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|
`timescale 1 ns / 1 ps
`undef VERBOSE_MEM
//`undef WRITE_VCD
`undef MEM8BIT
// define the size of our ROM
// simulates ROM by suppressing writes below this address
`define ROM_SIZE 32'h0001_00FF
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_valid;
wire mem_instr;
reg mem_ready;
wire [31:0] mem_addr;
wire [31:0] mem_wdata;
wire [3:0] mem_wstrb;
reg [31:0] mem_rdata;
`include "firmware_dbg.v"
picorv32 #(
.COMPRESSED_ISA(1),
.PROGADDR_RESET(32'h100)
) uut (
.clk (clk ),
.resetn (resetn ),
.trap (trap ),
.mem_valid (mem_valid ),
.mem_instr (mem_instr ),
.mem_ready (mem_ready ),
.mem_addr (mem_addr ),
.mem_wdata (mem_wdata ),
.mem_wstrb (mem_wstrb ),
.mem_rdata (mem_rdata )
);
localparam MEM_SIZE = 4*1024*1024;
`ifdef MEM8BIT
reg [7:0] memory [0:MEM_SIZE-1];
initial
$readmemh("firmware.hex", memory);
end
`else
reg [31:0] memory [0:MEM_SIZE/4-1];
integer x;
// simulate hardware assist of clearing RAM and copying ROM data into
// memory
initial
begin
// clear memory
for (x=0; x<MEM_SIZE/4; x=x+1) memory[x] = 0;
// load rom contents
$readmemh("firmware32.hex", memory);
// copy .data section
for (x=0; x<(`C_SYM__BSS_START - `C_SYM___GLOBAL_POINTER); x=x+4)
memory[(`C_SYM___GLOBAL_POINTER+x)/4] = memory[(`C_SYM__DATA_LMA+x)/4];
end
`endif
always @(posedge clk) begin
mem_ready <= 0;
if (mem_valid && !mem_ready) begin
mem_ready <= 1;
mem_rdata <= 'bx;
case (1)
mem_addr < MEM_SIZE: begin
`ifdef MEM8BIT
if (|mem_wstrb) begin
if (mem_wstrb[0]) memory[mem_addr + 0] <= mem_wdata[ 7: 0];
if (mem_wstrb[1]) memory[mem_addr + 1] <= mem_wdata[15: 8];
if (mem_wstrb[2]) memory[mem_addr + 2] <= mem_wdata[23:16];
if (mem_wstrb[3]) memory[mem_addr + 3] <= mem_wdata[31:24];
end else begin
mem_rdata <= {memory[mem_addr+3], memory[mem_addr+2], memory[mem_addr+1], memory[mem_addr]};
end
`else
if ((|mem_wstrb) && (mem_addr >= `ROM_SIZE)) begin
if (mem_wstrb[0]) memory[mem_addr >> 2][ 7: 0] <= mem_wdata[ 7: 0];
if (mem_wstrb[1]) memory[mem_addr >> 2][15: 8] <= mem_wdata[15: 8];
if (mem_wstrb[2]) memory[mem_addr >> 2][23:16] <= mem_wdata[23:16];
if (mem_wstrb[3]) memory[mem_addr >> 2][31:24] <= mem_wdata[31:24];
end else begin
mem_rdata <= memory[mem_addr >> 2];
end
`endif
end
mem_addr == 32'h 1000_0000: begin
$write("%c", mem_wdata[7:0]);
end
endcase
end
if (mem_valid && mem_ready) begin
`ifdef FIRMWARE_DEBUG_ADDR
firmware_dbg(mem_addr);
`endif
if ((mem_wstrb == 4'h0) && (mem_rdata === 32'bx)) $display("READ FROM UNITIALIZED ADDR=%x", mem_addr);
`ifdef VERBOSE_MEM
if (|mem_wstrb)
$display("WR: ADDR=%x DATA=%x MASK=%b", mem_addr, mem_wdata, mem_wstrb);
else
$display("RD: ADDR=%x DATA=%x%s", mem_addr, mem_rdata, mem_instr ? " INSN" : "");
`endif
if (^mem_addr === 1'bx ||
(mem_wstrb[0] && ^mem_wdata[ 7: 0] == 1'bx) ||
(mem_wstrb[1] && ^mem_wdata[15: 8] == 1'bx) ||
(mem_wstrb[2] && ^mem_wdata[23:16] == 1'bx) ||
(mem_wstrb[3] && ^mem_wdata[31:24] == 1'bx)) begin
$display("CRITICAL UNDEF MEM TRANSACTION");
$finish;
end
end
end
`ifdef WRITE_VCD
initial begin
$dumpfile("testbench.vcd");
$dumpvars(0, testbench);
end
`endif
always @(posedge clk) begin
if (resetn && trap) begin
repeat (10) @(posedge clk);
$display("TRAP");
$finish;
end
end
endmodule
|
