wire [3:0] idx = addr[9:6];
wire [21:0] tag = addr[31:10];
+ reg [31:0] prev_addr = 32'hFFFFFFFF;
+
wire cache_hit = cache_valid[idx] && (cache_tags[idx] == tag);
always @(*) begin
rw_wait = (rd_req && !cache_hit) || (wr_req && (!bus_ack || !bus_ready));
rd_data = cache_data[idx][didx_word];
+ if (!rw_wait)
+ $display("DCACHE: READ COMPLETE: Addr %08x, data %08x", addr, rd_data);
end
reg [3:0] cache_fill_pos = 0;
assign bus_req = (rd_req && !cache_hit) || wr_req;
always @(*)
+ begin
+ bus_rd = 0;
+ bus_wr = 0;
+ bus_addr = 0;
+ bus_wdata = 0;
if (rd_req && !cache_hit && bus_ack) begin
bus_addr = {addr[31:6], cache_fill_pos[3:0], 2'b00 /* reads are 32-bits */};
bus_rd = 1;
end else if (wr_req && bus_ack) begin
+ $display("DCACHE: WRITE REQUEST: Addr %08x, data %08x", addr, wr_data);
bus_addr = addr;
bus_wr = 1;
bus_wdata = wr_data;
- end else begin
- bus_addr = 0;
- bus_rd = 0;
end
+ end
- always @(posedge clk)
- if (rd_req && !cache_hit) begin
+ always @(posedge clk) begin
+ prev_addr <= {addr[31:6], 6'b0};
+ if (rd_req && (cache_fill_pos != 0) && ((prev_addr != {addr[31:6], 6'b0}) || cache_hit)) /* If this wasn't from the same line, or we've moved on somehow, reset the fill circuitry. */
+ cache_fill_pos <= 0;
+ else if (rd_req && !cache_hit) begin
if (bus_ready) begin /* Started the fill, and we have data. */
cache_data[idx][cache_fill_pos] <= bus_rdata;
cache_fill_pos <= cache_fill_pos + 1;
end
end else if (wr_req && cache_hit)
cache_data[idx][addr[5:2]] = wr_data;
+ end
endmodule