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// Dual ported RAM
// Addresses are byte-oriented, so botton 2 address bits are ignored.
// AWIDTH of 13 allows you to address 8K bytes.
// For Spartan 3, if the total RAM size is not a multiple of 8K then BRAM space is wasted
// RAM_SIZE parameter allows odd-sized RAMs, like 24K
module dpram32 #(parameter AWIDTH=15,
parameter RAM_SIZE=16384)
(input clk,
input [AWIDTH-1:0] adr1_i,
input [31:0] dat1_i,
output reg [31:0] dat1_o,
input we1_i,
input en1_i,
input [3:0] sel1_i,
input [AWIDTH-1:0] adr2_i,
input [31:0] dat2_i,
output reg [31:0] dat2_o,
input we2_i,
input en2_i,
input [3:0] sel2_i );
reg [7:0] ram0 [0:(RAM_SIZE/4)-1];
reg [7:0] ram1 [0:(RAM_SIZE/4)-1];
reg [7:0] ram2 [0:(RAM_SIZE/4)-1];
reg [7:0] ram3 [0:(RAM_SIZE/4)-1];
// This is how we used to size the RAM -->
// reg [7:0] ram3 [0:(1<<(AWIDTH-2))-1];
// Port 1
always @(posedge clk)
if(en1_i) dat1_o[31:24] <= ram3[adr1_i[AWIDTH-1:2]];
always @(posedge clk)
if(en1_i) dat1_o[23:16] <= ram2[adr1_i[AWIDTH-1:2]];
always @(posedge clk)
if(en1_i) dat1_o[15:8] <= ram1[adr1_i[AWIDTH-1:2]];
always @(posedge clk)
if(en1_i) dat1_o[7:0] <= ram0[adr1_i[AWIDTH-1:2]];
always @(posedge clk)
if(we1_i & en1_i & sel1_i[3])
ram3[adr1_i[AWIDTH-1:2]] <= dat1_i[31:24];
always @(posedge clk)
if(we1_i & en1_i & sel1_i[2])
ram2[adr1_i[AWIDTH-1:2]] <= dat1_i[23:16];
always @(posedge clk)
if(we1_i & en1_i & sel1_i[1])
ram1[adr1_i[AWIDTH-1:2]] <= dat1_i[15:8];
always @(posedge clk)
if(we1_i & en1_i & sel1_i[0])
ram0[adr1_i[AWIDTH-1:2]] <= dat1_i[7:0];
// Port 2
always @(posedge clk)
if(en2_i) dat2_o[31:24] <= ram3[adr2_i[AWIDTH-1:2]];
always @(posedge clk)
if(en2_i) dat2_o[23:16] <= ram2[adr2_i[AWIDTH-1:2]];
always @(posedge clk)
if(en2_i) dat2_o[15:8] <= ram1[adr2_i[AWIDTH-1:2]];
always @(posedge clk)
if(en2_i) dat2_o[7:0] <= ram0[adr2_i[AWIDTH-1:2]];
always @(posedge clk)
if(we2_i & en2_i & sel2_i[3])
ram3[adr2_i[AWIDTH-1:2]] <= dat2_i[31:24];
always @(posedge clk)
if(we2_i & en2_i & sel2_i[2])
ram2[adr2_i[AWIDTH-1:2]] <= dat2_i[23:16];
always @(posedge clk)
if(we2_i & en2_i & sel2_i[1])
ram1[adr2_i[AWIDTH-1:2]] <= dat2_i[15:8];
always @(posedge clk)
if(we2_i & en2_i & sel2_i[0])
ram0[adr2_i[AWIDTH-1:2]] <= dat2_i[7:0];
endmodule // dpram32
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