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niki
Journeyman III

How videoRam and hardware acceleration connects?

Hi!

I have been reading the specification of the R*** models of radeon. It seems extensive, but not impossible.

There are one thing I can't understand.

The spec. tells: I send an command to the CP and the hardware draws on the screen. Can I understand that hardware writes through the DMA controller in the videoRam(VESA mode?), or the hardware outputs signals direct to the monitor through the video connector?

Sorry for the weird question. I am trying to program an hobby OS from the zero. I decided to not use any kind of third party libraries and write al the code in ASM. So I need to see clearly where physically the projected shapes go in the machine.

On the other hand I need to have it possibly clearer before to code something that can break some part of hardware.

Thanks in advance.

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2 Replies
pboudier
Staff

there are two separate concepts:

- drawing triangles/quads with the 3d engine

- displaying a buffer through the display controller

 

when you program the CP and initiate draw, then you control the 3d engine

which will write data in video memory.

if you want that memory to be what you see on your monitor, then you have

to program the ASIC through mmio (memory mapped IO) separately.

 

Pierre B.

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Thank you for the answer, Pierre!

I will search now through google to find more information about the ASIC. It is easier when one know what to search.

Bye!

niki

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