Add chip enable correctness for CellularRAM.

[firearm.git] / Fetch.v

diff --git a/Fetch.v b/Fetch.v
index 3b6d9c57f9f5f090884e752ef0fdb68faa96263f..bc2175cc90994ccb015ed8b9d37da9c0067023a4 100644 (file)
--- a/Fetch.v
+++ b/Fetch.v
@@ -1,48 +1,70 @@
 module Fetch(
 module Fetch(

-       input clk,
-       input Nrst,
-       
-       output wire [31:0] rd_addr,
-       output wire rd_req,
-       input rd_wait,
-       input [31:0] rd_data,
-       
-       input stall,
-       input jmp,
-       input [31:0] jmppc,
-       output reg bubble = 1,
-       output reg [31:0] insn = 0,
-       output reg [31:0] pc = 0);
-
-       reg [31:0] prevpc;
-       reg [31:0] nextpc;
-       initial
-               prevpc = 32'hFFFFFFFC;  /* ugh... the first pc we request will be this +4 */
-       always @(negedge Nrst)
-               prevpc <= 32'hFFFFFFFC;
-
-       always @(*)     
+       input              clk,
+       input              Nrst,
+       
+       output wire [31:0] ic__rd_addr_0a,
+       output wire        ic__rd_req_0a,
+       input              ic__rd_wait_0a,
+       input       [31:0] ic__rd_data_1a,
+       
+       input              stall_0a,
+       input              jmp_0a,
+       input       [31:0] jmppc_0a,
+       output reg         bubble_1a = 1,
+       output reg  [31:0] insn_1a = 0,
+       output reg  [31:0] pc_1a = 32'hFFFFFFFC);
+       
+       reg qjmp = 0;   /* A jump has been queued up while we were waiting. */
+       reg [31:0] qjmppc;
+       always @(posedge clk or negedge Nrst)

                if (!Nrst)
                if (!Nrst)

-                       nextpc = 32'hFFFFFFFC;
-               else if (stall) /* don't change any internal state */
-                       nextpc = prevpc;
-               else if (jmp)
-                       nextpc = jmppc;
+                       qjmp <= 0;
+               else if ((ic__rd_wait_0a || stall_0a) && jmp_0a)
+                       {qjmp,qjmppc} <= {jmp_0a, jmppc_0a};
+               else if (!ic__rd_wait_0a && !stall_0a && qjmp)  /* It has already been intoed. */
+                       {qjmp,qjmppc} <= {1'b0, 32'hxxxxxxxx};
+       
+       reg [31:0] reqpc_0a;
+       
+       /* Output latch logic */
+       reg [31:0] insn_2a;
+       reg stall_1a;
+       always @(posedge clk or negedge Nrst)
+               if (!Nrst) begin
+                       insn_2a <= 32'h00000000;
+                       stall_1a <= 0;
+               end else begin
+                       insn_2a <= insn_1a;
+                       stall_1a <= stall_0a;
+               end
+       
+       always @(*)
+               if (stall_1a)
+                       insn_1a = insn_2a;

                else
                else

-                       nextpc = prevpc + 32'h4;
-       
-       assign rd_addr = pc;
-       assign rd_req = !stall;
-                       
-       always @(posedge clk)
-       begin
-               if (!rd_wait || !Nrst)
-                       prevpc <= nextpc;
-               if (!stall)
-               begin
-                       bubble <= rd_wait;
-                       insn <= rd_data;
-                       pc <= nextpc;
+                       insn_1a = ic__rd_data_1a;
+       
+       assign ic__rd_addr_0a = reqpc_0a;
+       assign ic__rd_req_0a = 1;
+       
+       always @(posedge clk or negedge Nrst)
+               if (!Nrst) begin
+                       bubble_1a <= 1;
+                       pc_1a <= 32'h00000000;
+               end else if (!stall_0a) begin
+                       bubble_1a <= (jmp_0a || qjmp || ic__rd_wait_0a);
+                       pc_1a <= reqpc_0a;
+               end
+       
+       always @(posedge clk or negedge Nrst)
+               if (!Nrst)
+                       reqpc_0a <= 0;
+               else if (!stall_0a && !ic__rd_wait_0a) begin
+                       if (qjmp)
+                               reqpc_0a <= qjmppc;
+                       else if (jmp_0a)
+                               reqpc_0a <= jmppc_0a;
+                       else
+                               reqpc_0a <= reqpc_0a + 4;

                end
                end

-       end

 endmodule
 endmodule