module chargen
  #(
    parameter CHAR_WIDTH=8,
    parameter CHAR_HEIGHT=8,
    parameter COLS=80,
    parameter ROWS=60)  
   (input  i_clk,
    input  i_rst,
    input  i_de,
    input  i_hsync,
    input  i_vsync,
    output o_r,
    output o_g,
    output o_b);

   reg [7:0]  fontrom [0:2047];
   reg [19:0] pos;
   reg [2:0]  font_row_offset;
   reg	      font_row_offset_lock;
   reg [7:0]  glyph_line;
   reg [11:0] cram_addr;
   reg [11:0] cram_addr_sol;
   reg [6:0]  line_counter;

   wire [7:0] glyph_line_wire;
   wire	      glyph_bit;
   wire [11:0] font_index;

   assign font_index = {cram_addr[7:0], font_row_offset};
   assign glyph_bit = glyph_line[7];
   assign o_r = glyph_bit;
   assign o_g = glyph_bit;
   assign o_b = cram_addr[0];   

   initial begin
      $readmemh("/Users/car/Projects/hope/font.hex", fontrom);
   end

   always @(posedge i_clk, posedge i_rst) begin
      if (i_rst) begin
	 glyph_line <= 0;
      end else begin
	 if (pos[2:0] == 7) begin
	    glyph_line <= fontrom[font_index];
	 end else if (i_de) begin
	    glyph_line <= (glyph_line << 1);
	 end
      end
   end // always @ (posedge i_clk, posedge i_rst)

   always @(posedge i_clk, posedge i_rst) begin
      if (i_rst) begin
	 cram_addr <= 0;
	 cram_addr_sol <= 0;
	 line_counter <= 0;
      end else if (i_hsync) begin
	 if (line_counter == 0) begin
	    cram_addr_sol <= cram_addr;
	    line_counter <= 0;
	 end else begin
	    cram_addr <= cram_addr_sol;
	    line_counter <= line_counter + 1;
	 end
      end else if (pos[2:0] == 7)
	cram_addr <= cram_addr + 1;
   end

   always @(posedge i_clk, posedge i_rst) begin
      if (i_rst) begin
	 pos <= 0;
	 font_row_offset <= 0;
	 font_row_offset_lock <= 0;
      end else begin
	 if (i_vsync) begin
	    pos <= 0;
	    font_row_offset <= 0;
	 end else if (i_de) begin
	    pos <= pos + 1;
	 end else begin
	    pos <= pos;

	    if (~font_row_offset_lock & i_hsync) begin
	       font_row_offset_lock <= 1;
	       font_row_offset <= font_row_offset + 1;
	    end else if (~i_hsync) begin
	       font_row_offset_lock <= 0;
	    end
	 end
      end
   end
endmodule