1 files changed, 85 insertions, 0 deletions
diff --git a/source/cam.v b/source/cam.v
new file mode 100644
index 0000000..082194a
--- /dev/null
+++ b/source/cam.v
@@ -0,0 +1,85 @@
+/* 
+ * 	cam.v
+ * 	
+ *   Copyright (C) 2018, 2019 Mind Chasers Inc.
+ *
+ *   Licensed under the Apache License, Version 2.0 (the "License");
+ *   you may not use this file except in compliance with the License.
+ *   You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *   Unless required by applicable law or agreed to in writing, software
+ *   distributed under the License is distributed on an "AS IS" BASIS,
+ *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *   See the License for the specific language governing permissions and
+ *   limitations under the License.
+ *	
+ *	function: single cycle, parameterized CAM 
+ *	
+ */
+ 
+`timescale 1ns /10ps
+
+module cam #(parameter DEPTH = 4,
+			parameter DEPTHW = 2,
+			parameter WIDTH = 32)
+(
+	input	rstn,
+	input	clk,
+	
+	// input for programming
+	input 	sel,
+	input 	we,
+	input 	[DEPTHW+1:0] addr,		// add two bits for the byte selects
+	input 	[7:0]	d_in,
+	
+	input 	search,
+	input	[(WIDTH-1):0]search_address,
+	
+	// output
+	output reg match
+);
+	
+	reg [(WIDTH-1):0] content[0:DEPTH-1];
+	reg [(DEPTH-1):0] valid;
+	integer i,j;
+	
+	// Program the CAM
+	always @(posedge clk, negedge rstn)
+		if( !rstn ) begin
+			for (i=0; i < DEPTH; i=i+1)	begin
+				content[i] <= 32'h0;
+				valid[i] <= 1'b0;
+			end
+		end
+		else if ( we && sel )
+			if (addr[1:0] == 2'b00) begin
+				content[addr[DEPTHW+1:2]][7:0] <= d_in;
+				valid[addr[DEPTHW+1:2]] <= 1'b1;
+			end
+			else if (addr[1:0] == 2'b01) begin
+				content[addr[DEPTHW+1:2]][15:8] <= d_in;
+				valid[addr[DEPTHW+1:2]] <= 1'b1;
+			end
+			else if (addr[1:0] == 2'b10) begin
+				content[addr[DEPTHW+1:2]][23:16] <= d_in;
+				valid[addr[DEPTHW+1:2]] <= 1'b1;
+			end
+			else if (addr[1:0] == 2'b11) begin
+				content[addr[DEPTHW+1:2]][31:24] <= d_in;
+				valid[addr[DEPTHW+1:2]] <= 1'b1;
+			end
+		
+	// search the CAM
+	always @(posedge clk) begin
+		match <= 1'b0;
+		for (j=0; j < DEPTH; j=j+1)	begin
+			if (search && valid[j] && search_address == content[j])
+				match <= 1'b1;
+
+		end
+	end
+	
+	
+endmodule