Subversion Repositories theia_gpu

/**********************************************************************************

Theaia, Ray Cast Programable graphic Processing Unit.

Copyright (C) 2009  Diego Valverde (diego.valverde.g@gmail.com)

This program is free software; you can redistribute it and/or

modify it under the terms of the GNU General Public License

as published by the Free Software Foundation; either version 2

of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

***********************************************************************************/

/**********************************************************************************

Module Description:

WIP

**********************************************************************************/

`timescale 1ns / 1ps

`include "aDefinitions.v"

`define GFSM_AFTER_RESET                       0

`define GFSM_INITIAL_STATE                     1

`define GFSM_TRIGGER_AABBIU                    2

`define GFSM_WAIT_FOR_AABBIU                   3

`define GFSM_ACK_AABBIU                       10

`define GFSM_AABBIU_HIT                        4

`define GFSM_AABBIU_NO_HIT                     5

`define GFSM_TRIGGER_TRIANGLE_FETCH            6

`define GFSM_WAIT_FOR_TRIANGLE_FETCH           7

`define GFSM_TRIGGER_BIU_REQUSET               8

`define GFSM_WAIT_FOR_BIU                      9

`define GFSM_GET_FIRST_CHILD                  11

`define GFSM_CHECK_TRIANGLE_COUNT             12

`define GFSM_CHECK_NEXT_BROTHER               13

`define GFSM_GET_BROTHER                      14

`define GFSM_TRIGGER_NODE_FETCH               15

`define GFSM_FETCH_NEXT_BROTHER               16

`define GFSM_CHECK_PARENTS_BROTHER            18

`define GFSM_GET_PARENTS_BROTHER              19

`define GFSM_WAIT_FOR_NODE_FETCH              20

`define GFSM_POST_BLOCK_READ_DELAY            21

`define GFSM_TRIGGER_ROOT_NODE_FETCH          23

`define GFSM_WAIT_FOR_ROOT_NODE_FETCH         24

`define GFSM_FETCH_DATA                       25

`define GFSM_WAITF_FOR_BIU_AVAILABLE          26

`define GFSM_SWAP_TRIANGLE_POINTER            27

`define GFSM_DONE                             28

`define GFSM_SET_TRIANGLE_LIST_INITIAL_OFFSET 29

`define GFSM_REQUEST_TCC                      30

`define GFSM_WAIT_FOR_TCC                     31

`define GFSM_WAIT_STATE_PRE_TCC               32

`define GFSM_INITIAL_STATE_TEXTURE            33

`define GFSM_SET_WBM_INITIAL_ADDRESS          34

`define GFSM_REQUEST_TEXTURE                  35

`define GFSM_WAIT_FOR_TEXTURE                 36

`define GFSM_REQUEST_NEXT_TEXTURE             37

`define GFSM_WAIT_FOR_NEXT_TEXTURE            38

`define GFSM_INC_TEXTURE_ADDRESS              39

`define GFSM_SET_NEXT_TEXTURE_ADDR            42

`define GFSM_WAIT_FOR_IO_HIT                  43

`define GFSM_WAIT_FOR_IO_NO_HIT               44

module GeometryFetchFSM

(

        input wire                    Clock,

        input wire                    Reset,

        //Input control signals

        input wire                    iEnable,

        input   wire                    iAABBIUHit,

        input wire                    iBIUHit,

        input   wire                    iUCodeDone,

        input wire                    iTexturingEnable,

        input   wire                    iTriangleReadDone,

        //input wire                 iTextureReadDone,

        input   wire                    iNodeReadDone,

        //Current Node info

        input   wire                    iNode_IsLeaf,

        input wire[`WIDTH-1:0]        iNode_Brother_Address,

        input wire[`WIDTH-1:0]        iNode_TriangleCount,

        input wire[`WIDTH-1:0]        iNode_Parents_Brother_Address,

        //input wire[`WIDTH-1:0]                Node_OffsetData_Address,

        input wire[`WIDTH-1:0]        iNode_FirstChild_Address,

        //input wire                                            iBIUAvailable,

        //input wire                                            Node_MaxBlocks,

        //Control output signals

        output reg                                                                              oEnable_WBM,        //Activate the WBM in I/O

