Re: problems with DOS and TASM

Posted on 2011-08-19, 05:12

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by japheth

in Milliways

in Milliways

> I was setting up the video screen (b800h) as the buffer, ES=B800h This is a *very* bad idea for floppy disk reads - because FD I/O uses (legacy) DMA. You must use standard conventional memory and, to be absolutely safe, you should ensure that your buffer doesn't cross a 64 kB border!

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Re: Start cmd.exe inside DosBox

Posted on 2011-08-13, 18:57

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by japheth

in DOSBox Games/Apps

in DOSBox Games/Apps

There's also a DOS port of MuPDF - it may accept a lot more PDF files than the ancient Acrobat thing. http://www.unet.univie.ac.at/~a0503736/php/dr … 011-02-20-MUPDF

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Re: Vista limits DPMI servers to a max of 32mb

Posted on 2008-05-21, 17:53

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by japheth

in Release Announcements

in Release Announcements

Miki Maus wrote: Can this program be used to fix Syndicate Wars eating up all free memory in Windows XP? I don't know. If this is a DOS program, it's possible. In case it doesn't do what's expected - the source is included and it has full control about the amount of DPMI memory an application can …

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Re: Vista limits DPMI servers to a max of 32mb

Posted on 2008-05-21, 08:49

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by japheth

in Release Announcements

in Release Announcements

Hi, I updated the tool mentioned above, and source code is now included as well. I don't know if it helps with Vista, I don't own that "OS", but for XP it works. If someone is willing to do tests in Vista with it, I'll be glad to help. http://www.japheth.de/Download/hxntvdm.zip

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Re: KYRANDIA 3 - No Sound

Posted on 2007-11-03, 12:22

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by japheth

in DOS

in DOS

The only way to get Kyrandia 3 working properly with sound appears to be to use DOSBOX. It is supposed to run on Windows, but that was Windows 95. With XP or later it is best to use DOSBOX. No. I have a SB Live and can run Kyrandia 3 in FreeDOS with sound. Running it in a Win98 DOS box works as …

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Re: A Little Bug Report

Posted on 2007-09-19, 06:39

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by japheth

in DOSBox Development

in DOSBox Development

but looks a bit strange, since a IRQ in the VM might destroy the register copy saved onto the stack. Maybe trace the stack of msdos, if they skip the register saving completely. In that case you'd remove the SaveRegs calls in int21/4b functions, and the RestoreReg ones in int21/4c The register …

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Re: A Little Bug Report

Posted on 2007-09-18, 08:31

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by japheth

in DOSBox Development

in DOSBox Development

Qbix wrote: the +18 is probably to counter the the -20 at the start of dos.cpp ? no, it's just to revert the change done to this register inside SaveRegisters().

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Re: A Little Bug Report

Posted on 2007-09-18, 06:26

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by japheth

in DOSBox Development

in DOSBox Development

> You can use something like that: Thanks! However, AFAICS this modification affects the called program's stack only. The issue I was talking about is the value of SP of the caller. EDIT: this modification works: if (flags==LOAD) { SaveRegisters(); /* added */ DOS_PSP callpsp(dos.psp()); /* Save the …

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A Little Bug Report

Posted on 2007-09-17, 09:58

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by japheth

in DOSBox Development

in DOSBox Development

Hello, there is a small bug in DosBox's support for int 21h, ax=4B01h. The stack pointer (SP) is modified once the new program has terminated. This isn't the case in other DOSes. I don't know if any game is affected by this, probably not. test case: http://www.japheth.de/Download/dbbug.zip

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Re: Question about DosBox's IOCTL emulation

Posted on 2007-04-06, 16:35

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by japheth

in DOSBox Development

in DOSBox Development

thanks for explanation!

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Question about DosBox's IOCTL emulation

Posted on 2007-04-06, 08:18

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by japheth

in DOSBox Development

in DOSBox Development

Hi, The DosBox's docs are telling that the IOCTL API is implemented ("almost"). So I was curious and loaded an external EMM (Jemm386, which can be loaded from the command line) into DosBox. It loaded without errors and the cpu was in v86-mode then, but all attempts to communicate with the "EMMXXXX0" …

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Re: problem with cpu detection code inside dosbox

Posted on 2006-12-08, 09:52

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by japheth

in DOSBox Development

in DOSBox Development

it seems that DosBox has a problem with the trace flag: it is cleared in the copy of the Flags register onto the stack, but is set in Flags just before the POPF. Since the latter is the relevant value, a debug exception should occur, but DosBox might give the value of Flags after POPF a higher …

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problem with cpu detection code inside dosbox

Posted on 2006-12-07, 20:39

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by japheth

in DOSBox Development

in DOSBox Development

Hello, the following code snippet to detect the cpu type has a problem running under DEBUG in DosBox: pushf pop ax or ah,70h push ax popf ;<--- here DEBUG looses control of debuggee in DosBox pushf pop ax could this be fixed? used DosBox CVS build from 12.11.2006 for the test.

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Re: How to increase xms memory size over 63 MB?

Posted on 2006-09-28, 11:14

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by japheth

in DOSBox General

in DOSBox General

wd wrote: 1024mb surely will not work, your program can't access that much for sure (the dos interfaces are rather limited). XMS 3.0 has no problems with 1024 MB or 2048 MB. The dos interfaces probably aren't as limited as you might think 😀.

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write opcodes not emulated (yet) to the log window

Posted on 2006-05-11, 18:26

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by japheth

in DOSBox Development

in DOSBox Development

Wouldn't it be good to display opcodes which aren't emulated - for whatever reason - but just skipped to the log window. This won't cost speed and may give hints why one or another application doesn't run. opcode "INVLPG" is an example which I have in mind. IIRC it is one of two opcodes which were …

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Re: int 15h, ax=e801

Posted on 2006-05-09, 18:02

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by japheth

in DOSBox Development

in DOSBox Development

thanks!

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Re: int 15h, ax=e801

Posted on 2006-05-09, 07:44

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by japheth

in DOSBox Development

in DOSBox Development

> So, was the HXGUI made mainly for DOSBOX? it was made to support SDL apps, and one of the first apps to test was qemu. After qemu worked, there was nothing to do to make dosbox running. Another thing was hx running inside dosbox. This didn't work. Some issues are solved now so it works now to some …

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Re: int 15h, ax=e801

Posted on 2006-05-07, 20:05

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by japheth

in DOSBox Development

in DOSBox Development

> Not sure if the HXGUI is going to be used by anyone for any real-world > purposes I wanted to run DosBox in DOS!

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Re: read/only pages not protected in DosBox?

Posted on 2006-04-18, 08:46

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by japheth

in DOSBox Games/Apps

in DOSBox Games/Apps

> all because those would greatly reduce the speed. that's understandable, but at least optionally (possibly not at runtime if it is a speed issue, but at compiletime) it would be good to have these things included.

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read/only pages not protected in DosBox?

Posted on 2006-04-14, 17:47

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by japheth

in DOSBox Games/Apps

in DOSBox Games/Apps

Hello, I'm using DosBox for testing some protected-mode apps and just discovered that pages marked as readonly can be written to from ring 3 protected mode, which on a real cpu is not possible. Is this by design or is this a bug? I can imagine that some dos-extender apps may rely on getting page …

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