git a/src/Sprite2.s b/src/Sprite2.s
index 9d83bea..404ade4 100644
--- a/src/Sprite2.s
+++ b/src/Sprite2.s
@@ -16,49 +16,6 @@ ColLeft     equ   tmp9
 SpriteBit   equ   tmp10     ; set the bit of the value that if the current sprite index
 VBuffOrigin equ   tmp11
 
-; Helper function to take a local pixel coordinate [0, ScreenWidth-1],[0, ScreenHeight-1] and return the
-; row and column in the tile store that is corresponds to.  This takes into consideration the StartX and
-; StartY offsets.
-;
-; This is more specialized than the code in the _MarkDirtySprite routine below since it does not deal with
-; negative or off-screen values.
-_OriginToTileStore
-        lda   StartYMod208
-        lsr
-        lsr
-        and   #$FFFE                             ; Store the pre-multiplied by 2 for indexing
-        tay
-        lda   StartXMod164
-        lsr
-        and   #$FFFE                             ; Same pre-multiply by 2 for later
-        tax
-        rts
-
-; X = local x-coordinate (0, playfield width)
-; Y = local y-coordinate (0, playfield height)
-_LocalToTileStore
-        clc
-        tya
-        adc   StartYMod208                       ; Adjust for the scroll offset
-        cmp   #208                               ; check if we went too far positive
-        bcc   *+5
-        sbc   #208
-        lsr
-        lsr
-        and   #$FFFE                             ; Store the pre-multiplied by 2 for indexing
-        tay
-
-        clc
-        txa
-        adc   StartXMod164
-        cmp   #164
-        bcc   *+5
-        sbc   #164
-        lsr
-        and   #$FFFE                             ; Same pre-multiply by 2 for later
-        tax
-        rts
-
 ; Marks a sprite as dirty.  The work here is mapping from local screen coordinates to the 
 ; tile store indices.  The first step is to adjust the sprite coordinates based on the current
 ; code field offsets and then cache variations of this value needed in the rest of the subroutine
diff --git a/src/Tool.s b/src/Tool.s
index c1ba0dd..2fdf11e 100644
--- a/src/Tool.s
+++ b/src/Tool.s
@@ -3,10 +3,19 @@
 ; Ref: Toolbox Reference, Volume 2, Appendix A
 ; Ref: IIgs Tech Note #73
 
+;                  use       Load.Macs.s
+                use   Mem.Macs.s
+                use   Misc.Macs.s
+                use   Util.Macs
+                use   Locator.Macs
+                use   Core.MACS.s
+
+                use   Defs.s
+
 ToStrip         equ   $E10184
 
 _CallTable
-                dw    {_CTEnd-_CallTable}/4,0
+                adrl  {_CTEnd-_CallTable}/4
                 adrl  _TSBootInit-1
                 adrl  _TSStartUp-1
                 adrl  _TSShutDown-1
@@ -25,40 +34,58 @@ _TSBootInit
                 clc
                 rtl
 
-; Call the regular GTE startup function after setting the Work Area Point (WAP).  The caller much provide
-; one page of Bank 0 memory for the tool set's private use
+; Call the regular GTE startup function after setting the Work Area Pointer (WAP).  The caller must provide
+; one page of Bank 0 memory for the tool set's private use and a userId to use for allocating memory
 ;
-; X = 
+; X = tool set number in low byte and function umber in high byte
+;
+; StartUp(dPageAddr, userId)
 _TSStartUp
-:zpToUse        equ     7
 
-                pea     #$8000
+rtll            =    1
+rtl2            =    rtl1+3
+userId          =    7
+zpToUse         =    userId+2
+
                 txa
-                and     #$00FF
-                pha
+                and     #$00FF                ; Get just the tool number
+                tax
 
-                pea     $0000
-                lda     :zpToUse+6,s
-                pha
+                lda     userId,s              ; Get the userId for memory allocations
+                tay
+                lda     zpToUse,s             ; Get the direct page address
+
+                phd                           ; Save the current direct page
+                tcd                           ; Set to our working direct page space
+
+                tya                           ; A = memory manager user Id, X = tool number
+                jsr     _CoreStartUp          ; Initialize the library
+
+; SetWAP(userOrSystem, tsNum, waptPtr)
+
+                pea     #$8000                ; $8000 = user tool set
+                pei     ToolNum               ; Push the tool number from the direct page
+                pea     $0000                 ; High word of WAP is zero (bank 0)
+                phd                           ; Low word of WAP is the direct page
                 _SetWAP
 