        output wire[`DATA_ADDRESS_WIDTH-1:0]     oAddressWBM,        //This is the address that we want to read from in I/O

        output reg                                                                              oSetAddressWBM,     //This uis to tell I/O to use the adress we just set

        output reg                             oSetIOWriteBackAddr,

        output wire[`DATA_ADDRESS_WIDTH-1:0]     oRAMTextureStoreLocation,   //This is where we want to store the data comming from I/O

        input   wire                                                   iDataAvailable,

        input wire                             iIOBusy,

        output reg      [`WIDTH-1:0]      oNodeAddress,

        input wire                                                      iTrigger_TFF,

        output reg                    oRequest_AABBIU,

        output reg                    oRequest_BIU,

        output reg                    oRequest_TCC,

        output reg                    oTrigger_TFU,

        output reg                    oTrigger_TNF,

        output reg [1:0]              oWBM_Addr_Selector, //0 = TNF, 1 = TFU, 2 = TCC 

        output reg                    oSync,

        output reg                    oSetTFUAddressOffset,

        `ifdef DEBUG

        input wire[`MAX_CORES-1:0]            iDebug_CoreID,

        `endif

        output reg                    oDone

);

reg [6:0] CurrentState;

reg [6:0] NextState;

//reg //IncTextureWriteAddress;

reg IncTextureCoordRegrAddr,IncTextureCount;

wire [2:0]  wTextureCount;

reg IncTriangleCount,ClearTriangleCount;

wire [`WIDTH-1:0] wTriangleCount;

//----------------------------------------

UpCounter_32 UP32_Tricount

(

.Clock( Clock ),

.Reset( ClearTriangleCount ),

.Initial( 0 ),

.Enable( IncTriangleCount ),

.Q( wTriangleCount )

);

//-----------------------------

UpCounter_16E TFF_VC1a

(

.Clock( Clock ),

.Reset( iTrigger_TFF | Reset ),

.Initial( `OREG_TEX_COORD1 ),

.Enable( IncTextureCoordRegrAddr ),

.Q( oAddressWBM )

);

//assign oAddressWBM = `OREG_TEX_COORD1;

//-----------------------------

UPCOUNTER_POSEDGE # (3) TFF_VC1

(

.Clock( Clock ),

.Reset( iTrigger_TFF ),

.Initial( 3'b0 ),

.Enable( IncTextureCount ),

.Q(  wTextureCount )

);

//-----------------------------

assign oRAMTextureStoreLocation = `CREG_TEX_COLOR1;

/*

UPCOUNTER_POSEDGE # (16) TNF_TFU_2

(

.Clock( Clock ),

.Reset( iTrigger_TFF ),

.Initial( `CREG_TEX_COLOR1 ),

.Enable(  //IncTextureWriteAddress ),

.Q( oRAMTextureStoreLocation )

);

*/

//----------------------------------------

`define GFSM_SELECT_TFU 2'b00  //Triangle Fetch

`define GFSM_SELECT_TFF 2'b01  //Texture Fetch     

`define GFSM_SELECT_TNF 2'b10  //Tree node fetch

`define GFSM_SELECT_NULL 2'b11

        //------------------------------------------------

  always @(posedge Clock or posedge Reset)

  begin

    if (Reset)

                CurrentState <= `GFSM_AFTER_RESET;

    else

                CurrentState <= NextState;

  end

  //------------------------------------------------

        always @( * )

   begin

        case (CurrentState)

                  //------------------------------------------

                  `GFSM_AFTER_RESET:

                  begin

                                oNodeAddress                    <= 0;

                                oRequest_AABBIU         <= 0;

                                oRequest_BIU                    <= 0;

                                oTrigger_TFU                    <= 0;

                                oTrigger_TNF                    <= 0;

                                ClearTriangleCount      <= 0;

                                IncTriangleCount                <= 0;

                                oWBM_Addr_Selector      <= `GFSM_SELECT_NULL;

                                oSync                                           <= 0;

                                oDone                                           <= 0;

                                oSetTFUAddressOffset <= 0;

                                oRequest_TCC         <= 0;

                                IncTextureCoordRegrAddr       <= 0;

                                oSetIOWriteBackAddr <= 0;

                                //oRAMTextureStoreLocation <= `DATA_ADDRESS_WIDTH'd0;

                                NextState       <= `GFSM_INITIAL_STATE;

                  end

                  //------------------------------------------

                  /*

                  Here two things ca happen:

                  1) We are onGeometry Fetch Mode (iTrigger_TFF == 0)

                  then get the first node in the Octant Tree, or,

                  2)We are on Texture Fetch Mode (iTrigger_TFF == 1)

                  then do texture fetch stuff...

