Altera opt 3

core/ariane_regfile_fpga.sv

@@ -1,4 +1,5 @@
 // Copyright 2018 ETH Zurich and University of Bologna.
+// Copyright 2024 - PlanV Technologies for additionnal contribution.
 // Copyright and related rights are licensed under the Solderpad Hardware
 // License, Version 0.51 (the "License"); you may not use this file except in
 // compliance with the License.  You may obtain a copy of the License at
@@ -15,7 +16,7 @@
 //                 Noam Gallmann - [email protected]
 //                 Felipe Lisboa Malaquias
 //                 Henry Suzukawa
-//
+//                 Angela Gonzalez - PlanV Technologies
 //
 // Description:    This register file is optimized for implementation on
 //                 FPGAs. The register file features one distributed RAM block per implemented
@@ -50,11 +51,16 @@ module ariane_regfile_fpga #(
   localparam LOG_NR_WRITE_PORTS = CVA6Cfg.NrCommitPorts == 1 ? 1 : $clog2(CVA6Cfg.NrCommitPorts);
 
   // Distributed RAM usually supports one write port per block - duplicate for each write port.
-  logic [            NUM_WORDS-1:0][        DATA_WIDTH-1:0] mem             [CVA6Cfg.NrCommitPorts];
+  logic [NUM_WORDS-1:0][DATA_WIDTH-1:0] mem[CVA6Cfg.NrCommitPorts];
+
+  logic [CVA6Cfg.NrCommitPorts-1:0][NUM_WORDS-1:0] we_dec;
+  logic [NUM_WORDS-1:0][LOG_NR_WRITE_PORTS-1:0] mem_block_sel;
+  logic [NUM_WORDS-1:0][LOG_NR_WRITE_PORTS-1:0] mem_block_sel_q;
+  logic [CVA6Cfg.NrCommitPorts-1:0][DATA_WIDTH-1:0] wdata_reg;
+  logic [NR_READ_PORTS-1:0] read_after_write;
 
-  logic [CVA6Cfg.NrCommitPorts-1:0][         NUM_WORDS-1:0] we_dec;
-  logic [            NUM_WORDS-1:0][LOG_NR_WRITE_PORTS-1:0] mem_block_sel;
-  logic [            NUM_WORDS-1:0][LOG_NR_WRITE_PORTS-1:0] mem_block_sel_q;
+  logic [NR_READ_PORTS-1:0][4:0] raddr_q;
+  logic [NR_READ_PORTS-1:0][4:0] raddr;
 
   // write adress decoder (for block selector)
   always_comb begin
@@ -88,36 +94,55 @@ module ariane_regfile_fpga #(
   always_ff @(posedge clk_i or negedge rst_ni) begin
     if (!rst_ni) begin
       mem_block_sel_q <= '0;
+      raddr_q <= '0;
     end else begin
       mem_block_sel_q <= mem_block_sel;
+      if (CVA6Cfg.FpgaAlteraEn) raddr_q <= raddr_i;
+      else raddr_q <= '0;
     end
   end
 
   // distributed RAM blocks
   logic [NR_READ_PORTS-1:0][DATA_WIDTH-1:0] mem_read[CVA6Cfg.NrCommitPorts];
+  logic [NR_READ_PORTS-1:0][DATA_WIDTH-1:0] mem_read_sync[CVA6Cfg.NrCommitPorts];
   for (genvar j = 0; j < CVA6Cfg.NrCommitPorts; j++) begin : regfile_ram_block
     always_ff @(posedge clk_i) begin
       if (we_i[j] && ~waddr_i[j] != 0) begin
         mem[j][waddr_i[j]] <= wdata_i[j];
+        if (CVA6Cfg.FpgaAlteraEn)
+          wdata_reg[j] <= wdata_i[j];  // register data written in case is needed to read next cycle
+        else wdata_reg[j] <= '0;
+      end
+      if (CVA6Cfg.FpgaAlteraEn) begin
+        for (int k = 0; k < NR_READ_PORTS; k++) begin : block_read
+          mem_read_sync[j][k] = mem[j][raddr_i[k]];  // synchronous RAM
+          read_after_write[k] <= '0;
+          if (waddr_i[j] == raddr_i[k])
+            read_after_write[k] <= we_i[j] && ~waddr_i[j] != 0; // Identify if we need to read the content that was written
+        end
       end
     end
     for (genvar k = 0; k < NR_READ_PORTS; k++) begin : block_read
-      assign mem_read[j][k] = mem[j][raddr_i[k]];
+      assign mem_read[j][k] = CVA6Cfg.FpgaAlteraEn ? ( read_after_write[k] ? wdata_reg[j]: mem_read_sync[j][k]) : mem[j][raddr_i[k]];
     end
   end
+  //with synchronous ram there is the need to adjust which address is used at the output MUX
+  assign raddr = CVA6Cfg.FpgaAlteraEn ? raddr_q : raddr_i;
 
