1) Sync EdkCompatibilityPkg with EDK 1.04. The changes includes:

[mirror_edk2.git] / EdkCompatibilityPkg / Sample / Tools / Source / GenBootsector / GetDrvNumOffset.c

#include "fat.h"\r
#include <stdio.h>\r
\r
INTN\r
GetDrvNumOffset (\r
  IN VOID *BootSector\r
  )\r
{\r
  FAT_BPB_STRUCT  *FatBpb;\r
  UINTN           RootDirSectors;\r
  UINTN           FATSz;\r
  UINTN           TotSec;\r
  UINTN           DataSec;\r
  UINTN           CountOfClusters;\r
\r
  FatBpb  = (FAT_BPB_STRUCT *) BootSector;\r
\r
  //\r
  // Check FAT type algorithm from FAT spec\r
  //\r
  RootDirSectors = ((FatBpb->Fat12_16.BPB_RootEntCnt * sizeof(FAT_DIRECTORY_ENTRY)) +\r
                    (FatBpb->Fat12_16.BPB_BytsPerSec - 1)) / FatBpb->Fat12_16.BPB_BytsPerSec;\r
\r
  if (FatBpb->Fat12_16.BPB_FATSz16 != 0) {\r
    FATSz = FatBpb->Fat12_16.BPB_FATSz16;\r
  } else {\r
    FATSz = FatBpb->Fat32.BPB_FATSz32;\r
  }\r
  if (FATSz == 0) {\r
    fprintf (stderr, "ERROR: FAT: BPB_FATSz16, BPB_FATSz32 - 0, expected - Non-Zero\n");\r
    return -1;\r
  }\r
\r
  if (FatBpb->Fat12_16.BPB_TotSec16 != 0) {\r
    TotSec = FatBpb->Fat12_16.BPB_TotSec16;\r
  } else {\r
    TotSec = FatBpb->Fat12_16.BPB_TotSec32;\r
  }\r
  if (TotSec == 0) {\r
    fprintf (stderr, "ERROR: FAT: BPB_TotSec16, BPB_TotSec32 - 0, expected - Non-Zero\n");\r
    return -1;\r
  }\r
\r
  DataSec = TotSec - (\r
                      FatBpb->Fat12_16.BPB_RsvdSecCnt +\r
                      FatBpb->Fat12_16.BPB_NumFATs * FATSz +\r
                      RootDirSectors\r
                     );\r
\r
  CountOfClusters = DataSec / FatBpb->Fat12_16.BPB_SecPerClus;\r
\r
  if (CountOfClusters < FAT_MAX_FAT16_CLUSTER) {\r
    return (INTN) ((UINTN) &FatBpb->Fat12_16.BS_DrvNum - (UINTN) FatBpb);\r
  } else {\r
    return (INTN) ((UINTN) &FatBpb->Fat32.BS_DrvNum - (UINTN) FatBpb);\r
  }\r
}\r
\r