Re: repne/repnz movsw: Invalid instruction prefix mystery

Posted on 2019-08-20, 10:03

by

by jmarsh

in DOSBox General

in DOSBox General

Technically replacing F2 A5 with F3 A5 would be correct because the former is undefined, but intel/amd aren't likely to change behaviour of it because it's been mistakenly used in a lot of MBR code.

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Re: repne/repnz movsw: Invalid instruction prefix mystery

Posted on 2019-08-20, 09:40

by

by jmarsh

in DOSBox General

in DOSBox General

Note that repe uses the same prefix as rep (0xF3), so the given example wouldn't work as expected. Regardless the repe/repne prefixes only check the Z flag when the string instruction updates the flags (only the count register is tested before the first execution) so if the flags are never updated …

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Re: GeForce2 Fan Cable Replacement

Posted on 2019-08-20, 06:01

by

by jmarsh

in Marvin \ Video

in Marvin \ Video

When people started complaining about the noise.

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Re: CD Burning Software for Windows 98

Posted on 2019-08-18, 10:31

by

by jmarsh

in Marvin \ Software

in Marvin \ Software

Try a 3.x/4.x version of CDRWIN.

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Re: CHS values + drive size limitations

Posted on 2019-08-17, 10:29

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

red_avatar wrote: less wasted space due to how FAT32 works. Not sure what you mean here, FAT32 doesn't support smaller cluster sizes so it would only ever be less efficient.

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Re: Capacitors for old LCD power supply questions...

Posted on 2019-08-16, 23:54

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There are normally some 470uf caps that you will want to replace as well as the remaining 1000uf caps (not just the ones that are obviously defective). Otherwise the same issue will reoccur.

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Re: Strange behaviour from SD to IDE adapter

Posted on 2019-08-16, 13:54

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

That's not going to help if there is data corruption occurring, as shown by the filename inconsistencies. Try it on a different machine, if the same thing happens throw it in the bin. SD2IDE and SD2SATA adapters always seem to be poor quality unless you spend big bucks.

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Re: Looking for the rare Dune (Cryo) non interactive Demodisk

Posted on 2019-08-13, 23:43

by

by jmarsh

in Milliways

in Milliways

Top image looks more like Sting than the apparent movie adaption...

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Re: GeForce2 Fan Cable Replacement

Posted on 2019-08-12, 15:45

by

by jmarsh

in Marvin \ Video

in Marvin \ Video

Or just plug the fan into a spare 3-pin connector on the motherboard.

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Re: Supermicro P54VL-PCI unexpectedly dead

Posted on 2019-08-11, 20:58

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Well monitoring (to detect activity and prevent the system suspending) I can understand. It makes a lot more sense than waking.

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Re: Supermicro P54VL-PCI unexpectedly dead

Posted on 2019-08-11, 20:21

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

How can a video card (an output device) wake a system?

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Re: Supermicro P54VL-PCI unexpectedly dead

Posted on 2019-08-11, 19:07

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There's jumpers to select between VLB/ISA video, did you adjust them when testing with the ISA card?

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Re: Can you identify this NIC for me?

Posted on 2019-08-08, 11:43

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Acer 5220 hardware setting quick reference: a. Bit-Mapped Options for DIP Switchblock SW1 Switch Default Number Function Setting ------------------------------------------------- 01 Memory segment address A17 1 02 Memory segment address A16 1 03 Memory segment address A15 0 04 Memory segment address …

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Re: Unable to make Dosbox run on Windows 10

Posted on 2019-08-07, 12:00

by

by jmarsh

in DOSBox General

in DOSBox General

What window previews pop up when you hover the mouse cursor over the dosbox icon on the taskbar?

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Re: Unable to make Dosbox run on Windows 10

Posted on 2019-08-07, 10:42

by

by jmarsh

in DOSBox General

in DOSBox General

It might be off-screen for some odd reason, maybe you ran it on a secondary display in the past and it's remembering the old location for example.

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Re: Best option for remote desktop to Linux from Win98SE or 2000?

Posted on 2019-07-31, 05:59

by

by jmarsh

in Marvin \ Software

in Marvin \ Software

Better off installing an x11 server and redirecting application's display to the windows box.

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Re: Lowest CPU to play MP3s?

Posted on 2019-07-24, 14:25

by

by jmarsh

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Integer decoding isn't really faster, it just enabled decoding on CPUs without FPU. Mostly it was only for smartphones before armv7 became widespread.

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Re: Their Finest hour install through Dosbox - disk space error

Posted on 2019-07-24, 09:29

by

by jmarsh

in DOSBox Games/Apps

in DOSBox Games/Apps

It's probably something else going wrong with copying files and the installer incorrectly assumes the problem is a lack of free space. DOSBox's internal copy command doesn't handle wildcards very well so you might want to try installing under freedos or similar.

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Re: CD-ROM LBA vs MSF vs play addresses and pregap/postgap?

Posted on 2019-07-23, 14:41

by

by jmarsh

in PC Emulation

in PC Emulation

A mode 1 sector is 2048 bytes. A mode 2 sector/audio frame is 2352 bytes.

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Re: GTA1 - crash when changing video mode

Posted on 2019-07-23, 13:13

by

by jmarsh

in DOSBox Games/Apps

in DOSBox Games/Apps

The "Illegal read from 1018afab, CS:IP 2e0:1018afaa" messages mean execution jumped to an invalid address/unmapped page so DOSBox would be fetching/translating 0xFF instead of valid opcodes.

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