   // output MUX
   logic [NR_READ_PORTS-1:0][LOG_NR_WRITE_PORTS-1:0] block_addr;
   for (genvar k = 0; k < NR_READ_PORTS; k++) begin : regfile_read_port
-    assign block_addr[k] = mem_block_sel_q[raddr_i[k]];
-    assign rdata_o[k] = (ZERO_REG_ZERO && raddr_i[k] == '0) ? '0 : mem_read[block_addr[k]][k];
+    assign block_addr[k] = mem_block_sel_q[raddr[k]];
+    assign rdata_o[k] = (ZERO_REG_ZERO && raddr[k] == '0) ? '0 : mem_read[block_addr[k]][k];
   end
 
   // random initialization of the memory to suppress assert warnings on Questa.
   initial begin
     for (int i = 0; i < CVA6Cfg.NrCommitPorts; i++) begin
       for (int j = 0; j < NUM_WORDS; j++) begin
-        mem[i][j] = $random();
+        if (!CVA6Cfg.FpgaAlteraEn)
+          mem[i][j] = $random();  //quartus does not support this random statement on synthesis
+        else mem[i][j] = '0;
       end
     end
   end

core/cva6.sv

@@ -401,7 +401,7 @@ module cva6
   // --------------
   // ID <-> ISSUE
   // --------------
-  scoreboard_entry_t [CVA6Cfg.NrIssuePorts-1:0] issue_entry_id_issue;
+  scoreboard_entry_t [CVA6Cfg.NrIssuePorts-1:0] issue_entry_id_issue, issue_entry_id_issue_prev;
   logic [CVA6Cfg.NrIssuePorts-1:0][31:0] orig_instr_id_issue;
   logic [CVA6Cfg.NrIssuePorts-1:0] issue_entry_valid_id_issue;
   logic [CVA6Cfg.NrIssuePorts-1:0] is_ctrl_fow_id_issue;
@@ -690,6 +690,7 @@ module cva6
       .fetch_entry_ready_o(fetch_ready_id_if),
 
       .issue_entry_o      (issue_entry_id_issue),
+      .issue_entry_o_prev (issue_entry_id_issue_prev),
       .orig_instr_o       (orig_instr_id_issue),
       .issue_entry_valid_o(issue_entry_valid_id_issue),
       .is_ctrl_flow_o     (is_ctrl_fow_id_issue),
@@ -806,6 +807,7 @@ module cva6
       .stall_i                 (stall_acc_id),
       // ID Stage
       .decoded_instr_i         (issue_entry_id_issue),
+      .decoded_instr_i_prev    (issue_entry_id_issue_prev),
       .orig_instr_i            (orig_instr_id_issue),
       .decoded_instr_valid_i   (issue_entry_valid_id_issue),
       .is_ctrl_flow_i          (is_ctrl_fow_id_issue),

