typedef struct _MEMORYSTATUS {
  DWORD  dwLength;
  DWORD  dwMemoryLoad;
  SIZE_T dwTotalPhys;
  SIZE_T dwAvailPhys;
  SIZE_T dwTotalPageFile;
  SIZE_T dwAvailPageFile;
  SIZE_T dwTotalVirtual;
  SIZE_T dwAvailVirtual;
}MEMORYSTATUS, *LPMEMORYSTATUS;    

struc MEMORYSTATUS {
        .:
        .dwLength               rd 1
        .dwMemoryLoad           rd 1
        .dwTotalPhys            rq 1    ; SIZE_T
        .dwAvailPhys            rq 1    ; SIZE_T
        .dwTotalPageFile        rq 1    ; SIZE_T
        .dwAvailPageFile        rq 1    ; SIZE_T
        .dwTotalVirtual         rq 1    ; SIZE_T
        .dwAvailVirtual         rq 1    ; SIZE_T
        .. = $ - .

 macro .GlobalMemoryStatus \{
          lea rcx,[.]
         call [GlobalMemoryStatus]
   \}
}

mstat MEMORYSTATUS

mstat.GlobalMemoryStatus
cmp [mstat.dwLength],mstat..
jnz .err    

struc MSG {
      .:
      .hwnd           rq 1
        .message        rd 2
        .wParam         rq 1
        .lParam         rq 1
        .time           rd 2
        .pt             POINT
       .. = $ - .
}    

On computers with more than 4 GB of memory, the MEMORYSTATUS structure can return incorrect information, reporting a value of –1 to indicate an overflow. If your application is at risk for this behavior, use the GlobalMemoryStatusEx function instead of the GlobalMemoryStatus function.