Analogizer (Feature Request): add support for SNAC PSX two game controllers (digital and analog) for the Pocket Analogizer adapter

[RndMnkIII]

Recently I've updated Pocket Analogizer SNAC support to extend it to use two PSX game controllers (digital and analog types).
This repo hold the most recent Analogizer framework code:
https://github.com/RndMnkIII/Analogizer

This repo can be used as example of implementation and usage:
https://github.com/RndMnkIII/Analogizer_openfpga-pcengine

The following type of game controllers are supported:

• Digital controller (SCPH-1010)
• Analog Joystick (SCPH-1110)
• Dual Analog (SCPH-1180)
• DualShock 1 (SCPH-1200)
• DualShock 2 (SCPH-10010)

The relevant files are:

• openFPGA_Pocket_Analogizer_SNAC.sv
• analogizer_psx.sv
• dualshock_controller.v

Example of menu options for interact.json core configuration file:

 {
                "name": "SNAC Adapter",
                "id": 16,
                "type": "list",
                "enabled": true,
                "persist": true,
                "address": "0xF7000000",
                "defaultval": "0x00",
                "mask": "0xFFFFFFE0",
                "options": [
                  {
                  "value": "0x00",
                  "name": "None"
                  },
                  {
                  "value": "0x01",
                  "name": "DB15 Normal"
                  },
                  {
                  "value": "0x02",
                  "name": "NES"
                  },
                  {
                  "value": "0x03",
                  "name": "SNES"
                  },
                  {
                  "value": "0x04",
                  "name": "PCE 2BTN"
                  },
                  {
                  "value": "0x05",
                  "name": "PCE 6BTN"
                  },
                  {
                  "value": "0x06",
                  "name": "PCE Multitap"
                  },
                  {
                    "value": "0x09",
                    "name": "DB15 Fast"
                  },
                  {
                    "value": "0x0B",
                    "name": "SNES A,B<->X,Y"
                  },
                  {
                    "value": "0x11",
                    "name": "PSX (Digital DPAD)"
                  },
                  {
                    "value": "0x13",
                    "name": "PSX (Analog DPAD)"
                  }
                ]
            }

Example of mapping analog sticks to dpad, from Analogizer PC Engine core_top.v:

//*** Analogizer Interface V1.1 ***
reg analogizer_ena;
reg [3:0] analogizer_video_type;
reg [4:0] snac_game_cont_type /* synthesis keep */;
reg [3:0] snac_cont_assignment /* synthesis keep */;
  
wire [31:0] p1_joy, p2_joy; //analog sticks data, from Analogizer adapter module
//use PSX Dual Shock style left analog stick as directional pad
wire is_analog_input = (snac_game_cont_type == 5'h13);

//! Player 1 ---------------------------------------------------------------------------
reg p1_up, p1_down, p1_left, p1_right;
wire p1_up_analog, p1_down_analog, p1_left_analog, p1_right_analog;
//using left analog joypad
assign p1_up_analog    = (p1_joy[15:8] < 8'h40) ? 1'b1 : 1'b0; //analog range UP 0x00 Idle 0x80 DOWN 0xFF, DEADZONE +- 0x15
assign p1_down_analog  = (p1_joy[15:8] > 8'hC0) ? 1'b1 : 1'b0; 
assign p1_left_analog  = (p1_joy[7:0]  < 8'h40) ? 1'b1 : 1'b0; //analog range LEFT 0x00 Idle 0x80 RIGHT 0xFF, DEADZONE +- 0x15
assign p1_right_analog = (p1_joy[7:0]  > 8'hC0) ? 1'b1 : 1'b0;

