Re: I think there's a bug in the 256 color palette of DOSBox in graphics mode 0x13

Posted on 2024-05-25, 19:26

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by videogamer555

in DOSBox Development

in DOSBox Development

15 goes into 255 exactly 17 times VGA DAC RGB register values are not 8-bit, they're 6-bit, and 15 does not divide evenly into 63. IBM, and therefore DOSBox, uses these RGB register values for indexes 16-31 of the 256-color default palette: 00,00,00 05,05,05 08,08,08 0B,0B,0B 0E,0E,0E 11,11,11 14, …

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I think there's a bug in the 256 color palette of DOSBox in graphics mode 0x13

Posted on 2024-05-25, 04:59

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by videogamer555

in DOSBox Development

in DOSBox Development

When I do Ctrl+F5 to save a screenshot, it saves a PNG in indexed palette mode, with a copy of the VGA palette being the palette for the PNG file. However the values for indexes 16 to 31 (the grayscale entries part of the palette) seem to be incorrect. For example at index 17, it should be the …

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Re: DOSBox debugger

Posted on 2024-05-25, 04:32

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by videogamer555

in DOSBox Development

in DOSBox Development

jmarsh wrote on 2024-05-23, 22:14: Regular DOSBox builds do not use static SDL libraries. Ok. Sorry. I thought it was statically linked in the normal version because I didn't remember seeing the DLLs there, but upon looking at it again, I see it does have the DLLs there.

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Re: DOSBox debugger

Posted on 2024-05-23, 21:02

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by videogamer555

in DOSBox Development

in DOSBox Development

I just downloaded dosbox-74-3-debug.exe and it says it's missing SDL DLLs. It seems the normal version of DOSBox was compiled with static SDL libraries, but the debug version of DOSBox is compiled only with import libraries mode, expecting external DLLs to be supplied separately. Also it's expecting …

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Questions about installing Windows95 in DosBox

Posted on 2023-03-14, 06:04

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by videogamer555

in DOSBox Games/Apps

in DOSBox Games/Apps

So I did this in the way I've read other people say worked for them. I extracted all of the contents of the CD to the folder DosBox is using for the C drive. I made sure to set the emulated DOS version to 7.10 (Windows 95 expects the version to be over 7.00) and then ran Setup.exe with the command …

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Re: Several VESA video modes aren't working in DOS Box

Posted on 2023-02-22, 04:19

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by videogamer555

in DOSBox Development

in DOSBox Development

"For some reason" Haven't the reasons already been stated? Have you checked against a real S3 video card that DOSBox emulates? I didn't know that was a real type of video card. I thought that was just a term used by the DosBox devs for the generic a SVGA card they were coding for DosBox. I figured …

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Re: Several VESA video modes aren't working in DOS Box

Posted on 2023-02-22, 00:41

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by videogamer555

in DOSBox Development

in DOSBox Development

This is not how VESA BIOSes behaved back in the 90s. S3 graphics chips used a 4 bytes per pixel in 16M color modes, mostly because that's required for VRAM based cards with direct DAC data path. If you look at this table in Wikipedia from the VESA article, you will see that 24bit modes and 32bit …

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Re: Several VESA video modes aren't working in DOS Box

Posted on 2023-02-21, 06:50

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by videogamer555

in DOSBox Development

in DOSBox Development

jmarsh wrote on 2023-02-20, 13:32: https://www.vogons.org/download/file.php?mode=view&id=158016 […] Show full quote Where can I download a copy of PCPBench? I Googled it, and all I get are blog and forum posts where people mention using it. No download links.

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Re: Several VESA video modes aren't working in DOS Box

Posted on 2023-02-21, 05:59

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by videogamer555

in DOSBox Development

in DOSBox Development

It's already been explained to you that VBE2.0 made defined modes deprecated and they should not be relied upon. Deal with it or any app you write may break on any real card that defines modes differently from what you expect. My understanding is that all this means is that they should not be …

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Re: Guide to the DOSBox debugger

Posted on 2023-02-21, 05:23

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by videogamer555

in DOSBox Guides

in DOSBox Guides

[*]Unlike the debug version, heavydebug does not use INT 3 to realize breakpoints. This way, they cannot be removed. So if you want to use breakpoints, heavydebug is the better choice.[/list] Wait how is that an extra feature? If the heavy debug version takes AWAY the ability to use INT 3 …

