Adds PipelineSwitch entity and testbench

Introduces the PipelineSwitch component with configurable routing behavior based on input comparison modes. Implements modes such as "none", "or", "and", "xor", "equal", and others. Adds a comprehensive testbench to validate functionality across all supported modes.

src/PipelineSwitch.vhd

@@ -0,0 +1,192 @@
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+use ieee.math_real.all;
+
+entity PipelineSwitch is
+    generic (
+        --@ Width of the comparison input and mask.
+        --@ This defines the bit width of `I_Match` and `G_Mask`.
+        G_MaskWidth : integer          := 4;
+
+        --@ Comparison mask or reference value used to control routing.
+        --@ Its width must match `G_MaskWidth`.
+        G_Mask      : std_logic_vector := "1010";
+
+        --@ Comparison mode that determines to which output the data is routed.
+        --@ Available modes:
+        --@ - `"none"`:        Always route to `Default`.
+        --@ - `"or"`:          Route to `Selected` if **any** bit in `I_Match` matches a set bit in `G_Mask`.
+        --@ - `"and"`:         Route to `Selected` if **all** bits set in `G_Mask` are also set in `I_Match`.
+        --@ - `"xor"`:         Route to `Selected` if **any** bit differs between `I_Match` and `G_Mask`.
+        --@ - `"equal"`:       Route to `Selected` if `I_Match` is **bitwise equal** to `G_Mask`.
+        --@ - `"not_equal"`:   Route to `Selected` if `I_Match` is **not equal** to `G_Mask`.
+        --@ - `"gt"`:          Route to `Selected` if `I_Match` **>** `G_Mask` (unsigned).
+        --@ - `"ge"`:          Route to `Selected` if `I_Match` **≥** `G_Mask`.
+        --@ - `"lt"`:          Route to `Selected` if `I_Match` **<** `G_Mask`.
+        --@ - `"le"`:          Route to `Selected` if `I_Match` **≤** `G_Mask`.
+        G_MaskMode  : string           := "equal"
+    );
+
+    port (
+        --@ Input value to be compared against `G_Mask` to determine routing.
+        I_Match          : in  std_logic_vector(G_MaskWidth - 1 downto 0) := (others => '0');
+
+        --@ @virtualbus AXI-Flags-In @dir In Input interface for AXI-like handshake
+        --@ AXI-like valid; (**Synchronous**, **Active high**)
+        I_Valid          : in  std_logic                                  := '0';
+        --@ AXI-like ready; (**Synchronous**, **Active high**)
+        O_Ready          : out std_logic                                  := '0';
+        --@ @end
+
+        --@ @virtualbus AXI-Flags-Out @dir Out Output interface for unmatched routing
+        --@ Activated when the comparison **fails**.
+        --@ AXI-like valid; (**Synchronous**, **Active high**)
+        O_Default_Valid  : out std_logic                                  := '0';
+        --@ AXI-like ready; (**Synchronous**, **Active high**)
+        I_Default_Ready  : in  std_logic                                  := '0';
+        --@ @end
+
+        --@ @virtualbus AXI-Flags-Out @dir Out Output interface for matched routing
+        --@ Activated when the comparison **succeeds**.
+        --@ AXI-like valid; (**Synchronous**, **Active high**)
+        O_Selected_Valid : out std_logic                                  := '0';
+        --@ AXI-like ready; (**Synchronous**, **Active high**)
+        I_Selected_Ready : in  std_logic                                  := '0'
+        --@ @end
+    );
+
+end entity PipelineSwitch;
+
+architecture RTL of PipelineSwitch is
+    function strings_equal(A, B : string) return boolean is
+    begin
+        if A'length /= B'length then
+            return false;
+        end if;
+
+        for i in A'range loop
+            if A(i) /= B(i) then
+                return false;
+            end if;
+        end loop;
+
+        return true;
+    end function;
+
+    constant K_Mode_None           : string    := "none";
+    constant K_Mode_OR             : string    := "or";
+    constant K_Mode_XOR            : string    := "xor";
+    constant K_Mode_AND            : string    := "and";
+    constant K_Mode_Equal          : string    := "equal";
+    constant K_Mode_NotEqual       : string    := "not_equal";
+    constant K_Mode_GT             : string    := "gt";
