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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 Input => case To_Byte (ins) is
when 16#9E# =>
if Video.Key_Down
(Video.Key (State.Registers (X_Register (ins)) mod 16))
then
CPU.Skip (State);
end if;
when 16#A1# =>
if Video.Key_Up
(Video.Key (State.Registers (X_Register (ins)) mod 16))
then
CPU.Skip (State);
end if;
when others => null;
end case;
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#18# => null; -- TODO: sound
when 16#1E# =>
State.Address_Register := State.Address_Register +
Address (State.Registers (X_Register (ins)));
when 16#29# =>
State.Address_Register :=
Address (State.Registers (X_Register (ins))) * 5;
when 16#33# => begin
State.Memory (State.Address_Register) :=
State.Registers (X_Register (ins)) / 100;
State.Memory (State.Address_Register + 1) :=
State.Registers (X_Register (ins)) / 10 mod 10;
State.Memory (State.Address_Register + 2) :=
State.Registers (X_Register (ins)) mod 10;
end;
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;
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