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Re: DOSBox debugger

Posted on 2023-02-21, 05:03

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by videogamer555

in DOSBox Development

in DOSBox Development

if you have experience with debugging you can try the DOSBox debugger It can be downloaded from: DOSBox debugger EXE 0.74-3 DOSBox debugger EXE 0.74-2 DOSBox debugger EXE 0.74 For information on how to use it: Guide to debugger I have a question about DOSBox Debugger. How do I make it respond to …

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Re: Several VESA video modes aren't working in DOS Box

Posted on 2023-02-20, 21:43

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by videogamer555

in DOSBox Development

in DOSBox Development

Ok. But shouldn't DosBox support all the documented modes, just in case there's some game out there that uses them? I thought VESA was supposed to have a mandatory minimum set of modes that needed to be included in a graphics card to be considered VESA compliant. And it would make sense if it was …

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Re: Several VESA video modes aren't working in DOS Box

Posted on 2023-02-20, 11:55

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by videogamer555

in DOSBox Development

in DOSBox Development

... Any VESA compliant BIOS should support at least the following video modes (not all of which are currently supported in DOS Box). This is definitely not true. From VBE 2.0 (that DosBox emulates) there is no such thing as mandatory video mode number support. And even VBE 1.x had not specified …

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Several VESA video modes aren't working in DOS Box

Posted on 2023-02-20, 06:27

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by videogamer555

in DOSBox Development

in DOSBox Development

After testing out some of the different video modes listed here https://en.wikipedia.org/wiki/VESA_BIOS_Extensions in the debugger version of DS Box, I found many of these graphics modes were failing. In some cases, DOS Box itself was calling it an illegal mode (though the return value from the VESA …

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Re: So how many colors does video mode 10h actually support?

Posted on 2022-11-30, 06:16

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by videogamer555

in DOSBox General

in DOSBox General

How about PC Junior video modes (modes 0x08, 0x09, and 0x0A)? The first 2 support 16 colors, and the third supports 4 colors. Do the 16 color PCJr modes work like EGA, with separate bit planes? Or do they use a single bit plane for all the image data (like CGA 4-color modes, but with 16 colors …

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Re: So how many colors does video mode 10h actually support?

Posted on 2022-11-30, 06:11

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by videogamer555

in DOSBox General

in DOSBox General

Mode 10h is supposed to support 16 colors. To store 640x350 pixels with 16 colors, you need 112 kilobytes of video RAM. The basic configuration of EGA only shipped with 64KB of video RAM. The EGA BIOS configured the EGA card in a creative way, so that instead of 4 planes of 16KB the video memory …

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So how many colors does video mode 10h actually support?

Posted on 2022-11-29, 22:00

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by videogamer555

in DOSBox General

in DOSBox General

Over on http://www.techhelpmanual.com/114-video_modes.html it says it's an EGA and VGA mode that supports 4 or 16 colors. So what selects how many colors it supports? Is it 4 colors on an EGA graphics card and 16 colors on a VGA graphics card? Also how are its colors addressed? I'm sure that the 16 …

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Re: Does DOSBox support 32-bit "unreal" mode?

Posted on 2022-10-18, 08:39

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by videogamer555

in DOSBox Development

in DOSBox Development

Ok, so I tried it again on the latest version of Dosbox Debuger (which is posted at the top of this thread DOSBox debugger) and it doesn't seem to consider it to be an illegal instruction.

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Re: DOSBox ECE (for Windows & Linux)

Posted on 2022-10-18, 08:23

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by videogamer555

in DOSBox Development

in DOSBox Development

Please post all questions concerning DOSBox ECE in this thread for now on, so we can keep other threads tidy and on topic! I compiled a build of DOSBox ECE for Linux. Consider it highly experimental, since I only run Linux in a VM, I can't test all the features, because the VM is lacking hardware …

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Re: Does DOSBox support 32-bit "unreal" mode?

Posted on 2022-10-18, 08:10

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by videogamer555

in DOSBox Development

in DOSBox Development

since DosBox doesn't explicitly recognize unreal mode, it thinks the instruction is invalid (though it executes the instruction correctly anyway). I don't know about DOSBox internals but you don't need any special mode to execute `mov [edi],al`. As long as edi is not too big (that is, edi == di), …

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