ROM的一种写法

 
module mr_rom_pll_valuemask_8bpc #(
parameter NUMBER_OF_MIF_RANGE = 6,
parameter ROM_DEPTH_FOR_EACH_MIF_RANGE = 7,
parameter ROM_SIZE = 32,
parameter TOTAL_ROM_DEPTH = 42, // 6*7
parameter ADDR_WIDTH = 6 // alt_clogb2(42)
) (
input wire clock,
input wire [ADDR_WIDTH-1:0] addr_ptr,
output wire [ROM_SIZE-1:0] rdata_out
);
 
reg [ROM_SIZE-1:0] ROM [0:TOTAL_ROM_DEPTH-1];
wire [ROM_SIZE-1:0] DATAA = {ROM_SIZE{1'b0}};
wire [ADDR_WIDTH-1:0] RADDR;
 
initial begin
// FIELD_VALMASK
// ROM OFFSET 0 (25MHz - 50MHz)
ROM[0] <= 32'h00000F0F; // m 30
ROM[1] <= 32'h00010000; // n 1
ROM[2] <= 32'h00000303; // c0 6
ROM[3] <= 32'h00001E1E; // c1 60
ROM[4] <= 32'h00001E1E; // c2 60
ROM[5] <= 32'h00000010; // cp
ROM[6] <= 32'h00000100; // bw
// ROM OFFSET 1 (51MHz - 70MHz)
ROM[7] <= 32'h00000A0A; // m 20
ROM[8] <= 32'h00010000; // n 1
ROM[9] <= 32'h00000202; // c0 4
ROM[10] <= 32'h00001414; // c1 40
ROM[11] <= 32'h00001414; // c2 40
ROM[12] <= 32'h0000000B; // cp
ROM[13] <= 32'h000000C0; // bw
// ROM OFFSET 2 (71MHz - 100MHz)
ROM[14] <= 32'h00000505; // m 10
ROM[15] <= 32'h00010000; // n 1
ROM[16] <= 32'h00000101; // c0 2
ROM[17] <= 32'h00000A0A; // c1 20
ROM[18] <= 32'h00000A0A; // c2 20
ROM[19] <= 32'h00000010; // cp
ROM[20] <= 32'h000000C0; // bw
// ROM OFFSET 3 (101MHz - 170MHz)
ROM[21] <= 32'h00000404; // m 8
ROM[22] <= 32'h00010000; // n 1
ROM[23] <= 32'h00000404; // c0 8
ROM[24] <= 32'h00000808; // c1 16
ROM[25] <= 32'h00000808; // c2 16
ROM[26] <= 32'h00000010; // cp
ROM[27] <= 32'h000000C0; // bw
// ROM OFFSET 4 (171MHz - 340MHz)
ROM[28] <= 32'h00000202; // m 4
ROM[29] <= 32'h00010000; // n 1
ROM[30] <= 32'h00000202; // c0 4
ROM[31] <= 32'h00000404; // c1 8
ROM[32] <= 32'h00000404; // c2 8
ROM[33] <= 32'h00000010; // cp
ROM[34] <= 32'h000000C0; // bw
// ROM OFFSET 5 (85.25MHz - 150MHz) - 2.0
ROM[35] <= 32'h00000404; // m 8
ROM[36] <= 32'h00010000; // n 1
ROM[37] <= 32'h00000101; // c0 2
ROM[38] <= 32'h00000202; // c1 4
ROM[39] <= 32'h00000202; // c2 4
ROM[40] <= 32'h00000010; // cp
ROM[41] <= 32'h000000C0; // bw
// Set the rest to all zeros
ROM[42] <= 32'h00000000;
ROM[43] <= 32'h00000000;
ROM[44] <= 32'h00000000;
ROM[45] <= 32'h00000000;
ROM[46] <= 32'h00000000;
ROM[47] <= 32'h00000000;
ROM[48] <= 32'h00000000;
ROM[49] <= 32'h00000000;
ROM[50] <= 32'h00000000;
ROM[51] <= 32'h00000000;
ROM[52] <= 32'h00000000;
ROM[53] <= 32'h00000000;
ROM[54] <= 32'h00000000;
ROM[55] <= 32'h00000000;
ROM[56] <= 32'h00000000;
ROM[57] <= 32'h00000000;
ROM[58] <= 32'h00000000;
ROM[59] <= 32'h00000000;
ROM[60] <= 32'h00000000;
ROM[61] <= 32'h00000000;
ROM[62] <= 32'h00000000;
ROM[63] <= 32'h00000000;
end
 
// write is unused
wire [ADDR_WIDTH-1:0] ADDRA = {ADDR_WIDTH{1'b0}};
wire WEA = 1'b0;
always @ (posedge clock)
begin
if (WEA) begin
ROM[ADDRA] <= DATAA;
end
end
 
assign RADDR = addr_ptr;
 
reg [ROM_SIZE-1:0] RDATA;
always @ (posedge clock)
begin
RDATA <= ROM[RADDR];
end
 
assign rdata_out = RDATA;
 
endmodule