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Re: TNDLPT : Tandy Sound on parallel port

Posted on 2018-01-09, 22:21

This will only work with 386 and up, but a very welcome addition! Nope, it can be made to work on 8088 as well. Remember that we patched various games to replace out C0h, al with int C0h? So that we could redirect them to another port on ATs, because of the second DMA controller? For the TNDLPT we …

Re: OPL2LPT

Posted on 2018-01-03, 22:16

First time is not really important because a typical benchmark loop does not measure the latency of a single iteration. What is important is that the total latency for all iterations will be close to results for unpatched code. Which depends on two things: 1) The additional overhead of the first …

Re: OPL2LPT

Posted on 2018-01-03, 20:38

You could also use two OPL2LPTs on a single LPT, by using an additional address line, I suppose. Using OPL3 on an LPT will be no different in that respect.

Re: OPL2LPT

Posted on 2017-12-29, 10:42

I tried to just do it by cycle counting, but I think I ended up with a mistake in calculation. Plus as you mentioned the QX-10 is displaying the clock on screen, so presumably that's causing an interrupt occasionally (I could disable that clock in the settings). Well, that would mean there's some …

Re: End of NVIDIA Driver Support for 32-bit Operating Systems

Posted on 2017-12-28, 09:04

in Milliways
How does 64 bit systems manage 32 bits apps? Does DirectX get 32 bit calls and get wraps them into 64 bit drivers or does it need some kind of 32 bit pseudo-driver? What about OpenGL? Yes, there's a sort of 32-bit pseudo-driver, which interfaces with the 64-bit low-level driver. So, NV is not …

Re: Which programming language?

Posted on 2017-12-27, 14:31

in Milliways
I work with llvm a lot in my job. I wonder if adding a target for DOS executables (16bit) out of LLVM/clang would be useful for anyone? Reenigne is working on a 16-bit DOS version of gcc: https://blogs.mentor.com/embedded/blog/2017/04/01/announcing-sourcery-codebench-lite-for-ia16/ The biggest …

Re: Which programming language?

Posted on 2017-12-27, 11:13

in Milliways
Sure. There were two questions, which languages were used, and which languages are most useful, so I think caution is warranted. I think it depends a lot on whether you are targeting 32-bit systems or not. 32-bit compilers have been used for many years after DOS became obsolete, and as such, you …

Re: OPL2LPT

Posted on 2017-12-26, 22:21

Games will be able to measure port read latency properly and the rest will work the same. Not really. The first time you still pass through the virtualization layer, with extra overhead for the patching. Besides, how many games, if any, do even measure port latency at all? It doesn't make sense. …

Re: Which programming language?

Posted on 2017-12-26, 13:34

in Milliways
Inline assembly sure, but that assumes you've exhausted algorithmic optimizations, for which you'll first have rethought many of your modern intuitions about programming and not just the choice of language. For something like a 486, and depending on the task, fairly modern pure c++ sans assembly …

Re: OPL2LPT

Posted on 2017-12-26, 11:19

I'll end up making one once I've written some software to play more than just one static note, need to either find an adlib tracker format that's not very demanding (might just use Reality Adlib Tracker without effects) or just write something of my own. I'd like to get it playing some Christmas …

Re: OPL2LPT

Posted on 2017-12-23, 12:45

noop wrote: I proposed to patch reads from the Adlib port with reads from any other port that is not being intercepted by the driver Because most ISA reads generate roughly the same delay. And what advantage would that have over handling the delay inside the write?

Re: OPL2LPT

Posted on 2017-12-22, 18:21

No, re-read the discussion. No, inform yourself who you're talking to, instead of assuming I know nothing about AdLib programming and delays. Also, read my posts more clearly. The whole problem is that making reads too fast breaks some software, and it is not port reads themselves that are too slow …

Re: OPL2LPT

Posted on 2017-12-22, 11:14

dr.zeissler wrote: I think it behaves like a COVOX which means it will work in real dos, but not within win9x/2k/xp, or am I wrong here? True, but if there are AdLib drivers for these versions of Windows, they could be patched.

Re: OPL2LPT

Posted on 2017-12-22, 11:12

If it's a read, it's patched out. I think it is better to redirect read to any other port, so the delays remains as before. Easier said than done though. It's probably best to patch out the reads, and instead perform the delays in the TSR itself, after the writes. The problem with redirecting ports …

Re: *START HERE* SoftMPU 1.9 - Software Intelligent MPU-401 Emulator

Posted on 2017-12-16, 20:22

in SoftMPU
Any chance to get this thing working on a 286 ? (probably not) Not as-is, but perhaps it is possible to use the same trick we used for Tandy: Patch 'out' instructions to 'int' instructions, so that an interrupt handler, installed by a TSR, will be called. Downside is of course that every game will …

Re: IBM Music Feature Card/Yamaha FB-01

Posted on 2017-12-14, 12:54

I have made an experimental TSR named SoftIMFC: https://www.dropbox.com/s/tnlrda2j3sfwhy6/SoftIMFC.zip?dl=0 It is similar in nature to SoftMPU: it uses EMM386 or QEMM386 to virtualize the ports of the IMFC and intercept and reads and writes. It then runs these through the same emulation routines I …

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