X-Git-Url: http://git.joshuawise.com/firearm.git/blobdiff_plain/8b417b452a3b1f51f7cec4d2daed4c902607f000..ba1c1a27e6fb12882b59cdbd80147a4c12a675b4:/ICache.v diff --git a/ICache.v b/ICache.v index 8106259..dc26fdc 100644 --- a/ICache.v +++ b/ICache.v @@ -4,24 +4,33 @@ module ICache( input clk, /* ARM core interface */ - input [31:0] rd_addr, - input rd_req, - output reg rd_wait, - output reg [31:0] rd_data, + input [31:0] ic__rd_addr_0a, + input ic__rd_req_0a, + output wire ic__rd_wait_0a, + output wire [31:0] ic__rd_data_1a, /* bus interface */ - output wire bus_req, - input bus_ack, - output reg [31:0] bus_addr, - input [31:0] bus_rdata, + output wire bus_req, + input bus_ack, + output reg [31:0] bus_addr, + input [31:0] bus_rdata, output wire [31:0] bus_wdata, - output reg bus_rd, - output wire bus_wr, - input bus_ready); + output reg bus_rd, + output wire bus_wr, + input bus_ready); assign bus_wr = 0; assign bus_wdata = 0; + wire [31:0] rd_addr_0a; + wire rd_req_0a; + reg rd_wait_0a; + reg [31:0] rd_data_1a; + assign ic__rd_wait_0a = rd_wait_0a; + assign ic__rd_data_1a = rd_data_1a; + assign rd_addr_0a = ic__rd_addr_0a; + assign rd_req_0a = ic__rd_req_0a; + /* [31 tag 10] [9 cache index 6] [5 data index 0] * so the data index is 6 bits long * so the cache index is 4 bits long @@ -30,9 +39,9 @@ module ICache( reg cache_valid [15:0]; reg [21:0] cache_tags [15:0]; - reg [31:0] cache_data [15:0 /* line */] [15:0 /* word */]; + reg [31:0] cache_data [255:0 /* {line, word} */]; //synthesis attribute ram_style of cache_data is block - reg [4:0] i; + integer i; initial for (i = 0; i < 16; i = i + 1) begin @@ -40,45 +49,47 @@ module ICache( cache_tags[i[3:0]] = 0; end - wire [5:0] rd_didx = rd_addr[5:0]; - wire [3:0] rd_didx_word = rd_didx[5:2]; - wire [3:0] rd_idx = rd_addr[9:6]; - wire [21:0] rd_tag = rd_addr[31:10]; - - reg [31:0] prev_rd_addr = 32'hFFFFFFFF; + wire [5:0] rd_didx_0a = rd_addr_0a[5:0]; + wire [3:0] rd_didx_word_0a = rd_didx_0a[5:2]; + wire [3:0] rd_idx_0a = rd_addr_0a[9:6]; + wire [21:0] rd_tag_0a = rd_addr_0a[31:10]; - wire cache_hit = cache_valid[rd_idx] && (cache_tags[rd_idx] == rd_tag); + reg [31:0] rd_addr_1a = 32'hFFFFFFFF; - always @(*) begin /* XXX does this work nowadays? */ - rd_wait = rd_req && !cache_hit; - rd_data = cache_data[rd_idx][rd_didx_word]; - end + wire cache_hit_0a = cache_valid[rd_idx_0a] && (cache_tags[rd_idx_0a] == rd_tag_0a); - reg [3:0] cache_fill_pos = 0; - assign bus_req = rd_req && !cache_hit; /* xxx, needed for Verilator */ + reg [3:0] cache_fill_pos_0a = 0; + assign bus_req = rd_req_0a && !cache_hit_0a; /* xxx, needed for Verilator */ always @(*) - if (rd_req && !cache_hit && bus_ack) begin - bus_addr = {rd_addr[31:6], cache_fill_pos[3:0], 2'b00 /* reads are 32-bits */}; + if (rd_req_0a && !cache_hit_0a && bus_ack) begin + bus_addr = {rd_addr_0a[31:6], cache_fill_pos_0a[3:0], 2'b00 /* reads are 32-bits */}; bus_rd = 1; end else begin bus_addr = 0; bus_rd = 0; end + + always @(*) begin + rd_wait_0a = rd_req_0a && !cache_hit_0a; + end always @(posedge clk) begin - prev_rd_addr <= {rd_addr[31:6], 6'b0}; - if (cache_fill_pos != 0 && ((prev_rd_addr != {rd_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. */ - $display("ICACHE: FILL: rd addr %08x; bus addr %08x; bus data %08x", rd_addr, bus_addr, bus_rdata); - cache_data[rd_idx][cache_fill_pos] <= bus_rdata; - cache_fill_pos <= cache_fill_pos + 1; - if (cache_fill_pos == 15) begin /* Done? */ - cache_tags[rd_idx] <= rd_tag; - cache_valid[rd_idx] <= 1; - end - end + // Do the actual read. + rd_data_1a <= cache_data[{rd_idx_0a,rd_didx_word_0a}]; + + rd_addr_1a <= {rd_addr_0a[31:6], 6'b0}; + if (cache_fill_pos_0a != 0 && ((rd_addr_1a != {rd_addr_0a[31:6], 6'b0}) || cache_hit_0a)) /* If this wasn't from the same line, or we've moved on somehow, reset the fill circuitry. */ + cache_fill_pos_0a <= 0; + else if (rd_req_0a && !cache_hit_0a && bus_ack && bus_ready) begin + $display("ICACHE: FILL: rd addr %08x; bus addr %08x; bus data %08x", rd_addr_0a, bus_addr, bus_rdata); + cache_data[{rd_idx_0a,cache_fill_pos_0a}] <= bus_rdata; + cache_fill_pos_0a <= cache_fill_pos_0a + 1; + if (cache_fill_pos_0a == 15) begin /* Done? */ + cache_tags[rd_idx_0a] <= rd_tag_0a; + cache_valid[rd_idx_0a] <= 1; + $display("ICACHE: Fill complete for line %x, tag %x", rd_idx_0a, rd_tag_0a); + end else + cache_valid[rd_idx_0a] <= 0; end end endmodule