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flat assembler > OS Construction > VESA 4f00h - how to read information from buffer?

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user7991



Joined: 29 May 2016
Posts: 1
VESA 4f00h - how to read information from buffer?
Hello there!
VESA documentation tells that when I call 4f00h function I have to write to di register the address of info buffer which is recommended to be 512 bytes for VESA 2 and higher.
And there are 16h-19h and 1Ah-1Dh offsets in this buffer that contain far pointers to vendor name string and videocard name string.
Please help how to extract this information from these pointers and how to do it when I work in protected mode? Can I make my info buffer 256 bytes instead of 512 and read these strings? THANK YOU!!!
Documentation, page 28:
http://www.petesqbsite.com/sections/tutorials/tuts/vbe3.pdf
Post 29 May 2016, 19:34
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 14674
Location: Origae-6
I would presume that "far pointer" means a segment and an offset.

Code:
les si,[vesa_buffer+0x16;get name string

And I would expect that shrinking the buffer to 256 bytes would probably be okay if the function accepts the maximum length as an input (I didn't check).
Post 30 May 2016, 04:13
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