-                jsr     _CoreStartUp
+                pld                           ; Restore the caller's direct page
+
+                lda     #0
+                clc
+                rtl
 
 _TSShutDown
                 cmp     #0                 ; Acc is low word of the WAP (direct page)
                 beq     :inactive
 
                 phd
-                pha
-                pld                        ; Set the direct page for the toolset
+                tcd                        ; Set the direct page for the toolset
 
-                phx                        ; Preserve the X register
-                jsr     _CoreShutDown      ; Shut down GTE
-                pla
+                jsr     _CoreShutDown      ; Shut down the library
 
                 pea     $8000
-                and     #$00FF
-                pha
+                pei     ToolNum
                 pea     $0000              ; Set WAP to null
                 pea     $0000
                 _SetWAP
@@ -71,7 +98,7 @@ _TSShutDown
                 rtl
 
 _TSVersion
-                lda     #$0100     ; Version 1
+                lda     #$0100             ; Version 1
                 sta     7,s
 
                 lda     #0
@@ -101,31 +128,45 @@ _TSReserved
                 sec
                 rtl
 
+; SetScreenMode(width, height)
 _TSSetScreenMode
-                phd                       ; Preserve the direct page
-                pha
-                pld
+:height         equ     9
+:width          equ     11
 
-                lda     9,s
+                phd                       ; Preserve the direct page
+                tcd                       ; Set the tool set direct pafe from WAP
+
+                lda     :height,s
                 tay
-                lda     9,s
+                lda     :width,s
                 tax
-                jsr     _SetScreenMode
-                pld
+;                jsr     _SetScreenMode   ; Not implemented yet
+
+                pld                       ; Restore direct page
 
                 ldx     #0                 ; No error
                 ldy     #4                 ; Remove the 4 input bytes
                 jml     ToStrip
 
 _TSReadControl
+:output         equ     9
+
                 phd                       ; Preserve the direct page
-                pha
-                pld
+                tcd
 
                 jsr     _ReadControl
-                sta     9,s
+                sta     :output,s
 
                 pld
                 ldx     #0                 ; No error
                 ldy     #0                 ; Remove zero input bytes
                 jml     ToStrip
+
+; Insert the core GTE functions
+
+                put     CoreImpl.s
+                put     Memory.s
+                put     Timer.s
+;                put     Graphics.s
+;                put     blitter/Template.s
+                put     blitter/Tables.s
diff --git a/src/_FileInformation.txt b/src/_FileInformation.txt
new file mode 100644
index 0000000..54452a1
--- /dev/null
+++ b/src/_FileInformation.txt
@@ -0,0 +1,2 @@
+Tool=Type(00),AuxType(0000),VersionCreate(70),MinVersion(BE),Access(E3),FolderInfo1(000000000000000000000000000000000000),FolderInfo2(000000000000000000000000000000000000)
+GTETool=Type(BA),AuxType(0000),VersionCreate(70),MinVersion(BE),Access(E3),FolderInfo1(000000000000000000000000000000000000),FolderInfo2(000000000000000000000000000000000000)
diff --git a/src/blitter/Tables.s b/src/blitter/Tables.s
index 44bf70c..bbe0a3d 100644
--- a/src/blitter/Tables.s
+++ b/src/blitter/Tables.s
@@ -19,25 +19,26 @@
 ;
 ; Remember, because the data is pushed on to the stack, the last instruction, which is
 ; in the highest memory location, pushed data that apepars on the left edge of the screen.
-PER_TILE_SIZE     equ   3
-]step             equ   0
 
-                  dw    CODE_TOP    ; There is a spot where we load Col2CodeOffet-2,x
-Col2CodeOffset    lup   82
-                  dw    CODE_TOP+{{81-]step}*PER_TILE_SIZE}
-]step             equ   ]step+1
-                  --^
-                  dw    CODE_TOP+{81*PER_TILE_SIZE}
+;PER_TILE_SIZE     equ   3
+;]step             equ   0
+
+;                  dw    CODE_TOP    ; There is a spot where we load Col2CodeOffet-2,x
+;Col2CodeOffset    lup   82
+;                  dw    CODE_TOP+{{81-]step}*PER_TILE_SIZE}
+;]step             equ   ]step+1
+;                  --^
+;                  dw    CODE_TOP+{81*PER_TILE_SIZE}
 
