IRO: always allow an ALU instruction to be executed

Signed-off-by: Alban Gruin <alban.gruin@irit.fr>

src/issue_read_operands.sv

@@ -128,9 +128,9 @@ module issue_read_operands import ariane_pkg::*; #(
     // this obviously depends on the functional unit we need
     always_comb begin : unit_busy
         unique case (issue_instr_i.fu)
-            NONE:
+            NONE, ALU, CTRL_FLOW:
                 fu_busy = 1'b0;
-            ALU, CTRL_FLOW, CSR, MULT:
+            CSR, MULT:
                 fu_busy = ~flu_ready_i;
             FPU, FPU_VEC:
                 fu_busy = ~fpu_ready_i;
@@ -336,11 +336,6 @@ module issue_read_operands import ariane_pkg::*; #(
                 issue_ack_o = 1'b1;
             end
         end
-        // after a multiplication was issued we can only issue another multiplication
-        // otherwise we will get contentions on the fixed latency bus
-        if (mult_valid_q && issue_instr_i.fu != MULT) begin
-            issue_ack_o = 1'b0;
-        end
     end
 
     // ----------------------