loader.c

  VOID *vendor_table;
  Status = EfiGetSystemConfigurationTable(&gEfiAcpiTableGuid,&vendor_table);
  struct rsdp *acpi_rsdp = (struct rsdp *)vendor_table;
  Print(L"Signature:");
  UINTN i;
  for(i=0;i<6;i++){
    Print(L"%c",acpi_rsdp->sig[i]);
  }
  Print(L"\n");
  Print(L"XSDT Address: %08x\n",acpi_rsdp->XsdtAddress);
  
  Status =  gBS->AllocatePages(AllocateAddress,EfiLoaderData,1,&BootParamAddr);
  if(EFI_ERROR(Status)){
    Print(L"Can not allocate boot param address\n");
  }
  struct xsdt *acpi_xsdt = (struct xsdt *)acpi_rsdp->XsdtAddress;
  struct madt *acpi_madt;
  struct boot_param *boot_param = (struct boot_param *)BootParamAddr;

  UINTN entries = (acpi_xsdt->h.len - sizeof(acpi_xsdt->h)) / 8;
  for(i=0;i<entries;i++){
    struct sdt_header *h = (struct sdt_header *)acpi_xsdt->pointer_others[i];
    if(!AsciiStrnCmp(h->sig,"APIC",4)){
      Print(L"Signature:");
      UINTN j;
      for(j=0;j<4;j++){
        AsciiPrint("%c",h->sig[j]);
      }
      Print(L"\n");
      Print(L"MADT Address: %p\n",h);
      acpi_madt = (struct madt *)h;
      boot_param->madt_addr = (UINT64)(boot_param+sizeof(struct boot_param));
      CopyMem((VOID *)(boot_param->madt_addr),(VOID *)h,h->len);
      Print(L"MADR_ADDR: %x \n",boot_param->madt_addr);
    }
  }