core/id_stage.sv

@@ -41,6 +41,7 @@ module id_stage #(
     output logic [CVA6Cfg.NrIssuePorts-1:0] fetch_entry_ready_o,
     // Handshake's data between decode and issue - ISSUE
     output scoreboard_entry_t [CVA6Cfg.NrIssuePorts-1:0] issue_entry_o,
+    output scoreboard_entry_t [CVA6Cfg.NrIssuePorts-1:0] issue_entry_o_prev,
     // Instruction value - ISSUE
     output logic [CVA6Cfg.NrIssuePorts-1:0][31:0] orig_instr_o,
     // Handshake's valid between decode and issue - ISSUE
@@ -266,6 +267,7 @@ module id_stage #(
   // ------------------
   for (genvar i = 0; i < CVA6Cfg.NrIssuePorts; i++) begin
     assign issue_entry_o[i] = issue_q[i].sbe;
+    assign issue_entry_o_prev[i] = CVA6Cfg.FpgaAlteraEn ? issue_n[i].sbe : '0;
     assign issue_entry_valid_o[i] = issue_q[i].valid;
     assign is_ctrl_flow_o[i] = issue_q[i].is_ctrl_flow;
     assign orig_instr_o[i] = issue_q[i].orig_instr;

core/issue_read_operands.sv

@@ -39,6 +39,7 @@ module issue_read_operands
     input logic stall_i,
     // Entry about the instruction to issue - SCOREBOARD
     input scoreboard_entry_t [CVA6Cfg.NrIssuePorts-1:0] issue_instr_i,
+    input scoreboard_entry_t [CVA6Cfg.NrIssuePorts-1:0] issue_instr_i_prev,
     // Instruction to issue - SCOREBOARD
     input logic [CVA6Cfg.NrIssuePorts-1:0][31:0] orig_instr_i,
     // Is there an instruction to issue - SCOREBOARD
@@ -954,11 +955,12 @@ module issue_read_operands
   logic [CVA6Cfg.NrCommitPorts-1:0][CVA6Cfg.XLEN-1:0] wdata_pack;
   logic [CVA6Cfg.NrCommitPorts-1:0]                   we_pack;
 
-  for (genvar i = 0; i < CVA6Cfg.NrIssuePorts; i++) begin
-    assign raddr_pack[i*OPERANDS_PER_INSTR+0] = issue_instr_i[i].rs1;
-    assign raddr_pack[i*OPERANDS_PER_INSTR+1] = issue_instr_i[i].rs2;
+  //adjust address to read from register file (when synchronous RAM is used reads take one cycle, so we advance the address)   
+  for (genvar i = 0; i <= CVA6Cfg.NrIssuePorts - 1; i++) begin
+    assign raddr_pack[i*OPERANDS_PER_INSTR+0] = CVA6Cfg.FpgaEn && CVA6Cfg.FpgaAlteraEn ? issue_instr_i_prev[i].rs1[4:0] : issue_instr_i[i].rs1[4:0];
+    assign raddr_pack[i*OPERANDS_PER_INSTR+1] = CVA6Cfg.FpgaEn && CVA6Cfg.FpgaAlteraEn ? issue_instr_i_prev[i].rs2[4:0] : issue_instr_i[i].rs2[4:0];
     if (OPERANDS_PER_INSTR == 3) begin
-      assign raddr_pack[i*OPERANDS_PER_INSTR+2] = issue_instr_i[i].result[4:0];
+      assign raddr_pack[i*OPERANDS_PER_INSTR+2] = CVA6Cfg.FpgaEn && CVA6Cfg.FpgaAlteraEn ? issue_instr_i_prev[i].result[4:0] : issue_instr_i[i].result[4:0];
     end
   end
 

core/issue_stage.sv

@@ -43,6 +43,7 @@ module issue_stage
     input logic stall_i,
     // Handshake's data with decode stage - ID_STAGE
     input scoreboard_entry_t [CVA6Cfg.NrIssuePorts-1:0] decoded_instr_i,
+    input scoreboard_entry_t [CVA6Cfg.NrIssuePorts-1:0] decoded_instr_i_prev,
     // instruction value - ID_STAGE
     input logic [CVA6Cfg.NrIssuePorts-1:0][31:0] orig_instr_i,
     // Handshake's valid with decode stage - ID_STAGE
@@ -253,6 +254,7 @@ module issue_stage
       .flush_i                 (flush_unissued_instr_i),
       .stall_i,
       .issue_instr_i           (issue_instr_sb_iro),
+      .issue_instr_i_prev      (decoded_instr_i_prev),
       .orig_instr_i            (orig_instr_sb_iro),
       .issue_instr_valid_i     (issue_instr_valid_sb_iro),
       .issue_ack_o             (issue_ack_iro_sb),