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DMA Problems

Posted: Sun Mar 23, 2003 10:11 am
by FlashBurn
These are my dma functions. The Problem is now that I get these errors from Bochs:

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[DMA  ] write to command register: value(14h) not 0x00
[DMA  ] write to command register: value(10h) not 0x00
What make I wrong?

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Re:DMA Problems

Posted: Sun Mar 23, 2003 10:18 am
by Pype.Clicker
well, it looks like BOCHS do not like you to put some non-nul value in the 0x08 (dma command) register ...

i dunno where it comes from, but you should maybe re-read your doc ...

Re:DMA Problems

Posted: Sun Mar 23, 2003 11:36 am
by FlashBurn
OK, there seems not to be a problem with dma. Now I?ve read a sector from the floppy with dma. But the data is in the wrong order.

This is the data:

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4E000FE9
And so it has to be:

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E90F004E
Why is the data in the wrong order?

Re:DMA Problems

Posted: Mon Mar 24, 2003 2:13 am
by Pype.Clicker
hey, remember on intel, numbers are encoded with the least-significant byte first . so if you try to display 0x12345678 as a string (or if you look at it in memory), it will show as
0x78 0x56 0x34 0x12 ...