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FDC Read without INT and DMA
Posted: Tue Mar 07, 2006 4:01 pm
by Seven11
Is it possible to read sectors from the floppy without using interrupt and DMA? The reason I'm using is because I'm trying to add a small floppy driver to my bootloader (not bootsector) and I don't want any extra code in it.
Re:FDC Read without INT and DMA
Posted: Tue Mar 07, 2006 4:22 pm
by OZ
hi,
to access the floppy drive in your bootloader you may use bios functions - with interrupt 13 afaik- well you better take a look at ralf browns interrupt list (should be linked in the faq) to be sure. This will only work in real mode, but that shouldn't be a problem as you want to use it in your boot loader.
If you meant these bios functions with your "without interrupt and dma" then you could write a fdc driver that just uses drive polling instead of interrupts and single byte transfer instead of letting the dma do it for you. (Hope I remember the spec right, but I think one could set it up for polling)
Re:FDC Read without INT and DMA
Posted: Tue Mar 07, 2006 6:47 pm
by Dex4u
OZ wrote:If you meant these bios functions with your "without interrupt and dma" then you could write a fdc driver that just uses drive polling instead of interrupts and single byte transfer instead of letting the dma do it for you. (Hope I remember the spec right, but I think one could set it up for polling)
Your right OZ, according to all doc i have read you can do single byte transfer using floppy, but i have try and alot of other people have tryed, but i have not heard of anyone getting it to work.
If it a case of size then your best bet is BIOS, if you are in realmode. A simple pmode driver not using BIOS, but using DMA would be about 1k not including buffers.
This bootloader Has welL commented nasm code, if using BIOS.
http://alexfru.chat.ru/epm.html#bootprog
Re:FDC Read without INT and DMA
Posted: Mon Mar 13, 2006 10:13 am
by asmboozer
wish to know how to access flopy without bios service int 13
Re:FDC Read without INT and DMA
Posted: Mon Mar 13, 2006 11:23 am
by Dex4u
Re:FDC Read without INT and DMA
Posted: Mon Mar 13, 2006 11:25 am
by Pype.Clicker
asmboozer wrote:
wish to know how to access flopy without bios service int 13
That's more simple; there are plenty of driver/tutorials that tell you that. We even have guidelines
in the FAQ