Update ID stage to support ZCMP, ZCMT and CVXIF with Superscalar (#2756)

Add support for Superscalar with ZCMP, ZCMT and CVXIF.
ZCMP decoder, ZCMT decoder and CVXIF interface driver are using port 0.
Standard RVC and 32 bits instruction can take port 0 or 1.

Author: Gchauvon

core/commit_stage.sv

@@ -301,10 +301,10 @@ module commit_stage
     end
 
     if (CVA6Cfg.NrCommitPorts > 1) begin
-
-      commit_ack_o[1] = 1'b0;
-      we_gpr_o[1]     = 1'b0;
-      wdata_o[1]      = commit_instr_i[1].result;
+      commit_macro_ack[1] = 1'b0;
+      commit_ack_o[1]     = 1'b0;
+      we_gpr_o[1]         = 1'b0;
+      wdata_o[1]          = commit_instr_i[1].result;
 
       // -----------------
       // Commit Port 2
@@ -350,10 +350,9 @@ module commit_stage
       end
     end
     if (CVA6Cfg.RVZCMP) begin
-      if (CVA6Cfg.NrCommitPorts > 1)
-        commit_macro_ack_o = (commit_instr_i[0].is_macro_instr || commit_instr_i[1].is_macro_instr) ? commit_macro_ack : commit_ack_o;
-      else
-        commit_macro_ack_o = (commit_instr_i[0].is_macro_instr) ? commit_macro_ack : commit_ack_o;
+      for (int i = 0; i < CVA6Cfg.NrCommitPorts; i++) begin
+        commit_macro_ack_o[i] = commit_instr_i[i].is_macro_instr ? commit_macro_ack[i] : commit_ack_o[i];
+      end
     end else commit_macro_ack_o = commit_ack_o;
   end
 

core/cvxif_compressed_if_driver.sv

@@ -16,24 +16,24 @@ module cvxif_compressed_if_driver #(
     input logic                    clk_i,
     // Asynchronous reset active low - SUBSYSTEM
     input logic                    rst_ni,
+    input logic                    flush_i,
     // CVA6 Hart id
     input logic [CVA6Cfg.XLEN-1:0] hart_id_i,
 
-    input logic [CVA6Cfg.NrIssuePorts-1:0]       is_compressed_i,
-    input logic [CVA6Cfg.NrIssuePorts-1:0]       is_illegal_i,
-    input logic [CVA6Cfg.NrIssuePorts-1:0]       instruction_valid_i,
-    input logic [CVA6Cfg.NrIssuePorts-1:0][31:0] instruction_i,
+    input logic        is_compressed_i,
+    input logic        is_illegal_i,
+    input logic [31:0] instruction_i,
 
-    output logic               [CVA6Cfg.NrIssuePorts-1:0]       is_compressed_o,
-    output logic               [CVA6Cfg.NrIssuePorts-1:0]       is_illegal_o,
-    output logic               [CVA6Cfg.NrIssuePorts-1:0][31:0] instruction_o,
-    input  logic                                                stall_i,
-    output logic               [CVA6Cfg.NrIssuePorts-1:0]       stall_o,
+    output logic                      is_compressed_o,
+    output logic                      is_illegal_o,
+    output logic               [31:0] instruction_o,
+    input  logic                      stall_i,
+    output logic                      stall_o,
     // CVXIF Compressed interface
-    input  logic                                                compressed_ready_i,
-    input  x_compressed_resp_t                                  compressed_resp_i,
-    output logic                                                compressed_valid_o,
-    output x_compressed_req_t                                   compressed_req_o
+    input  logic                      compressed_ready_i,
+    input  x_compressed_resp_t        compressed_resp_i,
+    output logic                      compressed_valid_o,
+    output x_compressed_req_t         compressed_req_o
 );
 
