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			110 lines
		
	
	
	
		
			2.7 KiB
		
	
	
	
		
			Verilog
		
	
	
	
	
	
			
		
		
	
	
			110 lines
		
	
	
	
		
			2.7 KiB
		
	
	
	
		
			Verilog
		
	
	
	
	
	
| module bram_tb #(
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| 	parameter ABITS = 8, DBITS = 8,
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| 	parameter INIT_ADDR = 0, INIT_DATA = 0
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| );
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| 	reg clk;
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| 	reg [ABITS-1:0] WR_ADDR;
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| 	reg [DBITS-1:0] WR_DATA;
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| 	reg WR_EN;
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| 	reg [ABITS-1:0] RD_ADDR;
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| 	wire [DBITS-1:0] RD_DATA;
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| 
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| 	bram uut  (
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| 		.clk    (clk    ),
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| 		.WR_ADDR(WR_ADDR),
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| 		.WR_DATA(WR_DATA),
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| 		.WR_EN  (WR_EN  ),
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| 		.RD_ADDR(RD_ADDR),
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| 		.RD_DATA(RD_DATA)
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| 	);
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| 
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| 	reg [63:0] xorshift64_state = 64'd88172645463325252 ^ (ABITS << 24) ^ (DBITS << 16);
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| 
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| 	task xorshift64_next;
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| 		begin
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| 		// see page 4 of Marsaglia, George (July 2003). "Xorshift RNGs". Journal of Statistical Software 8 (14).
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| 		xorshift64_state = xorshift64_state ^ (xorshift64_state << 13);
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| 		xorshift64_state = xorshift64_state ^ (xorshift64_state >>  7);
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| 		xorshift64_state = xorshift64_state ^ (xorshift64_state << 17);
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| 		end
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| 	endtask
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| 
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| 	reg [ABITS-1:0] randaddr1;
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| 	reg [ABITS-1:0] randaddr2;
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| 	reg [ABITS-1:0] randaddr3;
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| 
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| 	function [31:0] getaddr(input [3:0] n);
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| 		begin
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| 			case (n)
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| 				0: getaddr = 0;
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| 				1: getaddr = 2**ABITS-1;
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| 				2: getaddr = 'b101 << (ABITS / 3);
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| 				3: getaddr = 'b101 << (2*ABITS / 3);
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| 				4: getaddr = 'b11011 << (ABITS / 4);
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| 				5: getaddr = 'b11011 << (2*ABITS / 4);
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| 				6: getaddr = 'b11011 << (3*ABITS / 4);
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| 				7: getaddr = randaddr1;
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| 				8: getaddr = randaddr2;
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| 				9: getaddr = randaddr3;
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| 				default: begin
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| 					getaddr = 1 << (2*n-16);
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| 					if (!getaddr) getaddr = xorshift64_state;
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| 				end
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| 			endcase
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| 		end
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| 	endfunction
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| 
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| 	reg [DBITS-1:0] memory [0:2**ABITS-1];
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| 	reg [DBITS-1:0] expected_rd, expected_rd_masked;
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| 
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| 	event error;
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| 	integer i, j;
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| 
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| 	initial begin
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| 		// $dumpfile("testbench.vcd");
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| 		// $dumpvars(0, bram_tb);
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| 
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| 		memory[INIT_ADDR] <= INIT_DATA;
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| 
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| 		xorshift64_next;
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| 		xorshift64_next;
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| 		xorshift64_next;
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| 		xorshift64_next;
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| 
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| 		randaddr1 = xorshift64_state;
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| 		xorshift64_next;
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| 
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| 		randaddr2 = xorshift64_state;
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| 		xorshift64_next;
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| 
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| 		randaddr3 = xorshift64_state;
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| 		xorshift64_next;
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| 
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| 		clk <= 0;
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| 		for (i = 0; i < 512; i = i+1) begin
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| 			WR_DATA = xorshift64_state;
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| 			xorshift64_next;
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| 
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| 			WR_ADDR = getaddr(i < 256 ? i[7:4] : xorshift64_state[63:60]);
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| 			xorshift64_next;
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| 
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| 			RD_ADDR = i == 0 ? INIT_ADDR : getaddr(i < 256 ? i[3:0] : xorshift64_state[59:56]);
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| 			WR_EN = xorshift64_state[55] && ((WR_ADDR & 'hff) != (RD_ADDR & 'hff));
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| 			xorshift64_next;
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| 
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| 			#1; clk <= 1;
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| 			#1; clk <= 0;
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| 
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| 			expected_rd = memory[RD_ADDR];
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| 			if (WR_EN) memory[WR_ADDR] = WR_DATA;
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| 
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| 			for (j = 0; j < DBITS; j = j+1)
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| 				expected_rd_masked[j] = expected_rd[j] !== 1'bx ? expected_rd[j] : RD_DATA[j];
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| 
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| 			$display("#OUT# %3d | WA=%x WD=%x WE=%x | RA=%x RD=%x (%x) | %s",
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| 					i, WR_ADDR, WR_DATA, WR_EN, RD_ADDR, RD_DATA, expected_rd,
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| 					expected_rd_masked === RD_DATA ? "ok" : "ERROR");
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| 			if (expected_rd_masked !== RD_DATA) begin -> error; end
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| 		end
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| 	end
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| endmodule
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