always @(posedge clk_sys_42_95) begin
    p1_up    <= (is_analog_input) ? p1_up_analog    : p1_btn[0];
    p1_down  <= (is_analog_input) ? p1_down_analog  : p1_btn[1];
    p1_left  <= (is_analog_input) ? p1_left_analog  : p1_btn[2];
    p1_right <= (is_analog_input) ? p1_right_analog : p1_btn[3];
end
//! Player 2 ---------------------------------------------------------------------------
reg p2_up, p2_down, p2_left, p2_right;
wire p2_up_analog, p2_down_analog, p2_left_analog, p2_right_analog;
//using left analog joypad
assign p2_up_analog    = (p2_joy[15:8] < 8'h40) ? 1'b1 : 1'b0; //analog range UP 0x00 Idle 0x80 DOWN 0xFF, DEADZONE +- 0x15
assign p2_down_analog  = (p2_joy[15:8] > 8'hC0) ? 1'b1 : 1'b0; 
assign p2_left_analog  = (p2_joy[7:0]  < 8'h40) ? 1'b1 : 1'b0; //analog range LEFT 0x00 Idle 0x80 RIGHT 0xFF, DEADZONE +- 0x15
assign p2_right_analog = (p2_joy[7:0]  > 8'hC0) ? 1'b1 : 1'b0;

always @(posedge clk_sys_42_95) begin
    p2_up    <= (is_analog_input) ? p2_up_analog    : p2_btn[0];
    p2_down  <= (is_analog_input) ? p2_down_analog  : p2_btn[1];
    p2_left  <= (is_analog_input) ? p2_left_analog  : p2_btn[2];
    p2_right <= (is_analog_input) ? p2_right_analog : p2_btn[3];
end

  //switch between Analogizer SNAC and Pocket Controls for P1-P4 (P3,P4 when uses PCEngine Multitap)
  wire [15:0] p1_btn, p2_btn, p3_btn, p4_btn;
  reg [15:0] p1_controls, p2_controls, p3_controls, p4_controls; //to the system core game inputs (replaces Pocket framework inputs)

  always @(posedge clk_sys_42_95) begin
    if(snac_game_cont_type == 5'h0) begin //SNAC is disabled
                  p1_controls <= cont1_key_s;
                  p2_controls <= cont2_key_s;
                  p3_controls <= cont3_key_s;
                  p4_controls <= cont4_key_s;
    end
    else begin
      case(snac_cont_assignment)
      4'h0:    begin 
                  p1_controls <= {p1_btn[15:4],p1_right,p1_left,p1_down,p1_up};
                  p2_controls <= cont2_key_s;
                  p3_controls <= cont3_key_s;
                  p4_controls <= cont4_key_s;
                end
      4'h1:    begin 
                  p1_controls <= cont1_key_s;
                  p2_controls <= {p1_btn[15:4],p1_right,p1_left,p1_down,p1_up};
                  p3_controls <= cont3_key_s;
                  p4_controls <= cont4_key_s;
                end
      4'h2:    begin
                  p1_controls <= {p1_btn[15:4],p1_right,p1_left,p1_down,p1_up};
                  p2_controls <= {p2_btn[15:4],p2_right,p2_left,p2_down,p2_up};
                  p3_controls <= cont3_key_s;
                  p4_controls <= cont4_key_s;
                end
      4'h3:    begin
                  p1_controls <= {p2_btn[15:4],p2_right,p2_left,p2_down,p2_up};
                  p2_controls <= {p1_btn[15:4],p1_right,p1_left,p1_down,p1_up};
                  p3_controls <= cont3_key_s;
                  p4_controls <= cont4_key_s;
                end
      4'h4:    begin
                  p1_controls <= {p1_btn[15:4],p1_right,p1_left,p1_down,p1_up};
                  p2_controls <= {p2_btn[15:4],p2_right,p2_left,p2_down,p2_up};
                  p3_controls <= p3_btn;
                  p4_controls <= p4_btn;
                end
      4'h5:    begin
                  p1_controls <= p4_btn;
                  p2_controls <= p3_btn;
                  p3_controls <= {p2_btn[15:4],p2_right,p2_left,p2_down,p2_up};
                  p4_controls <= {p1_btn[15:4],p1_right,p1_left,p1_down,p1_up};
                end
      4'h6:    begin
                  p1_controls <= cont1_key_s;
                  p2_controls <= cont2_key_s;
                  p3_controls <= {p1_btn[15:4],p1_right,p1_left,p1_down,p1_up};
                  p4_controls <= {p2_btn[15:4],p2_right,p2_left,p2_down,p2_up};
                end
      default: begin
                  p1_controls <= cont1_key_s;
                  p2_controls <= cont2_key_s;
                  p3_controls <= cont3_key_s;
                  p4_controls <= cont4_key_s;
                end
      endcase
    end
  end