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Questions tagged [vga]

Anything related to Video Graphics Array (VGA) video card and related standards. Usually used to tag questions about VGA compatible hardware (VGA connectors, cables, monitors, etc.) or VGA specifications (VGA resolutions, VGA video modes, etc.)

Anything related to Video Graphics Array (VGA) video card and related standards. Usually used to tag questions about VGA compatible hardware (VGA connectors, cables, monitors, etc.) or VGA specifications (VGA resolutions, VGA video modes, etc.).

See the VGA Wikipedia page.

218 questions
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Where is the textmode video buffer if it isn't at 0xB8000?

About 15 years ago, I used to amuse myself and annoy my CS teacher by writing bad code that would directly modify the text on the monitor. This was/is easily done by accessing video memory at 0xB8000 on VGA-equipped PC-compatibles. Fast forward to…
Drew Shafer
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iPad VGA Connector - Mirror screen in own Application?

Is it possible to mirror the Screen over the VGA Connector? Can't find anything about this.
x2on
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14
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What is The Memory Address of Character Table In DOS?

What is the address of character table in DOS where we can create new fonts and symbols by manipulating the pixels of the each character? I know to change it with BIOS interrupts, but I only need the memory address of the character table in dos for…
user776475
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12
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2 answers

Does modern PC video hardware support VGA text mode in HW, or does the BIOS emulate it (with System Management Mode)?

What really happens on modern PC hardware booted in 16-bit legacy BIOS MBR mode when you store a byte such as '1' (0x31) into the VGA text (mode 03) framebuffer at physical linear address B8000? How slow is a mov [es:di], eax store with the MTRR…
Peter Cordes
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9
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1 answer

Graphics mode in assembly 8086

I have a variable that is called average and in my DATASEG, it changes every time because the user enters a different input every time. What I want to do is to go to the graphics mode (VGA) and then print there Your average is: and then the average…
Tomer Cahal
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7
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2 answers

VGA controller with VHDL

I'm trying to learn VHDL programming with some books and an Altera DE1 development kit from Terasic. The issue here is that I am trying to program a VGA controller for work with a resolution of 640x480 (although my screen is an TFT LCD with…
osuarez
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6
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1 answer

Assembly does reading a plane in mode x needs a different output to the VGA ports from writing?

1I am writing in TASM 3.0 on DosBox 0.74 and I am trying to write in Mode x (Tweaked 13h, unchained mode 13), and I ran into a problem, how you can see in the image, every line is printed, but in every line, every group of four pixels only the color…
Erik Gelfat
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6
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1 answer

Mode X in Assembly x86-16, Why is plane 1 not printing and all the other planes are not in the correct order?

I am writing in TASM 3.0 on DosBox 0.74 and I am trying to write in Mode x (Tweaked 13h, unchained mode 13), but here you can see in the image, it's not quite right. It seems that plane 1 (second plane) is not printing at all, and all the others are…
Erik Gelfat
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6
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6 answers

Using UIScreen to drive a VGA display - doesn't seem to show the UIWindow?

HI there, I'm trying to use UIScreen to drive a separate screen with the VGA dongle on my iPad. Here's what I've got in my root view controller's viewDidLoad: //Code to detect if an external display is connected to the iPad. NSLog(@"Number of…
Peter Hajas
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5
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What is the best way to clear the screen in 32-bit x86 assembly language (Video mode 13h)

So at the moment i am copying a screenbuffer (screenbuffer db 64000 DUP(0)) to the video memory (which starts at 0a0000h) to clear the screen. But i was wondering if it is better to just setup the video mode again like this: mov ax, 13h int…
T Snake
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5
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2 answers

Meaning of bytes in Intel GMA950 private buffer, in VGA text mode

When working on the text screen (mode 3, 80x25) both the usual Video Buffer at B800h and the Linear Frame Buffer (LFB) near the end of the 4GB address space are active. I've found that for each character cell on the display, the LFB uses 8 bytes.…
Sep Roland
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5
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Assembly x86 video mode

I'm trying to create some basic drawing routines in assembly (NASM). Looking at the x86 BIOS interrupt table, I've found the 10h interrupt that offers some video manipulation services. Using it, I've managed to come up with a routine to draw a…
Mateus
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5
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will linux emit event when monitor connect with D-sub connector?

I want to write a software, when monitor connect with D-sub connector, this software will pop-up, and ask user to mirror monitor or extend monitor. but i doesn't find any event emit when d-sub connect. on Windows vista, if you connect a monitor,…
yurenju
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How to write into the VGA memory (not video buffer, memory) to display a logo on screen, in Linux?

I would like to write into the VGA memory (video memory, not buffer) from user space by mmap-ing in user space and sending the address to kernel space where, i would use pfn remap to map those mmap-ed address to the vga memory (i'll get the address…
neo
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5
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How do I access memory addresses directly in Ada?

So I'm new to Ada, and I'm attempting to write a kernel in it, but I cannot seem to find any good information on how to do this properly. In C, I would write: unsigned char* videoram = (char*) 0xB8000; videoram[0] = 65; to access the video ram…
MarkHammons
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