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initdisk: further optimizations in CalculateFATData(): merging the FAT16 & FAT32
loops. fatfs: #if DEBUG fix. git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@1451 6ac86273-5f31-0410-b378-82cca8765d1b
This commit is contained in:
Bart Oldeman
parent
9e0b5e5bf6
commit
e3f90446b3
@ -253,8 +253,7 @@ f_node_ptr split_path(const char * path, f_node_ptr fnp)
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#ifdef DEBUG
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if (get_cds(path[0]-'A')->cdsFlags & CDSNETWDRV)
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{
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printf("split path called for redirected file: `%s'\n",
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fcbname);
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printf("split path called for redirected file: `%s'\n", path);
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return (f_node_ptr) 0;
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}
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#endif
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@ -412,15 +412,7 @@ VOID CalculateFATData(ddt * pddt, ULONG NumSectors, UBYTE FileSystem)
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defbpb->bpb_nreserved = 1;
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/* SEC_SIZE * DIRENT_SIZE / defbpb->bpb_ndirent + defbpb->bpb_nreserved */
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fatdata = NumSectors - (DIRENT_SIZE + 1);
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#ifdef DEBUG
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if (FileSystem != FAT12)
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DebugPrintf(("%ld sectors for FAT+data, starting with %d sectors/cluster\n", fatdata, defbpb->bpb_nsector));
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#endif
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switch (FileSystem)
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{
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case FAT12:
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case FAT12_LBA:
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if (FileSystem == FAT12 || FileSystem == FAT12_LBA)
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{
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unsigned fatdat;
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/* in DOS, FAT12 defaults to 4096kb (8 sector) - clusters. */
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@ -445,76 +437,27 @@ VOID CalculateFATData(ddt * pddt, ULONG NumSectors, UBYTE FileSystem)
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unsigned maxclust = (defbpb->bpb_nfsect * 2 * SEC_SIZE) / 3;
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if (maxclust > FAT12MAX)
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maxclust = FAT12MAX;
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printf(("FAT12: #clu=%u, fatlength=%u, maxclu=%u, limit=%u\n",
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clust, defbpb->bpb_nfsect, maxclust, FAT12MAX));
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printf("FAT12: #clu=%u, fatlength=%u, maxclu=%u, limit=%u\n",
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clust, defbpb->bpb_nfsect, maxclust, FAT12MAX);
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if (clust > maxclust - 2)
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{
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clust = maxclust - 2;
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printf(("FAT12: too many clusters: setting to maxclu-2\n"));
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printf("FAT12: too many clusters: setting to maxclu-2\n");
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}
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}
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#endif
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memcpy(pddt->ddt_fstype, MSDOS_FAT12_SIGN, 8);
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break;
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}
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case FAT16SMALL:
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case FAT16LARGE:
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case FAT16_LBA:
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{
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unsigned fatlength;
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else
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{ /* FAT16/FAT32 */
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CLUSTER fatlength, maxcl;
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unsigned long clust, maxclust;
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/* FAT16: start at 4 sectors per cluster */
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defbpb->bpb_nsector = 4;
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/* Force maximal fatdata=8387584 sectors (NumSectors=8387617)
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since with our only possible sectorsize (512 bytes) this is the
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maximum we can address with 64k clusters
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#clus*secperclus+#fats*fatlength=65517 * 128 + 2 * 256=8386688.
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max FAT16 size for FreeDOS = 4,293,984,256 bytes = 4GiB-983,040 */
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if (fatdata > 8386688ul)
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fatdata = 8386688ul;
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do
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{
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DebugPrintf(("Trying with %d sectors/cluster:\n",
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defbpb->bpb_nsector));
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unsigned fatentpersec;
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unsigned divisor;
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fatlength = (unsigned)cdiv(fatdata + 2 * defbpb->bpb_nsector,
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(SEC_SIZE/2) * defbpb->bpb_nsector + NFAT);
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/* Need to calculate number of clusters, since the unused parts of the
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* FATS and data area together could make up space for an additional,
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* not really present cluster. */
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clust = (fatdata - NFAT * fatlength) / defbpb->bpb_nsector;
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maxclust = (unsigned long)fatlength * (SEC_SIZE/2);
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if (maxclust > FAT16MAX)
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maxclust = FAT16MAX;
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DebugPrintf(("FAT16: #clu=%lu, fatlen=%u, maxclu=%lu, limit=%u\n",
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clust, fatlength, maxclust, FAT_MAGIC16));
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if (clust > maxclust - 2)
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{
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DebugPrintf(("FAT16: too many clusters\n"));
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clust = 0;
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}
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else if (clust <= FAT_MAGIC)
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{
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/* The <= 4086 avoids that the filesystem will be misdetected as having a
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* 12 bit FAT. */
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DebugPrintf(("FAT16: would be misdetected as FAT12\n"));
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clust = 0;
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}
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if (clust)
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break;
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defbpb->bpb_nsector <<= 1;
