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[fpgaboy.git] / LCDC.v

diff --git a/LCDC.v b/LCDC.v
index 8f237eb1aae11a5e11271ec28b00a52dfc3143ab..9cebfd7d161712d690dd561749d1a48b0bdfe135 100644 (file)
--- a/LCDC.v
+++ b/LCDC.v
@@ -63,8 +63,8 @@ module LCDC(
        reg [8:0] posx = 9'h000;
        reg [7:0] posy = 8'h00;
        
-       wire vraminuse = (posx < 163);
-       wire oaminuse = (posx > 369);
+       wire vraminuse = (posx < 163) && (posy < 144);
+       wire oaminuse = (posx > 369) && (posy < 144);
        
        wire display = (posx > 2) && (posx < 163) && (posy < 144);
        
@@ -74,11 +74,14 @@ module LCDC(
                                 2'b00)
                                : 2'b01;
        
+       wire [7:0] vxpos = rSCX + posx - 3;
+       wire [7:0] vypos = rSCY + posy;
+       
        assign lcdvs = (posy == 153) && (posx == 455);
        assign lcdhs = (posx == 455);
        assign lcdr = display ? {pixdata[1] ? 3'b111 : 3'b000} : 3'b000;
        assign lcdg = display ? {pixdata[0] ? 3'b111 : 3'b000} : 3'b000;
-       assign lcdb = display ? {posy < rSCY ? 2'b11 : 2'b00} : 2'b00;
+       assign lcdb = display ? {(vypos < 8 || vxpos < 8) ? 2'b11 : 2'b00} : 2'b00;
        
        reg mode00irq = 0, mode01irq = 0, mode10irq = 0, lycirq = 0;
        assign lcdcirq = (rSTAT[3] & mode00irq) | (rSTAT[4] & mode01irq) | (rSTAT[5] & mode10irq) | (rSTAT[6] & lycirq);
@@ -123,65 +126,61 @@ module LCDC(
         * Tile data from 8000-8FFF or 8800-97FF
         * Background tile maps 9800-9BFF or 9C00-9FFF
         */
-       reg [7:0] tiledata [6143:0];
+       reg [7:0] tiledatahigh [3071:0];
+       reg [7:0] tiledatalow [3071:0];
        reg [7:0] bgmap1 [1023:0];
        reg [7:0] bgmap2 [1023:0];
        
        // Upper five bits are Y coord, lower five bits are X coord
-       wire [7:0] vxpos = rSCX + posx - 3;
-       wire [7:0] vypos = rSCY + posy;
-       
-       // The new tile number is loaded when vxpos[2:0] is 3'b101
-       // The new tile data low is loaded when vxpos[2:0] is 3'b110
-       // The new tile data high is loaded when vxpos[2:0] is 3'b111
+       // The new tile number is loaded when vxpos[2:0] is 3'b110
+       // The new tile data is loaded when vxpos[2:0] is 3'b111
        // The new tile data is latched and ready when vxpos[2:0] is 3'b000!
        wire [9:0] bgmapaddr = {vypos[7:3], vxpos[7:3]};
        reg [7:0] tileno;
-       wire [10:0] tileaddr = {tileno, vypos[2:1]};
-       reg [7:0] tilelowtmp, tilehigh, tilelow;
+       wire [10:0] tileaddr = {tileno, vypos[2:0]};
+       reg [7:0] tilehigh, tilelow;
        assign pixdata = {tilehigh[vxpos[2:0]], tilelow[vxpos[2:0]]};
        
        wire decode_tiledata = (addr >= 16'h8000) && (addr <= 16'h97FF);
        wire decode_bgmap1 = (addr >= 16'h9800) && (addr <= 16'h9BFF);
+
+       wire [9:0] bgmapaddr_in = vraminuse ? bgmapaddr : addr[9:0];
+       wire [11:0] tileaddr_in = vraminuse ? tileaddr : addr[12:1];
        