                  */

                  `GFSM_INITIAL_STATE:

                  begin

                                oNodeAddress                    <= 0;

                                oRequest_AABBIU         <= 0;

                                oRequest_BIU                    <= 0;

                                oTrigger_TFU                    <= 0;

                                oTrigger_TNF                    <= 0;

                                ClearTriangleCount      <= 1;   //*

                                IncTriangleCount                <= 0;

                                oWBM_Addr_Selector      <= `GFSM_SELECT_NULL;

                                oSync                                           <= 0;

                                oDone                                           <= 0;

                                oSetTFUAddressOffset <= 0;

                                oRequest_TCC         <= 0;

                                IncTextureCoordRegrAddr       <= 0;

                                oSetIOWriteBackAddr <= 0;

                                //oRAMTextureStoreLocation <= `DATA_ADDRESS_WIDTH'd0;

                                if ( iEnable && !iTrigger_TFF )

                                        NextState <= `GFSM_TRIGGER_ROOT_NODE_FETCH;

                                else if (iEnable && iTrigger_TFF)

                                        NextState <= `GFSM_SET_WBM_INITIAL_ADDRESS;

                                else

                                        NextState <= `GFSM_INITIAL_STATE;

                  end

                  //------------------------------------------

                  `GFSM_SET_WBM_INITIAL_ADDRESS:

                  begin

                                oNodeAddress                    <= 0;

                                oRequest_AABBIU         <= 0;

                                oRequest_BIU                    <= 0;

                                oTrigger_TFU                    <= 0;

                                oTrigger_TNF                    <= 0;

                                ClearTriangleCount      <= 0;

                                IncTriangleCount                <= 0;

                                oWBM_Addr_Selector      <= `GFSM_SELECT_TFF;

                                oSync                                           <= 0;

                                oDone                                           <= 0;

                                oSetTFUAddressOffset <= 0;

                                oRequest_TCC         <= 0;

                                oEnable_WBM                      <= 0;

                                oSetAddressWBM                <= 1; //*

                                oSetIOWriteBackAddr     <= 1; //Make sure we set write back address

                                IncTextureCount       <= 0;

                                IncTextureCoordRegrAddr <= 0;

                                NextState <= `GFSM_REQUEST_TEXTURE;

                end

                //------------------------------------

                `GFSM_REQUEST_TEXTURE:

                begin

                        oNodeAddress                    <= 0;

                        oRequest_AABBIU         <= 0;

                        oRequest_BIU                    <= 0;

                        oTrigger_TFU                    <= 0;

                        oTrigger_TNF                    <= 0;

                        ClearTriangleCount      <= 0;

                        IncTriangleCount                <= 0;

                        oWBM_Addr_Selector      <= `GFSM_SELECT_TFF;

                        oSync                                           <= 0;

                        oDone                                           <= 0;

                        oSetTFUAddressOffset <= 0;

                        oRequest_TCC         <= 0;

                        //$display("GFSM_REQUEST_TEXTURE: Texture Addr in Reg: %d",oAddressWBM);

                        oEnable_WBM              <= 1; //*

                        oSetAddressWBM                 <= 0;

                        IncTextureCount        <= 0; //*

                        IncTextureCoordRegrAddr  <= 0;

                        oSetIOWriteBackAddr <= 0;

                        NextState <= `GFSM_WAIT_FOR_TEXTURE;

                end

                //------------------------------------

                `GFSM_WAIT_FOR_TEXTURE:

                begin

         oNodeAddress                   <= 0;

                        oRequest_AABBIU         <= 0;

                        oRequest_BIU                    <= 0;

                        oTrigger_TFU                    <= 0;