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}
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while (defbpb->bpb_nsector && defbpb->bpb_nsector <= MAXCLUSTSIZE);
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defbpb->bpb_nfsect = fatlength;
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memcpy(pddt->ddt_fstype, MSDOS_FAT16_SIGN, 8);
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break;
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}
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#ifdef WITHFAT32
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case FAT32:
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case FAT32_LBA:
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if (FileSystem == FAT32 || FileSystem == FAT32_LBA)
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{
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unsigned long fatlength, clust, maxclust;
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/* For FAT32, use the cluster size table described in the FAT spec:
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* http://www.microsoft.com/hwdev/download/hardware/fatgen103.pdf
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*/
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@ -532,29 +475,61 @@ VOID CalculateFATData(ddt * pddt, ULONG NumSectors, UBYTE FileSystem)
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defbpb->bpb_ndirent = 0;
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defbpb->bpb_nreserved = 0x20;
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fatdata = NumSectors - 0x20;
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fatentpersec = SEC_SIZE/4;
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maxcl = FAT32MAX;
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}
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else
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#endif
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{
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/* FAT16: start at 4 sectors per cluster */
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defbpb->bpb_nsector = 4;
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/* Force maximal fatdata=8387584 sectors (NumSectors=8387617)
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since with our only possible sectorsize (512 bytes) this is the
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maximum we can address with 64k clusters
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#clus*secperclus+#fats*fatlength=65517 * 128 + 2 * 256=8386688.
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max FAT16 size for FreeDOS = 4,293,984,256 bytes = 4GiB-983,040 */
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if (fatdata > 8386688ul)
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fatdata = 8386688ul;
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fatentpersec = SEC_SIZE/2;
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maxcl = FAT16MAX;
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}
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DebugPrintf(("%ld sectors for FAT+data, starting with %d sectors/cluster\n", fatdata, defbpb->bpb_nsector));
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do
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{
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fatlength = cdiv(fatdata + 2 * defbpb->bpb_nsector,
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(SEC_SIZE/4) * defbpb->bpb_nsector + NFAT);
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DebugPrintf(("Trying with %d sectors/cluster:\n", defbpb->bpb_nsector));
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divisor = fatentpersec * defbpb->bpb_nsector + NFAT;
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fatlength = (CLUSTER)((fatdata + (2 * defbpb->bpb_nsector + divisor - 1))/
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divisor);
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/* Need to calculate number of clusters, since the unused parts of the
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* FATS and data area together could make up space for an additional,
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* not really present cluster. */
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clust = (fatdata - NFAT * fatlength) / defbpb->bpb_nsector;
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maxclust = fatlength * (SEC_SIZE/4);
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if (maxclust > FAT32MAX)
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maxclust = FAT32MAX;
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DebugPrintf(("FAT32: #clu=%u, fatlen=%u, maxclu=%u, limit=%u\n",
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clust, fatlength, maxclust, FAT32MAX));
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maxclust = fatlength * fatentpersec;
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if (maxclust > maxcl)
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maxclust = maxcl;
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DebugPrintf(("FAT: #clu=%lu, fatlen=%lu, maxclu=%lu, limit=%lu\n",
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clust, fatlength, maxclust, maxcl));
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if (clust > maxclust - 2)
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{
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clust = 0;
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DebugPrintf(("FAT32: too many clusters\n"));
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DebugPrintf(("FAT: too many clusters\n"));
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}
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else if (clust <= FAT_MAGIC)
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{
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/* The <= 4086 avoids that the filesystem will be misdetected as having a
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* 12 bit FAT. */
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DebugPrintf(("FAT: would be misdetected as FAT12\n"));
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clust = 0;
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}
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if (clust)
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break;
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defbpb->bpb_nsector <<= 1;
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}
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while (defbpb->bpb_nsector && defbpb->bpb_nsector <= MAXCLUSTSIZE);
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#ifdef WITHFAT32
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if (FileSystem == FAT32 || FileSystem == FAT32_LBA)
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{
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defbpb->bpb_nfsect = 0;
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defbpb->bpb_xnfsect = fatlength;
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/* set up additional FAT32 fields */
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@ -564,9 +539,13 @@ VOID CalculateFATData(ddt * pddt, ULONG NumSectors, UBYTE FileSystem)
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defbpb->bpb_xfsinfosec = 1;
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defbpb->bpb_xbackupsec = 6;
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memcpy(pddt->ddt_fstype, MSDOS_FAT32_SIGN, 8);
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break;
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}
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else
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#endif
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{
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defbpb->bpb_nfsect = (UWORD)fatlength;
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memcpy(pddt->ddt_fstype, MSDOS_FAT16_SIGN, 8);
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}
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}
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pddt->ddt_fstype[8] = '\0';
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}
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