怎样让PC喇叭发出“Bi”的一声

因为NT下不能直接完成I/O操作，98下的API又不具备发出特定频率声音的能力，所以分开处理

Procedure Beep(nFreq,nDura: Word);
var
  VerInfo: TOSVersionInfo;
  nStart: DWord;
begin
  VerInfo.dwOSVersionInfoSize := SizeOf(VerInfo);
  GetVersionEx(VerInfo);
    if VerInfo.dwPlatformId = VER_PLATFORM_WIN32_NT then
      Windows.Beep(nFreq, nDura)
    else
    begin
      Asm
            push    bx
            in      al,     $61
            mov     bl,     al
            and     al,     3
            jne     @@Skip
            mov     al,     bl
            or      al,     3
            out     $61,    al
            mov     al,     $b6
            out     $43,    al
      @@Skip:   
            mov     ax,     nFreq
            out     $42,    al
            mov     AL,     ah
            out     $42,    al
            pop     bx
      end;
      nStart := GetTickCount;
      repeat
        Application.ProcessMessages;
      Until GetTickCount > nStart + nDura;
      asm
            IN      AL,     $61
            AND     AL,     $FC
            OUT     $61,    AL
      end;
    end;
end;

封装成函数,各种操作系统系统下通用~~~