Subversion Repositories theia_gpu

`timescale 1ns / 1ps

`include "aDefinitions.v"

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

Theia, Ray Cast Programable graphic Processing Unit.

Copyright (C) 2010  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.

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

/*

This unit is used when the External Address that comes into IO is not a immediate value,

ie. it is a value that we need to read from one of our internal memory locations.

Since each internal memory locations contains 3 * 32bits slots, ie X,Y and Z parts of the

memory location, then we make three requests for external data, one for every X Y and Z

part of our internal registry.So, summarising, each internal memory location, stores 3

external memory addresses to request to WBM. Once the 3 data has been read from outside world,

they will get stored back into 3 consecutive inernal memory addreses starting from

iDataInitialStorageAddress

*/

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

module MEM2WBMUnitB

(

input wire                          Clock,

input wire                          Reset,

input wire                                                                      iEnable,

//output reg                          oSetAddress,

input wire[`DATA_ADDRESS_WIDTH-1:0]  iMEMDataPointer,

input wire[`DATA_ADDRESS_WIDTH-1:0]  iMEMDataPointer2,

output wire [`WIDTH-1:0]            oReadDataElement,

output wire [`WIDTH-1:0]            oReadDataElement2,

output wire[`DATA_ADDRESS_WIDTH-1:0] oDataReadAddress,    //This tells MEM unit from wich address we want to read

output wire[`DATA_ADDRESS_WIDTH-1:0] oDataReadAddress2,    //This tells MEM unit from wich address we want to read

input wire [`DATA_ROW_WIDTH-1:0]         iReadDataBus,             //This comes from the MEM unit

input wire [`DATA_ROW_WIDTH-1:0]         iReadDataBus2,            //This comes from the MEM unit

output wire                                                                     oDataWriteEnable,

output wire                                                                     oDataWriteEnable2,

output wire                          oDataAvailable,

input wire                          iRequestNextElement,

input wire[`DATA_ADDRESS_WIDTH-1:0]  iDataInitialStorageAddress, //Initial address to store data ////########

output wire[`DATA_ADDRESS_WIDTH-1:0] oDataWriteAddress,  //Were to store the values comming from WBM ////########

output wire                          oDone

);

assign oDataWriteEnable2 = 0;

assign oDataWriteEnable = 0; //We only read.

wire [3:0] wXYZSelector;

wire[`WIDTH-1:0] wValueFromBus,wLatchedValue;

assign oDataReadAddress = iMEMDataPointer;

assign oDataReadAddress2 = iMEMDataPointer2;

assign oDone = wXYZSelector[3];

wire wLacthNow;

assign oDataAvailable = iEnable & ~iRequestNextElement & wLacthNow & ~oDone;

FFD_POSEDGE_SYNCRONOUS_RESET # (1) FFD32_EnableDelay

(

        .Clock(         Clock ),

        .Reset(         Reset ),

        .Enable( 1'b1 ),

        .D( iEnable ),

        .Q( wLacthNow )

);

assign oDataWriteAddress = iDataInitialStorageAddress;

SHIFTLEFT_POSEDGE #(4) SHL

(

  .Clock(iRequestNextElement | ~iEnable),

  .Enable(1'b1),

  .Reset(~iEnable | Reset ),

  .Initial(4'b1),

  .O(wXYZSelector)

);

MUXFULLPARALELL_3SEL_WALKINGONE MUXA

 (

 .Sel( wXYZSelector ),

 .I2( iReadDataBus[63:32]),

 .I1( iReadDataBus[95:64]),

 .I3( iReadDataBus[31:0] ),

 .O1( oReadDataElement )

 );

MUXFULLPARALELL_3SEL_WALKINGONE MUXA2

 (

 .Sel( wXYZSelector ),

 .I2( iReadDataBus2[63:32]),

 .I1( iReadDataBus2[95:64]),

 .I3( iReadDataBus2[31:0] ),

 .O1( oReadDataElement2 )

 );

endmodule

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