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`timescale 1 ns / 1 ps
// `define VERBOSE
// `define RANDOM_AXI_DELAYS
module testbench;
reg clk = 1;
reg resetn = 0;
wire trap;
always #5 clk = ~clk;
initial begin
repeat (100) @(posedge clk);
resetn <= 1;
end
wire mem_axi_awvalid;
reg mem_axi_awready = 0;
wire [31:0] mem_axi_awaddr;
wire [ 2:0] mem_axi_awprot;
wire mem_axi_wvalid;
reg mem_axi_wready = 0;
wire [31:0] mem_axi_wdata;
wire [ 3:0] mem_axi_wstrb;
reg mem_axi_bvalid = 0;
wire mem_axi_bready;
wire mem_axi_arvalid;
reg mem_axi_arready = 0;
wire [31:0] mem_axi_araddr;
wire [ 2:0] mem_axi_arprot;
reg mem_axi_rvalid = 0;
wire mem_axi_rready;
reg [31:0] mem_axi_rdata;
picorv32_axi uut (
.clk (clk ),
.resetn (resetn ),
.trap (trap ),
.mem_axi_awvalid(mem_axi_awvalid),
.mem_axi_awready(mem_axi_awready),
.mem_axi_awaddr (mem_axi_awaddr ),
.mem_axi_awprot (mem_axi_awprot ),
.mem_axi_wvalid (mem_axi_wvalid ),
.mem_axi_wready (mem_axi_wready ),
.mem_axi_wdata (mem_axi_wdata ),
.mem_axi_wstrb (mem_axi_wstrb ),
.mem_axi_bvalid (mem_axi_bvalid ),
.mem_axi_bready (mem_axi_bready ),
.mem_axi_arvalid(mem_axi_arvalid),
.mem_axi_arready(mem_axi_arready),
.mem_axi_araddr (mem_axi_araddr ),
.mem_axi_arprot (mem_axi_arprot ),
.mem_axi_rvalid (mem_axi_rvalid ),
.mem_axi_rready (mem_axi_rready ),
.mem_axi_rdata (mem_axi_rdata )
);
reg [31:0] memory [0:64*1024/4-1];
initial $readmemh("firmware/firmware.hex", memory);
reg [63:0] xorshift64_state = 64'd88172645463325252;
task xorshift64_next;
begin
// see page 4 of Marsaglia, George (July 2003). "Xorshift RNGs". Journal of Statistical Software 8 (14).
xorshift64_state = xorshift64_state ^ (xorshift64_state << 13);
xorshift64_state = xorshift64_state ^ (xorshift64_state >> 7);
xorshift64_state = xorshift64_state ^ (xorshift64_state << 17);
end
endtask
reg [2:0] fast_axi_transaction = ~0;
reg [4:0] delay_axi_transaction = 0;
`ifdef RANDOM_AXI_DELAYS
always @(posedge clk) begin
xorshift64_next;
{fast_axi_transaction, delay_axi_transaction} <= xorshift64_state;
end
`endif
reg latched_raddr_en = 0;
reg latched_waddr_en = 0;
reg latched_wdata_en = 0;
reg fast_raddr = 0;
reg fast_waddr = 0;
reg fast_wdata = 0;
reg [31:0] latched_raddr;
reg [31:0] latched_waddr;
reg [31:0] latched_wdata;
reg [ 3:0] latched_wstrb;
reg latched_rinsn;
always @(posedge clk) begin
mem_axi_arready <= 0;
mem_axi_awready <= 0;
mem_axi_wready <= 0;
fast_raddr <= 0;
fast_waddr <= 0;
fast_wdata <= 0;
if (mem_axi_rvalid && mem_axi_rready) begin
mem_axi_rvalid <= 0;
end
if (mem_axi_bvalid && mem_axi_bready) begin
mem_axi_bvalid <= 0;
end
if (mem_axi_arvalid && mem_axi_arready && !fast_raddr) begin
latched_raddr = mem_axi_araddr;
latched_rinsn = mem_axi_arprot[2];
latched_raddr_en = 1;
end
