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Add support for DOS 1.x floppy images. Also a small fix to the FAT drive FindNext so it doesn't require a terminating entry in the root directory.

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3906
This commit is contained in:
ripsaw8080 2015-03-13 13:52:48 +00:00
parent 235939e277
commit 1363f5ed68
1 changed files with 47 additions and 0 deletions
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47
src/dos/drive_fat.cpp
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@ -680,6 +680,49 @@ fatDrive::fatDrive(const char *sysFilename, Bit32u bytesector, Bit32u cylsector,
}
loadedDisk->Read_AbsoluteSector(0+partSectOff,&bootbuffer);
/* Check for DOS 1.x format floppy */
if ((bootbuffer.mediadescriptor & 0xf0) != 0xf0 && filesize <= 360) {
Bit8u sectorBuffer[512];
loadedDisk->Read_AbsoluteSector(1,&sectorBuffer);
Bit8u mdesc = sectorBuffer[0];
/* Allowed if media descriptor in FAT matches image size */
if ((mdesc == 0xfc && filesize == 180) ||
(mdesc == 0xfd && filesize == 360) ||
(mdesc == 0xfe && filesize == 160) ||
(mdesc == 0xff && filesize == 320)) {
/* Create parameters for a 160kB floppy */
bootbuffer.bytespersector = 512;
bootbuffer.sectorspercluster = 1;
bootbuffer.reservedsectors = 1;
bootbuffer.fatcopies = 2;
bootbuffer.rootdirentries = 64;
bootbuffer.totalsectorcount = 320;
bootbuffer.mediadescriptor = mdesc;
bootbuffer.sectorsperfat = 1;
bootbuffer.sectorspertrack = 8;
bootbuffer.headcount = 1;
bootbuffer.magic1 = 0x55; // to silence warning
bootbuffer.magic2 = 0xaa;
if (!(mdesc & 0x2)) {
/* Adjust for 9 sectors per track */
bootbuffer.totalsectorcount = 360;
bootbuffer.sectorsperfat = 2;
bootbuffer.sectorspertrack = 9;
}
if (mdesc & 0x1) {
/* Adjust for 2 sides */
bootbuffer.sectorspercluster = 2;
bootbuffer.rootdirentries = 112;
bootbuffer.totalsectorcount *= 2;
bootbuffer.headcount = 2;
}
}
}
if ((bootbuffer.magic1 != 0x55) || (bootbuffer.magic2 != 0xaa)) {
/* Not a FAT filesystem */
LOG_MSG("Loaded image has no valid magicnumbers at the end!");
@ -920,6 +963,10 @@ nextfile:
entryoffset = dirPos % 16;
if(dirClustNumber==0) {
if(dirPos >= bootbuffer.rootdirentries) {
DOS_SetError(DOSERR_NO_MORE_FILES);
return false;
}
loadedDisk->Read_AbsoluteSector(firstRootDirSect+logentsector,sectbuf);
} else {
tmpsector = getAbsoluteSectFromChain(dirClustNumber, logentsector);