                        oTrigger_TNF                    <= 0;

                        ClearTriangleCount      <= 0;

                        IncTriangleCount                <= 0;

                        oWBM_Addr_Selector      <= `GFSM_SELECT_TFF;

                        oSync                                           <= 0;

                        oDone                                           <= 0;

                        oSetTFUAddressOffset <= 0;

                        oRequest_TCC         <= 0;

                        oEnable_WBM                <= 1;

                        oSetAddressWBM                   <= 0;

                        //IncTextureWriteAddress           <= 0;

                        IncTextureCount            <= 0;

                        IncTextureCoordRegrAddr      <= 0;

                        oSetIOWriteBackAddr <= 0;

                        //oRAMTextureStoreLocation <= `CREG_TEX_COLOR1;

                if ( iDataAvailable )

                        NextState <= `GFSM_INC_TEXTURE_ADDRESS;

                else

                        NextState <= `GFSM_WAIT_FOR_TEXTURE;

                end

                //------------------------------------

                `GFSM_INC_TEXTURE_ADDRESS:

                begin

                //$display("***** GFSM_REQUEST_NEXT_TEXTURE: Texture Addr in Reg: %d",oAddressWBM);

                   oNodeAddress                 <= 0;

                        oRequest_AABBIU         <= 0;

                        oRequest_BIU                    <= 0;

                        oTrigger_TFU                    <= 0;

                        oTrigger_TNF                    <= 0;

                        ClearTriangleCount      <= 0;

                        IncTriangleCount                <= 0;

                        oWBM_Addr_Selector      <= `GFSM_SELECT_TFF;

                        oSync                                           <= 0;

                        oDone                                           <= 0;

                        oSetTFUAddressOffset <= 0;

                        oRequest_TCC         <= 0;

                        oEnable_WBM            <= 0;

                        oSetAddressWBM                <= 0;

                        IncTextureCount       <= 1;

                        //IncTextureWriteAddress        <= 0;//1;

         IncTextureCoordRegrAddr <= 1; //*              

                        oSetIOWriteBackAddr <= 0;

                        //oRAMTextureStoreLocation <= `CREG_TEX_COLOR4;                 

                        NextState <= `GFSM_SET_NEXT_TEXTURE_ADDR;

                end

                //------------------------------------

                `GFSM_SET_NEXT_TEXTURE_ADDR:

                begin

                //$display("***** GFSM_REQUEST_NEXT_TEXTURE: Texture Addr in Reg: %d",oAddressWBM);

                   oNodeAddress                 <= 0;

                        oRequest_AABBIU         <= 0;

                        oRequest_BIU                    <= 0;

                        oTrigger_TFU                    <= 0;

                        oTrigger_TNF                    <= 0;

                        ClearTriangleCount      <= 0;

                        IncTriangleCount                <= 0;

                        oWBM_Addr_Selector      <= `GFSM_SELECT_TFF;

                        oSync                                           <= 0;

                        oDone                                           <= 0;

                        oSetTFUAddressOffset <= 0;

                        oRequest_TCC         <= 0;

                        oEnable_WBM            <= 0; //*

                        oSetAddressWBM                <= 1;

                        IncTextureCount       <= 0; //*

         IncTextureCoordRegrAddr <= 0;

                        oSetIOWriteBackAddr <= 0;

                        //oRAMTextureStoreLocation <= `CREG_TEX_COLOR4;                 

                        NextState <= `GFSM_REQUEST_NEXT_TEXTURE;

                end

                //------------------------------------

                /*

                We request 6 textures (ie. six colors from

                the texture coordinates, it should be actually 4

                instead of 6, but the hardwardware works better

                with numbers that are power of 3. But read 3 at

                a time, so when TextureCount Reaches 2 then we

                are done

                */

                `GFSM_REQUEST_NEXT_TEXTURE:

                begin

                //$display("***** GFSM_REQUEST_NEXT_TEXTURE: Texture Addr in Reg: %d",oAddressWBM);

                   oNodeAddress                 <= 0;

                        oRequest_AABBIU         <= 0;

                        oRequest_BIU                    <= 0;

                        oTrigger_TFU                    <= 0;

