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I woud like to go public with my cycle accurate, open source SMS emulator TwoMbit.

TwoMbit is affected by bsnes and uses the libco threading module. One thread for each core.
The Gui is programmed in C# / WPF (compiled for .Net 4.0). The emulation core is a unmanaged c++ dll. I am using directx only, so the core depends on Windows.

The cpu can sync each Master to the vdp or apu, of course if it's needed only. for example before register writes.
The vdp can sync to the cpu each 2 Master.
The emulator itsself is not very speed optimized at time but I think the code readability is good.

What is emulated?
- bus hold times
- interrupt recognition one cpu cycle before opcode edge.
- sprite preprocessing during active display
- background display generation is parted and timed in name, color and pattern address select and ram load
- VDP delay
- cpu access window for active display
- emulating port 3e, can load bios or combine bios with game
- switchable between SMS 1 and 2

What is missing
- Lightgun support (input is already configurable in GUI)
- savestate support
- cheat support

- SG-1000, SC-3000 emulation (vdp mode 0 and 2 are already supported)
- game gear emulation
- additional yamaha sound chip

I would like to thank following people and groups:

- blargg for his blip_buffer and ntsc filter
- byuu for bsnes, which has inspired me
- Charles MacDonald for his docs and infos
- the people from smspower.org for the countless usefull discussions about the hardware

you can find the sources and a 32 or 64 bit binary at sourceforge
http://sourceforge.net/projects/twombit/

aww yeeeee, i love new emulators of my favorite consoles. i'll have to check it out, maybe it'll inspire me to work on vbsms+ some more.

downloadin' now.

Sweet project, using threads should definitively make things closer to how hardware parts are really running, which is nice.

However, from reading the code, I would say there is room for improvement (which is normal off course): some implementation choices are very dispatched/complex and most likely very far from how hardware is working internally, making the whole thing quite difficult to follow. It sometime feels like as if you started with a good idea (make the design simple & logic) but it ended utterly complicated because you kept adding new stuff to get things working. I don't know if I'm very clear but that's how i feel :-)

I think you should also take care of commenting your code, this kind of project is generally much more interesting for hardware documentation, but code only is not very readable by humans (yes, we all think good & simple code is readable, but from an external point of view, it's rarely the case), so please, comment it :-)

Otherwise, I like the overall object-oriented design and the (really !) insane granularity.

PiCiJi wrote

I woud like to go public with my cycle accurate, open source SMS emulator TwoMbit.

Great work! I'm glad we finally have an emulator that takes accuracy seriously. Thanks for sharing TwoMbit with the rest of us. :)

I just tried it and unfortunately I can't get it to load a game. The emu loads up fine but when I choose a game to load it crashes with a C++ runtime error (program asked to close in an unusual way).

EDIT: Forgot to say I'm using Win XP SP3 on a dual core (T5600) laptop.

All I ever get is:

Quote

---------------------------
Error
---------------------------
Sega Master System Emulation Core is missing, make sure the SmsCore.dll is in the same path as your application
---------------------------
OK
---------------------------

...when it is there.

Quote

Sega Master System Emulation Core is missing, make sure the SmsCore.dll is in the same path as your application

I had the problem on my old XP machine too. A program called Dependency Walker find out that a directx dll was missing. I have updated directx and it works.
For programming I have used the latest directx SDK from June 2010.

Quote

I just tried it and unfortunately I can't get it to load a game. The emu loads up fine but when I choose a game to load it crashes with a C++ runtime error (program asked to close in an unusual way).

hmm...hard to find out whats going wrong here. What OS you are using? You are using the 32 or 64 bit version of TwoMbit ? Maybe a directx update can solve the problem.
Are you trying to load a compressed file? If so, could you please try to load a uncompressed one.

I'm using 32 bit Win XP SP3 fully updated. My Direct X is up to date too. I was also using uncompressed ROMs (all (!) versions - good dumps).

I used th 32bit version of your emu. :)

Quote

My Direct X is up to date too.

directx 9.0c? After the update the version doesn't change. So are you sure you have the latest update ?

If you have the time, you could use Dependency Walker and load the SmsCore.dll
Then send me the red marked entries.

http://www.dependencywalker.com/

On this machine, it's missing D3DX9_43.DLL which is from the Feb 2010 DirectX refresh. I guess you need at least that version, but this is my work PC so I can't just install it :)

No problem. I used Dependancy Walker and have attached the dwi file. Hope this helps.

