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[fpga-games] / galaxian / src / mc_missile.v

//===============================================================================\r
// FPGA MOONCRESTA VIDEO-MISSILE\r
//\r
// Version : 2.00\r
//\r
// Copyright(c) 2004 Katsumi Degawa , All rights reserved\r
//\r
// Important !\r
//\r
// This program is freeware for non-commercial use. \r
// An author does no guarantee about this program.\r
// You can use this under your own risk.\r
//\r
// 2004- 9-22 The problem which missile didn't sometimes come out from was improved.\r
//================================================================================\r
\r
\r
module mc_missile(\r
\r
I_CLK_18M,\r
I_CLK_6M,\r
I_C_BLn_X,\r
I_MLDn,\r
I_SLDn,\r
I_HPOS,\r
\r
O_MISSILEn,\r
O_SHELLn\r
\r
);\r
\r
input  I_CLK_6M,I_CLK_18M;\r
input  I_C_BLn_X;\r
input  I_MLDn;\r
input  I_SLDn;\r
input  [7:0]I_HPOS;\r
\r
output O_MISSILEn;\r
output O_SHELLn;\r
\r
reg    [7:0]W_45R_Q;\r
\r
always@(posedge I_CLK_6M)\r
begin\r
   if(I_MLDn==1'b0)\r
      W_45R_Q <= I_HPOS;\r
   else begin\r
      if(I_C_BLn_X)\r
         W_45R_Q <= W_45R_Q +1;\r
      else\r
         W_45R_Q <= W_45R_Q ;\r
   end\r
end\r
\r
reg    W_5P1_Q;\r
reg    W_5P1_CLK; \r
\r
always@(posedge I_CLK_18M)\r
   W_5P1_CLK <= ~((&W_45R_Q[7:2])&W_5P1_Q);\r
\r
always@(posedge W_5P1_CLK or negedge I_MLDn)\r
begin\r
   if(I_MLDn==1'b0)\r
      W_5P1_Q <= 1'b1;\r
   else\r
      W_5P1_Q <= 1'b0;\r
end\r
\r
assign O_MISSILEn = W_5P1_CLK;\r
\r
reg    [7:0]W_45S_Q;\r
always@(posedge I_CLK_6M)\r
begin\r
   if(I_SLDn==1'b0)\r
      W_45S_Q <= I_HPOS;\r
   else begin\r
      if(I_C_BLn_X)\r
         W_45S_Q <= W_45S_Q +1;\r
      else\r
         W_45S_Q <= W_45S_Q ;\r
   end\r
end\r
\r
reg    W_5P2_Q;\r
reg    W_5P2_CLK;\r
\r
always@(posedge I_CLK_18M)\r
   W_5P2_CLK <= ~((&W_45S_Q[7:2])&W_5P2_Q);\r
\r
always@(posedge W_5P2_CLK or negedge I_SLDn)\r
begin\r
   if(I_SLDn==1'b0)\r
      W_5P2_Q <= 1'b1;\r
   else\r
      W_5P2_Q <= 1'b0;\r
end\r
\r
assign O_SHELLn = W_5P2_CLK;\r
\r
\r
endmodule