ICache: Change cache_data to block RAM (yay!).

[firearm.git] / ICache.v

diff --git a/ICache.v b/ICache.v
index 2e28adfabd54e1a98c338332a6ef122439089000..dc26fdc4b52f469785d24e844702d3a60453bbeb 100644 (file)
--- 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
@@ -40,39 +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];
+       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)
-               if (rd_req && !cache_hit) begin
-                       if (bus_ready) begin    /* Started the fill, and we have data. */
-                               $display("CACHE FILL: rq adr %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
+       always @(posedge clk) begin
+               // 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