1 files changed, 146 insertions, 0 deletions
diff --git a/src/ada_chip.adb b/src/ada_chip.adb
new file mode 100644
index 0000000..b79db1c
--- /dev/null
+++ b/src/ada_chip.adb
@@ -0,0 +1,146 @@
+with Ada.Command_Line;
+with Ada.Numerics.Discrete_Random;
+with Ada.Text_IO;
+with Sf;
+
+with ISA; use ISA;
+with CPU;
+with Video;
+
+procedure Ada_Chip is
+   package Random_Byte is new Ada.Numerics.Discrete_Random (Byte);
+
+   Steps_Per_Frame : constant := 16;
+
+   State            : CPU.Instance;
+   Random_Generator : Random_Byte.Generator;
+
+   procedure Draw_Sprite (VX, VY : Register_Index; N : Byte) is
+      use Sf;
+
+      X, Y       : sfUint32;
+      Row        : aliased Byte;
+      Row_Pixels : Pixel with Address => Row'Address;
+      VF         : Boolean := False;
+   begin
+      X := sfUint32 (State.Registers (VX));
+      Y := sfUint32 (State.Registers (VY));
+
+      for I in 0 .. N - 1 loop
+         Row := State.Memory (State.Address_Register + Address (I));
+
+         for J in 0 .. 7 loop
+            if Row_Pixels (7 - J) then
+               if Video.Toggle_Pixel (X + sfUint32 (J), Y + sfUint32 (I)) then
+                  VF := True;
+               end if;
+            end if;
+         end loop;
+      end loop;
+
+      State.Registers (15) := (if VF then 1 else 0);
+   end Draw_Sprite;
+
+   procedure Run_Step is
+      ins : Opcode;
+   begin
+      ins := CPU.Get_Opcode (State);
+      case ins.Class is
+         when Flow =>
+            case ins.Value is
+               when 16#E0# => Video.Clear_Screen;
+               when 16#EE# => CPU.Ret (State);
+               when others => begin
+                  Ada.Text_IO.Put_Line ("Unknown flow instruction!");
+                  Ada.Text_IO.Put_Line (Opcode_Value'Image (ins.Value));
+                  delay 1.0;
+                  Video.Finish;
+               end;
+            end case;
+         when Jump => CPU.Jump (State, Address (ins.Value));
+         when Call => CPU.Call (State, Address (ins.Value));
+         when Equal =>
+            if State.Registers (X_Register (ins)) = To_Byte (ins) then
+               CPU.Skip (State);
+            end if;
+         when Not_Equal =>
+            if State.Registers (X_Register (ins)) /= To_Byte (ins) then
+               CPU.Skip (State);
+            end if;
+         when Compare =>
+            if State.Registers (X_Register (ins)) =
+               State.Registers (Y_Register (ins))
+            then
+               CPU.Skip (State);
+            end if;
+         when Set_Register =>
+            State.Registers (X_Register (ins)) := To_Byte (ins);
+         when Add =>
+            State.Registers (X_Register (ins)) :=
+               State.Registers (X_Register (ins)) + To_Byte (ins);
+         when Math =>
+            CPU.Math (State, X_Register (ins), Y_Register (ins),
+               To_Byte (ins) mod 16);
+         when Not_Compare =>
+            if State.Registers (X_Register (ins)) /=
+               State.Registers (Y_Register (ins))
+            then
+               CPU.Skip (State);
+            end if;
+         when Set_Address =>
+            State.Address_Register := Address (ins.Value);
+         when Random =>
+            State.Registers (X_Register (ins)) :=
+               Random_Byte.Random (Random_Generator) mod To_Byte (ins);
+         when Draw_Sprite =>
+            Draw_Sprite (X_Register (ins), Y_Register (ins),
+               To_Byte (ins) mod 16);
+         when Misc =>
+            case To_Byte (ins) is
+               when 16#07# =>
+                  State.Registers (X_Register (ins)) := State.Delay_Timer;
+               when 16#15# =>
+                  State.Delay_Timer := State.Registers (X_Register (ins));
+               when 16#1E# =>
+                  State.Address_Register := State.Address_Register +
+                     Address (State.Registers (X_Register (ins)));
+               when 16#55# =>
+                  CPU.Reg_Store (State, X_Register (ins));
+               when 16#65# =>
+                  CPU.Reg_Load (State, X_Register (ins));
+               when others => begin
+                  Ada.Text_IO.Put_Line ("Unknown misc instruction!");
+                  Ada.Text_IO.Put_Line (Opcode_Value'Image (ins.Value));
+                  delay 1.0;
+                  Video.Finish;
+               end;
+            end case;
+         when others => begin
+            Ada.Text_IO.Put_Line ("Unknown instruction class!");
+            Ada.Text_IO.Put_Line (Opcode_Class'Image (ins.Class));
+            delay 1.0;
+            Video.Finish;
+         end;
+      end case;
+   end Run_Step;
+begin
+   if Ada.Command_Line.Argument_Count /= 1 then
+      Ada.Text_IO.Put_Line ("usage: adachip <.c8 file>");
+   else
+      Video.Initialize;
+      Random_Byte.Reset (Random_Generator);
+      CPU.Load_File (State, Ada.Command_Line.Argument (1));
+
+      while Video.Is_Running loop
+         Video.Display;
+
+         if State.Delay_Timer > 0 then
+            State.Delay_Timer := State.Delay_Timer - 1;
+         end if;
+
+         for I in 0 .. Steps_Per_Frame loop
+            Run_Step;
+         end loop;
+      end loop;
+   end if;
+end Ada_Chip;