        always @(negedge clk)
-               if (vraminuse) begin
-                       if ((posx == 0) || ((posx > 2) && (vxpos[2:0] == 3'b101)))
-                               tileno <= bgmap1[bgmapaddr];
-                       else if ((posx == 1) || ((posx > 2) && (vxpos[2:0] == 3'b110)))
-                               tilelowtmp <= tiledata[{tileaddr, 1'b0}];
-                       else if ((posx == 2) || ((posx > 2) && (vxpos[2:0] == 3'b111))) begin
-                               tilehigh <= tiledata[{tileaddr, 1'b1}];
-                               tilelow <= tilelowtmp;
-                       end
-               end else begin
-                       if (decode_tiledata) begin
-                               tilelowtmp <= tiledata[addr[12:0]];
-                               if (wr)
-                                       tiledata[addr[12:0]] <= data;
-                       end else if (decode_bgmap1) begin
-                               tileno <= bgmap1[addr[12:0]];
-                               if (wr)
-                                       bgmap1[addr[12:0]] <= data;
-                       end
+               if ((vraminuse && ((posx == 1) || ((posx > 2) && (vxpos[2:0] == 3'b110)))) || decode_bgmap1) begin
+                       tileno <= bgmap1[bgmapaddr_in];
+                       if (wr && decode_bgmap1 && ~vraminuse)
+                               bgmap1[bgmapaddr_in] <= data;
+               end
+       
+       always @(negedge clk)
+               if ((vraminuse && ((posx == 2) || ((posx > 2) && (vxpos[2:0] == 3'b111)))) || decode_tiledata) begin
+                       tilehigh <= tiledatahigh[tileaddr_in];
+                       tilelow <= tiledatalow[tileaddr_in];
+                       if (wr && addr[0] && decode_tiledata && ~vraminuse)
+                               tiledatahigh[tileaddr_in] <= data;
+                       if (wr && ~addr[0] && decode_tiledata && ~vraminuse)
+                               tiledatalow[tileaddr_in] <= data;
                end
   
        /***** Bus interface *****/
        assign data = rd ?
-                       (addr == `ADDR_LCDC) ? rLCDC :
-                       (addr == `ADDR_STAT) ? {rSTAT[7:3], (rLYC == posy) ? 1'b1 : 1'b0, mode} :
-                       (addr == `ADDR_SCY) ? rSCY :
-                       (addr == `ADDR_SCX) ? rSCX :
-                       (addr == `ADDR_LY) ? posy :
-                       (addr == `ADDR_LYC) ? rLYC :
-                       (addr == `ADDR_BGP) ? rBGP :
-                       (addr == `ADDR_OBP0) ? rOBP0 :
-                       (addr == `ADDR_OBP1) ? rOBP1 :
-                       (addr == `ADDR_WY) ? rWY :
-                       (addr == `ADDR_WX) ? rWX :
-                       (decode_tiledata) ? tilelowtmp :
-                       (decode_bgmap1) ? tileno :
-                       8'bzzzzzzzz :
+                       ((addr == `ADDR_LCDC) ? rLCDC :
+                        (addr == `ADDR_STAT) ? {rSTAT[7:3], (rLYC == posy) ? 1'b1 : 1'b0, mode} :
+                        (addr == `ADDR_SCY) ? rSCY :
+                        (addr == `ADDR_SCX) ? rSCX :
+                        (addr == `ADDR_LY) ? posy :
+                        (addr == `ADDR_LYC) ? rLYC :
+                        (addr == `ADDR_BGP) ? rBGP :
+                        (addr == `ADDR_OBP0) ? rOBP0 :
+                        (addr == `ADDR_OBP1) ? rOBP1 :
+                        (addr == `ADDR_WY) ? rWY :
+                        (addr == `ADDR_WX) ? rWX :
+                        (decode_tiledata && addr[0]) ? tilehigh :
+                        (decode_tiledata && ~addr[0]) ? tilelow :
+                        (decode_bgmap1) ? tileno :
+                        8'bzzzzzzzz) :
                8'bzzzzzzzz;
   
        always @(negedge clk)