                        oTrigger_TNF                    <= 0;

                        ClearTriangleCount      <= 0;

                        IncTriangleCount                <= 0;

                        oWBM_Addr_Selector      <= `GFSM_SELECT_TFF;

                        oSync                                           <= 0;

                        oDone                                           <= 0;

                        oSetTFUAddressOffset <= 0;

                        oRequest_TCC         <= 0;

                        oEnable_WBM            <= 1; //*

                        oSetAddressWBM                <= 0;

                        IncTextureCount       <= 1; //*

         IncTextureCoordRegrAddr <= 0;

                        oSetIOWriteBackAddr <= 0;

                        //oRAMTextureStoreLocation <= `CREG_TEX_COLOR4;                 

                        NextState <= `GFSM_WAIT_FOR_NEXT_TEXTURE;

                end

                //----------------------------------------

                `GFSM_WAIT_FOR_NEXT_TEXTURE:

                begin

                        oNodeAddress                    <= 0;

                        oRequest_AABBIU         <= 0;

                        oRequest_BIU                    <= 0;

                        oTrigger_TFU                    <= 0;

                        oTrigger_TNF                    <= 0;

                        ClearTriangleCount      <= 0;

                        IncTriangleCount                <= 0;

                        oWBM_Addr_Selector      <= `GFSM_SELECT_TFF;

                        oSync                                           <= 0;

                        oDone                                           <= 0;

                        oSetTFUAddressOffset <= 0;

                        oRequest_TCC         <= 0;

                        oEnable_WBM                 <= 1;

                        oSetAddressWBM                     <= 0;

                        IncTextureCount            <= 0; //*

                        IncTextureCoordRegrAddr      <= 0;

                        oSetIOWriteBackAddr <= 0;

                        //oRAMTextureStoreLocation <= `CREG_TEX_COLOR4;

                if ( iDataAvailable )

                        NextState <= `GFSM_DONE;

                else

                        NextState <= `GFSM_WAIT_FOR_NEXT_TEXTURE;

                end

                        /****************************************/

                        /*

                        Texture Fetch Logic Ends Here.

                        Geometry Fetch Logic Starts Here (Duh!)

                        */

                        //------------------------------------

                   /*

                        Lets request the Root Node read in here.

                        The tree node function will fetch info such as

                        the type of node, the address of the first

                        data block as well as the boundaries of the

                        AABB.

                  */

                  `GFSM_TRIGGER_ROOT_NODE_FETCH:

                  begin

                  `ifdef DEBUG_GFSM

                   if (iDebug_CoreID == `DEBUG_CORE)

                                $display("CORE %d GFSM_TRIGGER_ROOT_NODE_FETCH",iDebug_CoreID);

                        `endif

                                oNodeAddress                    <= 0;     //Address of root node is always zero

                                oRequest_AABBIU         <= 0;

                                oRequest_BIU                    <= 0;

                                oTrigger_TFU                    <= 0;

                                oTrigger_TNF                    <= 1;   //*

                                ClearTriangleCount      <= 0;

                                IncTriangleCount                <= 0;

                                oWBM_Addr_Selector      <= `GFSM_SELECT_TNF;

                                oSync                                           <= 0;

                                oDone                                           <= 0;

                                oSetTFUAddressOffset <= 0;

                                oRequest_TCC         <= 0;

                                oEnable_WBM                   <= 0;

                                oSetAddressWBM                <= 0;

                                //IncTextureWriteAddress        <= 0;

                                IncTextureCount       <= 0;

                                IncTextureCoordRegrAddr      <= 0;

                                oSetIOWriteBackAddr <= 0;

                                //oRAMTextureStoreLocation <= `DATA_ADDRESS_WIDTH'd0;

                                NextState <= `GFSM_WAIT_FOR_ROOT_NODE_FETCH;

                  end

                  //------------------------------------------

                  /*

                        OK once we have the data the first ting is

                        to test if the ray hits the AABB.

