MiSTer FPGA Forum

Better I stay with your advice to use ref 0002 , the game also works: exit77: mov bp, sp rcr byte ptr [bp+8], 1 rol byte ptr [bp+8], 1 ; insert error CF on stack neg ah pop bp pop ds retf 0002 ... although the music of it and Turbo Debugger still do not work, they are other bugs, perhaps it also has something to do with interruptions ... I will rev...

Edit: From my recollection, this inconsistency in handling the interrupt flag (some forcing it set, some restoring it) was endemic in interrupt handlers (except those for IRQs of course). Most handlers forced it set and returned with RETF 0002h instead of IRET. It's usual to have to disable ints after an interrupt call if you want them off, even i...

EDIT: Come to think about it, the bug might be in these read-modify-write instructions: rcr byte ptr [bp+8], 1 rol byte ptr [bp+8], 1 ; insert error CF on stack It should not be accessing the second byte of the flags, where the interrupt flag is stored, because it's a byte access. Worth taking a look though. Very well seen too! I will take a look ...

Good finding. IRET should definitely restore interrupts to the state stored in the stack. If they were disabled before executing INT 13h, they should be disabled after IRET. If they were enabled, they should be enabled after IRET. If that's not the case, then the implementation of IRET is buggy. Of course it's possible to fiddle with the stack and...

By 3C do you mean 44C3? Sorry for not being more specific. By 3C, I mean the divisor you were commenting on at address 44C2... It is seen that until the loop is reached, it is correctly decremented. There are many possible hypotheses, it's hard to put the finger on one. The interrupt flag may be a possible culprit, for example, especially if you s...

INT 1Ch should be called by the BIOS INT 08h handler. Is it possible that that isn't happening with the BIOS you're using? If the timer is to blame and not the BIOS, it's possible that it works, but the speed is much slower than the creators anticipated. Have you waited for a while just in case? I have verified that 3C is decremented until reachin...

I had incorrectly fetched the content of CS: [44C3], actually I was getting it from the DS segment, other than CS. Now I get it fine, and it contains 1, as it should be ... I keep investigating the decrement of CS: [44C2]. It may have something to do with the timer timings.

I have made an analysis of a game that does not work in this core , the Tapper . In this case, we get to the menu screen and it is possible to modify the options, but when starting it, it hangs at this point: [...] There's something weird in your analysis. Position 44C3h gets modified by the INT 1Ch (Timer Tick) handler, which is located at 3758h....

First of all, happy new year! Let's see if this year is better than 2021. I have made an analysis of a game that does not work in this core , the Tapper . In this case, we get to the menu screen and it is possible to modify the options, but when starting it, it hangs at this point: IMG_20211231_173919.jpg If we debug it, we have that the point wher...

If you can run this CGA 8088MPH demo, I will be impressed: https://www.youtube.com/watch?v=hNRO7lno_DM And for those that are confused: https://trixter.oldskool.org/2015/04/07/8088-mph-we-break-all-your-emulators/ I know this demo and the answer is no, not at the moment at least. There are several things to fix in this project and the one it is ba...

Beta 0.2

• EMS memory support for the megabyte available in 2MB versions.
• Fixed some bugs.
• Refactoring and cleaning of project files.

Changes to my GitHub repository:

https://github.com/spark2k06/next186lit ... f8aa48a7cd

Soon EMS available for the 2Mb version of SRAM of the ZXUno and ZXUnCore, thanks to Lo-Tech's LTEMM manager, modified to support 1Mb of memory with 64 pages. We will also have a lot of conventional memory available making use of high memory

All traces of access to the old VGA support of the Next186 have been removed, but aside from the pending improvements, one of the important points is the bug fixes. I have already identified a few games that are not playable, because either they do not work or if they do they do not go well, they crash, etc ...: Army Moves: Graphic glitches Capitan...

ZXUno PCXT CGA (Beta 0.1) First Beta version. 2MB version of SRAM with 1MB addressable. Changes on GitHub: https://github.com/spark2k06/next186lite_graphics_gremlin/commit/e5e36c917f861cc81108b310d5957982597b5ac6 https://www.youtube.com/watch?v=nYM2x__3_P4 TODO Software and game debugging for continuous BIOS and core improvement. EMS memory suppor...