+    constant K_Mode_GE             : string    := "ge";
+    constant K_Mode_LT             : string    := "lt";
+    constant K_Mode_LE             : string    := "le";
+
+    signal C_ShouldRouteToSelected : std_logic := '0';
+begin
+    assert G_Mask'length = G_MaskWidth
+    report "G_Mask length does not match G_MaskWidth" severity failure;
+
+    process (I_Match)
+    begin
+        if strings_equal(G_MaskMode, K_Mode_None) then
+            --@ No condition: Always route to Default
+            C_ShouldRouteToSelected <= '0';
+
+        elsif strings_equal(G_MaskMode, K_Mode_OR) then
+            --@ Route to Selected if any bit in I_Match is also set in G_Mask
+            if (I_Match and G_Mask) /= (G_MaskWidth - 1 downto 0 => '0') then
+                C_ShouldRouteToSelected <= '1';
+            else
+                C_ShouldRouteToSelected <= '0';
+            end if;
+
+        elsif strings_equal(G_MaskMode, K_Mode_XOR) then
+            --@ Route to Selected if any bit differs between I_Match and G_Mask
+            if (I_Match xor G_Mask) /= (G_MaskWidth - 1 downto 0 => '0') then
+                C_ShouldRouteToSelected <= '1';
+            else
+                C_ShouldRouteToSelected <= '0';
+            end if;
+
+        elsif strings_equal(G_MaskMode, K_Mode_AND) then
+            --@ Route to Selected if all bits set in G_Mask are also set in I_Match
+            if (I_Match and G_Mask) = G_Mask then
+                C_ShouldRouteToSelected <= '1';
+            else
+                C_ShouldRouteToSelected <= '0';
+            end if;
+
+        elsif strings_equal(G_MaskMode, K_Mode_Equal) then
+            --@ Route to Selected if I_Match is exactly equal to G_Mask
+            if I_Match = G_Mask then
+                C_ShouldRouteToSelected <= '1';
+            else
+                C_ShouldRouteToSelected <= '0';
+            end if;
+
+        elsif strings_equal(G_MaskMode, K_Mode_NotEqual) then
+            --@ Route to Selected if I_Match is not equal to G_Mask
+            if I_Match /= G_Mask then
+                C_ShouldRouteToSelected <= '1';
+            else
+                C_ShouldRouteToSelected <= '0';
+            end if;
+
+        elsif strings_equal(G_MaskMode, K_Mode_GT) then
+            --@ Route to Selected if I_Match > G_Mask (interpreted as unsigned)
+            if unsigned(I_Match) > unsigned(G_Mask) then
+                C_ShouldRouteToSelected <= '1';
+            else
+                C_ShouldRouteToSelected <= '0';
+            end if;
+
+        elsif strings_equal(G_MaskMode, K_Mode_GE) then
+            --@ Route to Selected if I_Match >= G_Mask (unsigned)
+            if unsigned(I_Match) >= unsigned(G_Mask) then
+                C_ShouldRouteToSelected <= '1';
+            else
+                C_ShouldRouteToSelected <= '0';
+            end if;
+
+        elsif strings_equal(G_MaskMode, K_Mode_LT) then
+            --@ Route to Selected if I_Match < G_Mask (unsigned)
+            if unsigned(I_Match) < unsigned(G_Mask) then
+                C_ShouldRouteToSelected <= '1';
+            else
+                C_ShouldRouteToSelected <= '0';
+            end if;
+
+        elsif strings_equal(G_MaskMode, K_Mode_LE) then
+            --@ Route to Selected if I_Match <= G_Mask (unsigned)
+            if unsigned(I_Match)    <= unsigned(G_Mask) then
+                C_ShouldRouteToSelected <= '1';
+            else
+                C_ShouldRouteToSelected <= '0';
+            end if;
+
+        else
+            --@ Unknown comparison mode: fallback to Default
+            C_ShouldRouteToSelected <= '0';
+        end if;
+    end process;
+
+    process (I_Valid, I_Default_Ready, I_Selected_Ready, C_ShouldRouteToSelected)
+    begin
+        if C_ShouldRouteToSelected = '1' then
+            -- Route to Selected
+            O_Selected_Valid <= I_Valid;
+            O_Default_Valid  <= '0';
+            O_Ready          <= I_Selected_Ready;
+        else
+            -- Route to Default
+            O_Selected_Valid <= '0';
+            O_Default_Valid  <= I_Valid;
+            O_Ready          <= I_Default_Ready;
+        end if;
+    end process;
+
+end architecture;