                  */

                  `GFSM_WAIT_FOR_ROOT_NODE_FETCH:

                  begin

                                oNodeAddress                    <= 0;

                                oRequest_AABBIU         <= 0;

                                oRequest_BIU                    <= 0;

                                oTrigger_TFU                    <= 0;

                                oTrigger_TNF                    <= 0;//* 

                                ClearTriangleCount      <= 0;

                                IncTriangleCount                <= 0;

                                oWBM_Addr_Selector      <= `GFSM_SELECT_TNF;

                                oSync                                           <= 0;

                                oDone                                           <= 0;

                                oSetTFUAddressOffset <= 0;

                                oRequest_TCC         <= 0;

                                oEnable_WBM                   <= 0;

                                oSetAddressWBM                <= 0;

                                //IncTextureWriteAddress        <= 0;

                                IncTextureCount       <= 0;

                                IncTextureCoordRegrAddr      <= 0;

                                oSetIOWriteBackAddr <= 0;

                                //oRAMTextureStoreLocation <= `DATA_ADDRESS_WIDTH'd0;

                                if (iNodeReadDone)

                                        NextState <= `GFSM_TRIGGER_AABBIU;

                                else

                                        NextState <= `GFSM_WAIT_FOR_ROOT_NODE_FETCH;

                  end

                  //------------------------------------------

                  /*

                  So, while we request AABBIU, we should be requesting

                  the info for the Next triangle as well...

                  */

                  `GFSM_TRIGGER_AABBIU:

                  begin

                                oNodeAddress                    <= 0;

                                oRequest_AABBIU         <= 1;   //*

                                oRequest_BIU                    <= 0;

                                oTrigger_TFU                    <= 0;   //WIP!!!!!!!!

                                oTrigger_TNF                    <= 0;

                                ClearTriangleCount      <= 0;

                                IncTriangleCount                <= 0;

                                oWBM_Addr_Selector      <= `GFSM_SELECT_NULL;

                                oSync                                           <= 1; //*

                                oDone                                           <= 0;

                                oSetTFUAddressOffset <= 0;

                                oRequest_TCC         <= 0;

                                oEnable_WBM                   <= 0;

                                oSetAddressWBM                <= 0;

                                //IncTextureWriteAddress        <= 0;

                                IncTextureCount       <= 0;

                                IncTextureCoordRegrAddr      <= 0;

                                oSetIOWriteBackAddr <= 0;

                                //oRAMTextureStoreLocation <= `DATA_ADDRESS_WIDTH'd0;                           

                                NextState <= `GFSM_WAIT_FOR_AABBIU;

                  end

                  //------------------------------------------

                  `GFSM_WAIT_FOR_AABBIU:

                  begin

                                oNodeAddress                    <= 0;

                                oRequest_AABBIU         <= 1;

                                oRequest_BIU                    <= 0;

                                oTrigger_TFU                    <= 0;

                                oTrigger_TNF                    <= 0;

                                ClearTriangleCount      <= 0;

                                IncTriangleCount                <= 0;

                                oWBM_Addr_Selector      <= `GFSM_SELECT_NULL;

                                oSync                                           <= 0;

                                oDone                                           <= 0;

                                oSetTFUAddressOffset <= 0;

                                oRequest_TCC         <= 0;

                                oEnable_WBM                   <= 0;

                                oSetAddressWBM                <= 0;

                                //IncTextureWriteAddress        <= 0;

                                IncTextureCount       <= 0;

                                IncTextureCoordRegrAddr      <= 0;

                                oSetIOWriteBackAddr <= 0;

                                //oRAMTextureStoreLocation <= `DATA_ADDRESS_WIDTH'd0;

                                if ( iUCodeDone )

                                        NextState <= `GFSM_ACK_AABBIU;

                                else

                                        NextState <= `GFSM_WAIT_FOR_AABBIU;

                  end

                  //------------------------------------------

                  `GFSM_ACK_AABBIU:

                  begin

                                oNodeAddress                    <= 0;

                                oRequest_AABBIU         <= 0;    //*

                                oRequest_BIU                    <= 0;

                                oTrigger_TFU                    <= 0;

                                oTrigger_TNF                    <= 0;

                                ClearTriangleCount      <= 0;

                                IncTriangleCount                <= 0;

                                oWBM_Addr_Selector      <= `GFSM_SELECT_NULL;

                                oSync                                           <= 0;

                                oDone                                           <= 0;