Edit: Wait, ackerman is right, it's a problem of the core, with lack of segment wrap-around. In an XT, if you attempt to write to e.g. FFFF:0010 you're actually writing to address 0, due to wrap-around caused by the 20-bit address bus of 8086/8088. That's what the A20 gate is about: it's a setting, configurable via software in PC-AT and greater, t...

Thanks for the information, I did not know that format. I have carried out a fix in the management of the instruction cache, specifically after the execution of MOV memory access instructions. Although the problem has been solved for me with a different stub used in a version of the AlleyCat game (whose executable occupies 61Kb), it has not been th...

So if you're going Tandy, will Tandy sound replace the adlib? Will Deskmate and DOS be rom bootable? Tandy Graphics initially only, and only because it comes standard on TubeTime's Graphics Gremlin project... let us also remember for the moment, partially. For sound, my preference is Adlib . And on a ZXUno , with limited resources, I would be luck...

First of all, thank you for your hard work ! I've been crossing my fingers since a while hoping to see coming out of the ground, a Tandy 1000 core. As your main motivation was CGA & Tandy, does it mean that we can expect also a Tandy 1000 compatible core ? Is a Hercules 720*348 monochrome graphic card possible as well ? To me this is as import...

akeley wrote: ↑Sat Nov 27, 2021 2:19 pm

spark2k06 wrote: ↑Fri Nov 26, 2021 8:39 am if I see that it is possible, composite video using color burst.

Fingers crossed.

At the moment it is not implemented, let's see if I first fix several issues that are still pending ... but I have it in my to do list

First version already available (Spanish):

https://zxuno.com/forum/viewtopic.php?f=56&t=6261

I will provide the sources soon.

Thanks a lot for your work Why do you have remove ega,mcga modes ? It’s xt related I replace the BIOS interrupt 10h with the original ones from a PCXT, like the Micro8088: https://github.com/skiselev/8088_bios/blob/master/video.inc BIOS functions for EGA is an extension of it. But mostly, I remove the EGA / MCGA implementations from the core due t...

I'm the one who is developing this version of Next186 for ZXUno. In this case I'm adding the FPGA TubeTime's Graphics Gremlin project to have CGA and Tandy modes, the latter partially, I have removed the rest of the modes that the original core had: EGA, MCGA... As the CGA implementation is based on the Motorola 6845 chip, I have seen the opportuni...

MDA / CGA card project for the ISA port, where Verilog sources are shared, I think they could be used for PC cores in MiSTer

https://github.com/schlae/graphics-grem ... in/verilog

Another option, for 15Khz and composyte_sync=0:

viewtopic.php?t=1711

Not everything that comes from china or Aliexpress is bad, and it is also possible to find trusted sellers on that sales platform.

jotego wrote: ↑Wed Dec 30, 2020 10:26 am By the way, two people with no-failures for any of these MRA files told me they lived in areas with low population density (and hence less RF noise).

How curious, we will have to put the MiSTer in a faraday cage .

You might be interested in my MonochromeRGB solution, in addition to having VGA2SCART, you have interesting filters ... take a look at the post I published:

viewtopic.php?t=1711

Very cool! Just curious, does it perform hue rotation (esp regarding the "interesting palette changes")? Thanks! The circuit is very simple and is based entirely on resistors. Both in color mode (palettes) and in monochrome mode, the different tones are achieved with the different combinations of the rotary switches: https://cdn.hackaday...

Hi, I have developed a device that will allow us to enjoy the MiSTer playing with its RGB output to make interesting combinations of monochrome screens, regardless of the core used, in addition to the common ones of old Green, Amber and B&W monitors: https://lh3.googleusercontent.com/pw/ACtC-3dolK3tHUTBb-5R_CnTHCsAM104lJ_DBpk5cyGozajDPB1mOZdbq_...

Hi, I have designed a backplane in Mini-ITX format with Kicad and I have shared it as a GPL3 license, being the Open Source Hardware project. This backplane is initially intended to be used with Sergey Kiselev's Micro8088 or xi8088 PC clones, among others system powered by x86 architecture. However, other old systems could also be developed using F...