if (mem_axi_awvalid && mem_axi_awready && !fast_waddr) begin
latched_waddr = mem_axi_awaddr;
latched_waddr_en = 1;
end
if (mem_axi_wvalid && mem_axi_wready && !fast_wdata) begin
latched_wdata = mem_axi_wdata;
latched_wstrb = mem_axi_wstrb;
latched_wdata_en = 1;
end
if (mem_axi_arvalid && !(latched_raddr_en || fast_raddr) && !delay_axi_transaction[0]) begin
mem_axi_arready <= 1;
if (fast_axi_transaction[0]) begin
fast_raddr <= 1;
latched_raddr = mem_axi_araddr;
latched_rinsn = mem_axi_arprot[2];
latched_raddr_en = 1;
end
end
if (mem_axi_awvalid && !(latched_waddr_en || fast_waddr) && !delay_axi_transaction[1]) begin
mem_axi_awready <= 1;
if (fast_axi_transaction[1]) begin
fast_waddr <= 1;
latched_waddr = mem_axi_awaddr;
latched_waddr_en = 1;
end
end
if (mem_axi_wvalid && !(latched_wdata_en || fast_wdata) && !delay_axi_transaction[2]) begin
mem_axi_wready <= 1;
if (fast_axi_transaction[2]) begin
fast_wdata <= 1;
latched_wdata = mem_axi_wdata;
latched_wstrb = mem_axi_wstrb;
latched_wdata_en = 1;
end
end
if (!mem_axi_rvalid && latched_raddr_en && !delay_axi_transaction[3]) begin
`ifdef VERBOSE
$display("RD: ADDR=%08x DATA=%08x%s", latched_raddr, memory[latched_raddr >> 2], latched_rinsn ? " INSN" : "");
`endif
if (latched_raddr < 64*1024) begin
mem_axi_rdata <= memory[latched_raddr >> 2];
mem_axi_rvalid <= 1;
latched_raddr_en = 0;
end else begin
$display("OUT-OF-BOUNDS MEMORY READ FROM %08x", latched_raddr);
$finish;
end
end
if (!mem_axi_bvalid && latched_waddr_en && latched_wdata_en && !delay_axi_transaction[4]) begin
`ifdef VERBOSE
$display("WR: ADDR=%08x DATA=%08x STRB=%04b", latched_waddr, latched_wdata, latched_wstrb);
`endif
if (latched_waddr < 64*1024) begin
if (latched_wstrb[0]) memory[latched_waddr >> 2][ 7: 0] <= latched_wdata[ 7: 0];
if (latched_wstrb[1]) memory[latched_waddr >> 2][15: 8] <= latched_wdata[15: 8];
if (latched_wstrb[2]) memory[latched_waddr >> 2][23:16] <= latched_wdata[23:16];
if (latched_wstrb[3]) memory[latched_waddr >> 2][31:24] <= latched_wdata[31:24];
end else
if (latched_waddr == 32'h1000_0000) begin
`ifdef VERBOSE
if (32 <= latched_wdata && latched_wdata < 128)
$display("OUT: '%c'", latched_wdata);
else
$display("OUT: %3d", latched_wdata);
`else
$write("%c", latched_wdata);
$fflush();
`endif
end else begin
$display("OUT-OF-BOUNDS MEMORY WRITE TO %08x", latched_waddr);
$finish;
end
mem_axi_bvalid <= 1;
latched_waddr_en = 0;
latched_wdata_en = 0;
end
end
initial begin
$dumpfile("testbench.vcd");
$dumpvars(0, testbench);
repeat (1000000) @(posedge clk);
$display("TIMEOUT");
$finish;
end
always @(posedge clk) begin
if (resetn && trap) begin
repeat (10) @(posedge clk);
$display("TRAP");
$finish;
end
end
endmodule
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