 
@@ -44,32 +44,22 @@ module cvxif_compressed_if_driver #(
     compressed_valid_o      = 1'b0;
     compressed_req_o.instr  = '0;
     compressed_req_o.hartid = hart_id_i;
-    stall_o[0]              = stall_i;
-    stall_o[1]              = 1'b0;
-    if (is_illegal_i[0]) begin
-      compressed_valid_o = is_illegal_i[0] && instruction_valid_i[0];
-      compressed_req_o.instr = instruction_i[0][15:0];
-      is_illegal_o[0] = ~compressed_resp_i.accept;
-      instruction_o[0] = compressed_resp_i.accept ? compressed_resp_i.instr : instruction_i[0];
-      is_compressed_o[0] = compressed_resp_i.accept ? 1'b0 : is_compressed_i[0];
+    stall_o                 = stall_i;
+    if (is_illegal_i) begin
+      compressed_valid_o = is_illegal_i;
+      compressed_req_o.instr = instruction_i[15:0];
+      is_illegal_o = ~compressed_resp_i.accept;
+      instruction_o = compressed_resp_i.accept ? compressed_resp_i.instr : instruction_i;
+      is_compressed_o = compressed_resp_i.accept ? 1'b0 : is_compressed_i;
       if (~stall_i) begin
         // Propagate stall from macro decoder or wait for compressed ready if compressed transaction is happening.
-        // Stall if both instruction are illegal
-        stall_o[0] = (compressed_valid_o && ~compressed_ready_i);
-        if (CVA6Cfg.SuperscalarEn) begin
-          stall_o[1] = is_illegal_i[1];
-        end
+        stall_o = (compressed_valid_o && ~compressed_ready_i);
       end
     end
-    if (CVA6Cfg.SuperscalarEn) begin
-      if (~is_illegal_i[0] && is_illegal_i[1]) begin  // 2nd instruction is illegal
-        compressed_valid_o = is_illegal_i[1] && instruction_valid_i[1];
-        compressed_req_o.instr = instruction_i[1][15:0];
-        is_illegal_o[1] = ~compressed_resp_i.accept;
-        instruction_o[1] = compressed_resp_i.accept ? compressed_resp_i.instr : instruction_i[1];
-        is_compressed_o[1] = compressed_resp_i.accept ? 1'b0 : is_compressed_i[1];
-        stall_o[1] = (compressed_valid_o && ~compressed_ready_i);
-      end
+    if (flush_i) begin
+      compressed_valid_o      = 1'b0;
+      compressed_req_o.instr  = '0;
+      compressed_req_o.hartid = hart_id_i;
     end
   end
 

core/cvxif_fu.sv

@@ -56,21 +56,18 @@ module cvxif_fu
 
   assign x_ready_o = 1'b1; // Readyness of cvxif_fu is determined in issue stage by CVXIF issue interface
   // Result signals
-  assign x_valid_o = x_illegal_i && x_valid_i ? 1'b1 : result_valid_i;
+  assign x_valid_o = x_illegal_i || result_valid_i;
   assign x_result_o = result_i.data;
   assign x_trans_id_o = x_illegal_i ? x_trans_id_i : result_i.id;
   assign x_we_o = result_i.we;
   assign x_rd_o = result_i.rd;
 
   // Handling of illegal instruction exception
   always_comb begin
-    x_exception_o = '0;  // No exception in this interface
-    if (x_illegal_i && x_valid_i) begin
-      x_exception_o.valid = '1;
-      x_exception_o.cause = riscv::ILLEGAL_INSTR;
-      if (CVA6Cfg.TvalEn)
-        x_exception_o.tval = x_off_instr_i;  // TODO Optimization : Set exception in IRO.
-    end
+    x_exception_o.valid = x_illegal_i;
+    x_exception_o.cause = x_illegal_i ? riscv::ILLEGAL_INSTR : '0;
+    if (CVA6Cfg.TvalEn)
+      x_exception_o.tval = x_off_instr_i;  // TODO Optimization : Set exception in IRO.
   end
 
 endmodule