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fixed CHS computation bug

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svn path=/trunk/; revision=8637
This commit is contained in:
Vizzini 2004-03-11 06:48:22 +00:00
parent 6ef65a3872
commit 8438bc1293
1 changed files with 10 additions and 4 deletions
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14
reactos/drivers/storage/floppy/readwrite.c
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@ -48,7 +48,6 @@
* TODO: Handle split reads and writes across multiple map registers
* TODO: Break up ReadWritePassive and handle errors better
* TODO: Figure out data rate issues
* TODO: I think RWComputeCHS is bugified
* TODO: Media type detection
* TODO: Figure out perf issue - waiting after call to read/write for about a second each time
* TODO: Figure out specify timings
@ -346,7 +345,7 @@ static NTSTATUS NTAPI RWComputeCHS(PDRIVE_INFO IN DriveInfo,
* NOTES:
* - Lots of ugly typecasts here
* - Sectors are 1-based!
* - FIXME: I think this routine is still bugified a bit
* - This is really crummy code. Please FIXME.
*/
{
ULONG AbsoluteSector;
@ -356,13 +355,15 @@ static NTSTATUS NTAPI RWComputeCHS(PDRIVE_INFO IN DriveInfo,
/* First calculate the 1-based "absolute sector" based on the byte offset */
ASSERT(!(DiskByteOffset % DriveInfo->DiskGeometry.BytesPerSector)); /* FIXME: Only handle full sector transfers atm */
/* AbsoluteSector is zero-based to make the math a little easier */
AbsoluteSector = DiskByteOffset / DriveInfo->DiskGeometry.BytesPerSector; /* Num full sectors */
/* Cylinder number is floor(AbsoluteSector / SectorsPerCylinder) */
*Cylinder = (CHAR)(AbsoluteSector / SectorsPerCylinder);
/* Head number is 1 if the sector within the cylinder > SectorsPerTrack; 0 otherwise */
*Head = AbsoluteSector % SectorsPerCylinder > DriveInfo->DiskGeometry.SectorsPerTrack ? 1 : 0;
/* Head number is 0 if the sector within the cylinder < SectorsPerTrack; 1 otherwise */
*Head = AbsoluteSector % SectorsPerCylinder < DriveInfo->DiskGeometry.SectorsPerTrack ? 0 : 1;
/*
* Sector number is the sector within the cylinder if on head 0; that minus SectorsPerTrack if it's on head 1
@ -372,6 +373,11 @@ static NTSTATUS NTAPI RWComputeCHS(PDRIVE_INFO IN DriveInfo,
KdPrint(("floppy: RWComputeCHS: offset 0x%x is c:0x%x h:0x%x s:0x%x\n", DiskByteOffset, *Cylinder, *Head, *Sector));
/* Sanity checking */
ASSERT(*Cylinder <= DriveInfo->DiskGeometry.Cylinders.QuadPart);
ASSERT(*Head <= DriveInfo->DiskGeometry.TracksPerCylinder);
ASSERT(*Sector <= DriveInfo->DiskGeometry.SectorsPerTrack);
return STATUS_SUCCESS;
}