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Fail* directories reorganized, Code-cleanup (-> coding-style), Typos+comments fixed.

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git-svn-id: https://www4.informatik.uni-erlangen.de/i4svn/danceos/trunk/devel/fail@1321 8c4709b5-6ec9-48aa-a5cd-a96041d1645a
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adrian
2012-06-08 20:09:43 +00:00
parent d474a5b952
commit 2575604b41
866 changed files with 1848 additions and 1879 deletions
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simulators/bochs/bios/notes Normal file
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####################
# Read Disk Sector #
####################
System programming:
-------------------
(Int 13h, ah=2)
in 1f7 until BSY cleared
out 1f2, AL # number of sectors
out 1f3, cl (bits 0-5) # starting sector number
out 1f4, ch # cylinder number bits 0..7, 0 based
out 1f5, cl (bits 6,7) & dh (bits 6,7) # cyl, bits 8..9, 10..11
out 1f6, dh (bits 0..3) --> bits 0..3 # head number
dh (bits 4..5) --> ??? # head number
dl (bit 0) --> bit 4 # drive number
out 1f7, 0x20 # read sectors command normal
Drive response:
---------------
* drive sets the busy bit in Status Reg to 1
* if command parameters are wrong:
> drive sets the aborted-command bit in the Error register and
error bit in the Status register to 1.
> Drive also sets the busy bit in the Status register to 0.
> Drive then generates an interrupt to the system.
* else:
> drive executes an implied seek to desired track and
reads sectors into sector buffer
> when sector buffer is filled and the data is ready to be
transferred, the drive sets the data-request bit to 1, sets
the busy bit to 0, and generates an interrupt.
> on a single-sector transfer, after the system has transferred
the data, the drive sets the data-request bit and the busy bit to 0.
> on a multiple-sector transfer, after the system has transferred
the first sector of data, the drive sets the data-request bit to 0,
and the busy bit to 1. When each subsequent sector is ready to be
transferred, the drive sets the data-request bit to 1, the busy bit to 0,
and generates an interrupt. When the system has tranferred the last sector,
the drive sets the data-request bit and busy bit to 0.