                                oSetTFUAddressOffset <= 0;

                                oRequest_TCC         <= 0;

                                oEnable_WBM                   <= 0;

                                oSetAddressWBM                <= 0;

                                //IncTextureWriteAddress        <= 0;

                                IncTextureCount       <= 0;

                                IncTextureCoordRegrAddr      <= 0;

                                oSetIOWriteBackAddr <= 0;

                                //oRAMTextureStoreLocation <= `DATA_ADDRESS_WIDTH'd0;

                                if ( iAABBIUHit )

                                        NextState <= `GFSM_AABBIU_HIT;

                                else

                                        NextState <= `GFSM_AABBIU_NO_HIT;

                  end

                  //------------------------------------------

                  `GFSM_AABBIU_NO_HIT:

                  begin

                                oNodeAddress                    <= 0;

                                oRequest_AABBIU         <= 0;    //*

                                oRequest_BIU                    <= 0;

                                oTrigger_TFU                    <= 0;

                                oTrigger_TNF                    <= 0;

                                ClearTriangleCount      <= 0;

                                IncTriangleCount                <= 0;

                                oWBM_Addr_Selector      <= `GFSM_SELECT_NULL;

                                oSync                                           <= 0;

                                oDone                                           <= 0;

                                oSetTFUAddressOffset <= 0;

                                oRequest_TCC         <= 0;

                                oEnable_WBM                   <= 0;

                                oSetAddressWBM                <= 0;

                                //IncTextureWriteAddress        <= 0;

                                IncTextureCount       <= 0;

                                IncTextureCoordRegrAddr      <= 0;

                                oSetIOWriteBackAddr <= 0;

                                //oRAMTextureStoreLocation <= `DATA_ADDRESS_WIDTH'd0;

                                NextState <= `GFSM_DONE;

                  end

                  //------------------------------------------

                  /*

                   Ok there is a hit, two things can happen:

                   if the Node is not a leaf, then the child nodes

                   need to be tested.

                   Else this node's data linked list needs

                   to be tested for instersections.

                        Since we have a new Node, lets start by

                        reading the first 3 blocks of data. The

                        first block is pointed by

                        'Node_OffsetData_Address'.

                  */

                  `GFSM_AABBIU_HIT:

                  begin

                                oNodeAddress                    <= 0;

                                oRequest_AABBIU         <= 0;

                                oRequest_BIU                    <= 0;

                                oTrigger_TFU                    <= 0;

                                oTrigger_TNF                    <= 0;

                                ClearTriangleCount      <= 0;

                                IncTriangleCount                <= 0;

                                oWBM_Addr_Selector      <= `GFSM_SELECT_NULL;

                                oSync                                           <= 0;

                                oDone                                           <= 0;

                                oSetTFUAddressOffset <= 0;

                                oRequest_TCC         <= 0;

                                oEnable_WBM                   <= 0;

                                oSetAddressWBM                <= 0;

                                //IncTextureWriteAddress        <= 0;

                                IncTextureCount       <= 0;

                                IncTextureCoordRegrAddr      <= 0;

                                oSetIOWriteBackAddr <= 0;

                                //oRAMTextureStoreLocation <= `DATA_ADDRESS_WIDTH'd0;

                                if ( iNode_IsLeaf )

                                        NextState  <= `GFSM_SET_TRIANGLE_LIST_INITIAL_OFFSET;

                                else

                                        NextState  <= `GFSM_GET_FIRST_CHILD;

                  end

                  //------------------------------------------

                  `GFSM_SET_TRIANGLE_LIST_INITIAL_OFFSET:

                  begin

                                oNodeAddress                    <= 0;

                                oRequest_AABBIU         <= 0;

                                oRequest_BIU                    <= 0;

                                oTrigger_TFU                    <= 0;

                                oTrigger_TNF                    <= 0;

                                ClearTriangleCount      <= 0;

                                IncTriangleCount                <= 0;

                                oWBM_Addr_Selector      <= `GFSM_SELECT_NULL;

                                oSync                                           <= 0;

                                oDone                                           <= 0;

                                oSetTFUAddressOffset <= 1; //*

                                oRequest_TCC         <= 0;