 ; A parallel table to Col2CodeOffset that holds the offset to the exception handler address for each column
-SNIPPET_SIZE      equ   32
-]step             equ   0
-                  dw    SNIPPET_BASE
-JTableOffset      lup   82
-                  dw    SNIPPET_BASE+{{81-]step}*SNIPPET_SIZE}
-]step             equ   ]step+1
-                  --^
-                  dw    SNIPPET_BASE+{81*SNIPPET_SIZE}
+;SNIPPET_SIZE      equ   32
+;]step             equ   0
+;                  dw    SNIPPET_BASE
+;JTableOffset      lup   82
+;                  dw    SNIPPET_BASE+{{81-]step}*SNIPPET_SIZE}
+;]step             equ   ]step+1
+;                  --^
+;                  dw    SNIPPET_BASE+{81*SNIPPET_SIZE}
 
 ; Table of BRA instructions that are used to exit the code field.  Separate tables for
 ; even and odd aligned cases.
diff --git a/src/blitter/Template.s b/src/blitter/Template.s
index 82446a8..651d62e 100644
--- a/src/blitter/Template.s
+++ b/src/blitter/Template.s
@@ -155,7 +155,6 @@ SetScreenRect      sty   ScreenHeight               ; Save the screen height and
                    cpx   #TILE_STORE_SIZE-2
                    bcc   :tsloop
 
-; Return
                    rts
 
 ; Generalized routine that calculates the on-screen address of the tiles and takes the 
diff --git a/src/blitter/Tiles.s b/src/blitter/Tiles.s
index 45c45ac..0a9f66e 100644
--- a/src/blitter/Tiles.s
+++ b/src/blitter/Tiles.s
@@ -74,7 +74,7 @@ _GetBaseTileAddr
                  asl                                               ; x64
                  asl                                               ; x128
                  rts
-
+                 
 ; On entry
 ;
 ; B is set to the correct BG1 data bank
@@ -102,9 +102,14 @@ _RenderTileBG1
 ; Given an address to a Tile Store record, dispatch to the appropriate tile renderer.  The Tile
 ; Store record contains all of the low-level information that's needed to call the renderer.
 ;
+; There are two execution paths that are handled here.  First, if there is no sprite, then
+; the tile data is read directly and written into the code field in a single pass. If there
+; are sprites that overlap the tile, then the sprite data is combined with the tile data
+; and written to a temporary direct page buffer.  If 
+;
 ; This routine sets the direct page register to the second page since we use that space to 
 ; build and cache tile and sprite data, when necessary
-; Y = address of tile
+
 _RenderTile2
                  lda   TileStore+TS_SPRITE_FLAG,x     ; This is a bitfield of all the sprites that intersect this tile, only care if non-zero or not
                  bne   do_dirty_sprite
@@ -159,10 +164,19 @@ do_dirty_sprite
                  pei   TileStoreBankAndTileDataBank   ; Special value that has the TileStore bank in LSB and TileData bank in MSB
                  plb
 
-; Cache a couple of values into the direct page, but preserve the Accumulator
+; Cache a couple of values into the direct page that are used across all copy routines
 
-                 ldy   TileStore+TS_TILE_ADDR,x       ; load the address of this tile's data (pre-calculated)
-                 sty   tileAddr
+                 lda   TileStore+TS_TILE_ADDR,y       ; load the address of this tile's data (pre-calculated)
+                 sta   tileAddr
+
+                 ldx   TileStore+TS_VBUFF_ADDR_COUNT,y
+                 jmp   (dirty_sprite_dispatch,x)
+dirty_sprite_dispatch
+                 da    CopyNoSprites
+                 da    CopyOneSprite
+                 da    CopyTwoSprites
+                 da    CopyThreeSprites
+                 da    CopyFourSprites                     ; MAX, don't bother with more than 4 sprites per tile
 
 ; This is very similar to the code in the dirty tile renderer, but we can't reuse 
 ; because that code draws directly to the graphics screen, and this code draws
@@ -243,7 +257,15 @@ do_dirty_sprite
 
 ; We set up direct page pointers to the mask bank and use the bank register for the
 ; data.
-CopyFourSpritesAbove
+CopyFourSprites
+                 lda   TileStore+TS_VBUFF_ADDR_0,y
+                 sta   spriteIdx
+                 lda   TileStore+TS_VBUFF_ADDR_1,y
+                 sta   spriteIdx+4
+                 lda   TileStore+TS_VBUFF_ADDR_2,y
+                 sta   spriteIdx+8
+                 lda   TileStore+TS_VBUFF_ADDR_3,y
+                 sta   spriteIdx+12
 
