Various debug related improvements

Implemented c.ebreak instruction
Debugging with rvc seems to work properly now

compressed_decoder.sv

@@ -58,7 +58,12 @@ module compressed_decoder
               // c.add -> add rd, rd, rs2
               instr_o = {7'b0, instr_i[6:2], instr_i[11:7], 3'b000, instr_i[11:7], `OPCODE_OP};
             end
-            if (instr_i[11:7] == 5'b0)  illegal_instr_o = 1'b1;
+            if (instr_i[11:7] == 5'b0) begin
+              if (instr_i[6:2] == 5'b0)
+                instr_o = {32'h00_10_00_73}; // EBREAK
+              else
+                illegal_instr_o = 1'b1;
+            end
           end
 
           3'b001: begin

controller.sv

@@ -1032,7 +1032,7 @@ module controller
 
         // handle conditional branches
         if (jump_in_id == `BRANCH_COND) begin
-          // handle branch if decision is availble in next cycle
+          // handle branch if decision is available in next cycle
           if (~stall_id_o)
             ctrl_fsm_ns = BRANCH;
         end
@@ -1083,13 +1083,17 @@ module controller
         end
 
         // take care of debug
-        // branches take two cycles, jumps just one
-        // everything else can be done immediately
-        if(trap_hit_i == 1'b1 && stall_ex_o == 1'b0 && jump_in_id == `BRANCH_NONE)
+        // branch conditional will be handled in next state
+        if(trap_hit_i && jump_in_id != `BRANCH_COND)
         begin
+          // halt pipeline immediately
           halt_if = 1'b1;
           halt_id = 1'b1;
-          ctrl_fsm_ns = DBG_FLUSH_EX;
+
+          // make sure the current instruction has been executed
+          // before changing state to non-decode
+          if (~stall_ex_o)
+            ctrl_fsm_ns = DBG_FLUSH_EX;
         end
       end
 
@@ -1130,6 +1134,7 @@ module controller
         end
       end
 
+      // make sure EX stage is flushed
       DBG_FLUSH_EX:
       begin
         halt_if = 1'b1;
@@ -1139,6 +1144,7 @@ module controller
           ctrl_fsm_ns = DBG_FLUSH_WB;
       end
 
+      // make sure WB stage is flushed
       DBG_FLUSH_WB:
       begin
         halt_if = 1'b1;
@@ -1148,15 +1154,19 @@ module controller
           ctrl_fsm_ns = DBG_SIGNAL;
       end
 
+      // now we can signal to the debugger that our pipeline is empty and it
+      // can examine our current state
       DBG_SIGNAL:
       begin
         dbg_trap_o = 1'b1;
-        halt_if = 1'b1;
-        halt_id = 1'b1;
+        halt_if    = 1'b1;
+        halt_id    = 1'b1;
 
         ctrl_fsm_ns = DBG_WAIT;
       end
 
+      // The Debugger is active in this state
+      // we wait until it is done and go back to DECODE
       DBG_WAIT:
       begin
         halt_if = 1'b1;
@@ -1170,9 +1180,8 @@ module controller
         end
 
         if(dbg_stall_i == 1'b0) begin
-          halt_if = 1'b0;
-          halt_id = 1'b0;
-
+          halt_if     = 1'b0;
+          halt_id     = 1'b0;
           ctrl_fsm_ns = DECODE;
         end
       end

id_stage.sv

@@ -143,7 +143,6 @@ module id_stage
     input  logic [31:0] regfile_alu_wdata_fw_i,
 
     // Performance Counters
-    output logic        perf_compressed_o,    // current instrution is compressed
     output logic        perf_jump_o,          // we are executing a jump instruction
     output logic        perf_branch_o,        // we are executing a branch instruction
     output logic        perf_jr_stall_o,      // jump-register-hazard
@@ -509,7 +508,7 @@ module id_stage
     .we_b_i       ( (dbg_reg_mux_i == 1'b0) ? regfile_alu_we_fw_i    : dbg_reg_we_i    )
   );
 
-  assign dbg_reg_rdata_o = regfile_data_ra_id;
+  assign dbg_reg_rdata_o = regfile_data_rc_id;
 
   ////////////////////////////////////////////////////////////////////
   //    ____ ___  _   _ _____ ____   ___  _     _     _____ ____    //

riscv_core.sv

@@ -664,7 +664,7 @@ module riscv_core
     rs2_value  = id_stage_i.operand_b_fw_id;
 
     // special case for WFI because we don't wait for unstalling there
-    if ((id_stage_i.stall_id_o == 1'b0 && id_stage_i.controller_i.ctrl_fsm_cs == id_stage_i.controller_i.DECODE) || id_stage_i.controller_i.pipe_flush)
+    if ((id_stage_i.stall_ex_o == 1'b0 && is_decoding) || id_stage_i.controller_i.pipe_flush)
     begin
       mnemonic = "";
       imm = 0;