mos6502-delphi/C64/Source/C64.pas
2017-03-09 15:24:15 +01:00

197 lines
3.8 KiB
ObjectPascal

unit C64;
interface
uses
System.Classes, WinApi.Messages, MOS6502;
const
WM_SCREEN_WRITE = WM_USER + 0;
CIA1 = $DC00;
KEY_TRANSLATION = '1£+9753'#8+#8'*piyrw'#13+#0';ljgda'#0+'2'#0'-0864'#0+' '#0'.mbcz'#0+#0'=:khfs'#0+'q'#0'@oute'#0+
#0'/,nvx'#0#0+'!'#0#0')'#39'%#'+#0+#0#0#0#0#0#0#0#13+#0']'#0#0#0#0#0#0+'"'#0#0#0'(&$'#0+' '#0'>'#0#0#0#0#0+
#0#0'['#0#0#0#0#0+#0#0#0#0#0#0#0#0+#0'?<';
type
TC64 = class;
TC64Thread = class(TThread)
private
C64: TC64;
protected
public
procedure Execute; override;
constructor Create(C64Instance: TC64);
end;
TC64 = class(TMOS6502)
private
Thread: TC64Thread;
TimerHandle: Integer;
LastKey: Char;
procedure BusWrite(Adr: Word; Value: Byte);
function BusRead(Adr: Word): Byte;
function KeyRead: Byte;
protected
KeyMatrix: Array[0 .. 7, 0 .. 7] of Byte;
Memory: PByte;
InterruptRequest: Boolean;
public
WndHandle: THandle;
constructor Create;
destructor Destroy; override;
procedure LoadROM(Filename: String; Addr: Word);
procedure Exec;
procedure SetKey(Key: Char; Value: Byte);
end;
implementation
uses
System.SysUtils, Winapi.Windows, WinApi.MMSystem;
{ TC64 }
procedure TimerProcedure(TimerID, Msg: Uint; dwUser, dw1, dw2: DWORD); pascal;
var
C64: TC64;
begin
C64 := TC64(dwUser);
if C64.Status and $04 = 0 then // if IRQ allowed then set irq
C64.InterruptRequest := True;
end;
function TC64.BusRead(Adr: Word): Byte;
begin
Result := Memory[Adr];
end;
procedure TC64.BusWrite(Adr: Word; Value: Byte);
begin
// test for I/O requests
case Adr of
CIA1:
begin
// Handle keyboard reading
Memory[Adr] := Value;
Memory[CIA1 + 1] := KeyRead;
end;
CIA1 + 5: // Timer
if TimerHandle = 0 then
TimerHandle := TimeSetEvent(34, 2, @TimerProcedure, DWORD(Self), TIME_PERIODIC);
end;
if (Adr >= $A000) then // treat anything above as ROM
Exit;
Memory[Adr] := Value;
// video RAM
if (Adr >= $400) and (Adr <= $07E7) then
PostMessage(WndHandle, WM_SCREEN_WRITE, Adr - $400, Value);
end;
constructor TC64.Create;
begin
inherited Create(BusRead, BusWrite);
// create 64kB memory table
GetMem(Memory, 65536);
Thread := TC64Thread.Create(Self);
end;
destructor TC64.Destroy;
begin
if TimerHandle <> 0 then
Timekillevent(TimerHandle);
Thread.Terminate;
Thread.WaitFor;
FreeMem(Memory);
inherited;
end;
procedure TC64.Exec;
begin
Reset;
Thread.Start;
end;
function TC64.KeyRead: Byte;
var
Row, Col, Cols: Byte;
begin
Result := 0;
Cols := Memory[CIA1];
for Col := 0 to 7 do
if Cols and (1 shl Col) = 0 then // a 0 indicates a column read
for Row := 0 to 7 do
if KeyMatrix[7 - Col, Row] = 1 then
Result := Result + (1 shl Row);
Result := not Result;
end;
procedure TC64.LoadROM(Filename: String; Addr: Word);
var
Stream: TFileStream;
begin
Stream := TFileStream.Create(Filename, fmOpenRead);
try
Stream.Read(Memory[Addr], Stream.Size);
finally
Stream.Free;
end;
end;
procedure TC64.SetKey(Key: Char; Value: Byte);
var
KeyPos: Integer;
begin
KeyPos := Pos(Key, KEY_TRANSLATION) - 1;
if KeyPos >= 0 then
begin
// always release last key on keypress
if Value = 1 then
begin
SetKey(LastKey, 0);
LastKey := Key;
end;
if KeyPos > 63 then // set right shift on/off
begin
KeyMatrix[1, 4] := Value;
Dec(KeyPos, 64);
end;
KeyMatrix[KeyPos mod 8, KeyPos div 8] := Value;
end;
end;
{ TC64Thread }
constructor TC64Thread.Create(C64Instance: TC64);
begin
inherited Create(True);
C64 := C64Instance;
end;
procedure TC64Thread.Execute;
begin
while (not Terminated) do
begin
if C64.InterruptRequest then
begin
C64.InterruptRequest := False;
C64.IRQ;
end;
C64.Step;
Sleep(0);
end;
end;
end.