 ; Copy three sprites into a temporary direct page buffer
 LDA_IL           equ   $A7    ; lda [dp]
@@ -252,6 +274,13 @@ AND_IL           equ   $27    ; and [dp]
 AND_ILY          equ   $37    ; and [dp],y
 
 CopyThreeSprites
+                 lda   TileStore+TS_VBUFF_ADDR_0,y
+                 sta   spriteIdx
+                 lda   TileStore+TS_VBUFF_ADDR_1,y
+                 sta   spriteIdx+4
+                 lda   TileStore+TS_VBUFF_ADDR_2,y
+                 sta   spriteIdx+8
+
 ]line            equ   0
                  lup   8
                  ldy   #]line*SPRITE_PLANE_SPAN
@@ -285,6 +314,11 @@ CopyThreeSprites
 
 ; Copy two sprites into a temporary direct page buffer
 CopyTwoSprites
+                 lda   TileStore+TS_VBUFF_ADDR_0,y
+                 sta   spriteIdx
+                 lda   TileStore+TS_VBUFF_ADDR_1,y
+                 sta   spriteIdx+4
+
 ]line            equ   0
                  lup   8
                  ldy   #]line*SPRITE_PLANE_SPAN
@@ -311,9 +345,56 @@ CopyTwoSprites
 ;                 jmp   FinishTile
 
 ; Copy a single piece of sprite data into a temporary direct page . X = spriteIdx
+;
+; X register is the offset of the underlying tile data
+; Y register is the line offset into the sprite data and mask buffers
+; There is a pointer for each sprite on the direct page that can be used
+; to access both the data and mask components of a sprite
+; The Data Bank reigster points to the sprite data
+;
+;    ldal   tiledata,x
+;    and    [spriteIdx],y
+;    ora    (spriteIdx),y
+;    sta    tmp_sprite_data
+;
+; For multiple sprites, we can chain together the and/ora instructions to stack the sprites
+;
+;    ldal   tiledata,x
+;    and    [spriteIdx],y
+;    ora    (spriteIdx),y
+;    and    [spriteIdx+4],y
+;    ora    (spriteIdx+4),y
+;    and    [spriteIdx+8],y
+;    ora    (spriteIdx+8),y
+;    sta    tmp_sprite_data
+;
+; When the sprites need to be drawn on top of the background, then change the order of operations
+;
+;    lda    (spriteIdx),y
+;    and    [spriteIdx+4],y
+;    ora    (spriteIdx+4),y
+;    and    [spriteIdx+8],y
+;    ora    (spriteIdx+8),y
+;    sta    tmp_sprite_data
+;    andl   tiledata+32,x
+;    oral   tiledata,x
+;
 CopyOneSprite
+                 clc
+                 lda   TileStore+TS_VBUFF_ADDR_0,y
+                 sta   spriteIdx
+                 adc   #2
+                 sta   spriteIdx+4
+
 ]line            equ   0
                  lup   8
+                 ldal  tiledata,x
+                 and   [spriteIdx]
+                 ora   (spriteIdx)
+                 sta   tmp_sprite_data+{]line*4}
+
+
+
                  ldal  spritedata+{]line*SPRITE_PLANE_SPAN},x
                  sta   tmp_sprite_data+{]line*4}
                  ldal  spritedata+{]line*SPRITE_PLANE_SPAN}+2,x
diff --git a/src/static/SprData.s b/src/static/SprData.s
new file mode 100644
index 0000000..0c3b85e
--- /dev/null
+++ b/src/static/SprData.s
@@ -0,0 +1,3 @@
+; sprite stamp pixel data
+spritedata ENT
+           ds   65536
\ No newline at end of file
diff --git a/src/static/SprMask.s b/src/static/SprMask.s
new file mode 100644
index 0000000..13de529
--- /dev/null
+++ b/src/static/SprMask.s
@@ -0,0 +1,3 @@
+; sprite stamp masks
+spritemask ENT
+           ds   65536
\ No newline at end of file
diff --git a/src/static/TileData.s b/src/static/TileData.s
new file mode 100644
index 0000000..233da6c
--- /dev/null
+++ b/src/static/TileData.s
@@ -0,0 +1,3 @@
+; Bank of memory that holds the 8x8 tile data
+tiledata  ENT
+          ds   65536
\ No newline at end of file
diff --git a/src/static/TileStore.s b/src/static/TileStore.s
new file mode 100644
index 0000000..101700f
--- /dev/null
+++ b/src/static/TileStore.s
@@ -0,0 +1,3 @@
+; Bank of memory that holds the core sprite and tile store data structures
+TileStore  ENT
+           ds   65536
\ No newline at end of file