GN_Gmd, Get (read) the current machine system date in internal format
Register parameters
RST 20H, DEFW $1809
 IN: DE = 0, not allowed. DE = 1, not allowed. DE = 2, return system date in ABC. DE > 255, pointer to write machine date at (DE). OUT: If DE(in)>255 then DE = DE(in) + 3; ABC = ABC(in) If DE(in)<255 then DE = DE(in); ABC = result Registers changed after return: ......../IXIY same AFBCDEHL/.... different