I also decided to re-install the latest version of DX just in case but the web installer said I was up to date. :)

SmsCore.zip (626.7 KB)

DWI File

Quote

On this machine, it's missing D3DX9_43.DLL which is from the Feb 2010 DirectX refresh. I guess you need at least that version, but this is my work PC so I can't just install it :)

Yes this dll was missing before updating directx.
Maybe an older directx SDK is a better choice. I will definitely throw better error messages, so the user find out what to do.

Quote

No problem. I used Dependancy Walker and have attached the dwi file. Hope this helps.

there is nothing wrong. It have to be some other problem. Are you able to configure the input (config / input) without crash?

Yeah, I can configure anything. All seems to work fine though it's kinda hard to tell sometimes with no 'Apply' button. It just crashes when I load any game.

Quote

some implementation choices are very dispatched/complex and most likely very far from how hardware is working internally

I am trying to see it more the way, what options has the software under a given hardware, no matter how it works internally. How could software find out it runs on a emulated system?

Quote

Yeah, I can configure anything. All seems to work fine though it's kinda hard to tell sometimes with no 'Apply' button. It just crashes when I load any game.

Sorry, at the moment I don't have an idea whats going wrong.

Worked fine on my Windows 7 machine once I d/l .net 4 framework and latest DX.

Always nice to see another new emulator - shall try this out tonight when I get home from work. I'm working on an SMS emulator of my own at the moment, but not striving for cycle-accuracy, as it is the first emulation project I've ever tried my hands at :-p

In your experience, how difficult was it to emulate everything to this degree of granularity? I've not looked at your source code yet, but I'm assuming as it's cycle-accurate it runs at the granularity of a machine click? To keep things simpler my Z80 core is only granular at the opcode level. Anyhow, good work, and this design interests me for future projects, I've done a great deal of reading on bsnes, and I agree it is inspiring :-)

nothing beats my master system though

Quote

how difficult was it to emulate everything to this degree of granularity?

with the threading library libco it's not much harder than an opcode based emulator to program. The challenge is to find out what is done each cycle, not to sync between the emulated processors.

Quote

I've done a great deal of reading on bsnes, and I agree it is inspiring :-)

same for me, I am reading bsnes for years.

At time I am leaving C# and Visual Studio in general. I give QT and gcc a try to get platform independence.

Good news for me as a Linux user then ;-) I'm using Java + Swing/Java2D for mine - nowhere near as quick as Qt, but quicker than people give it credit for and plenty fast enough for this :-)

v 1.0 beta -> v 1.0.1
[general]
- switched to gcc for compiler
- switched to QT 4.8 for Gui ( c# / .net is no more )
- build libsms (a cross-platform emulation library, so someone could build a gui without having to know the sms internals )

[emulation]
- gamegear emulation
- sg-1000 emulation
- emulating additional cart work ram (Ernie Els Golf, the castle, Othello)
- emulating bus contention
- emulating game gear bios
- emulating custom sram sizes (Shining force)
- emulating eeprom of the baseball series games
- emulating lightpahser, paddle (japanese and export), sportspad (japanese and export), 3d glasses, Terebi Oekaki
- emulating gear-2-gear at cycle level
- parallel communication (Squinky Tennis in micro machines, Primal Rage, ...)
- serial communication
- different baud rate settings
- emulating backward compatibillity of gamegear(mastergear) and sms
- emulating yamaha2413
- fex(zip, 7z, rar, gzip), bzip2, untar for compressed roms

https://sourceforge.net/projects/twombit/

[bugfixes]
- removed cache for irq detection, now irqs will be detected one cpu cycle before opcode edge ( simplified the overall process)
- fixed sample playback
- differentiate between sg and sms/gg vdp delay and access window behavior.

to do:

feature doings
- cheats
- savestates
- replace directx to make TwoMbit platform independant

accuracy doings
- sn76489: writing to regs will not processed without delay
- vdp: accurate access windows during sprite processing
- vdp: split sprite subprocessing in timed steps (like bg processing) and not one sprite at a time
- yamaha2413: sub sample accuracy

Author	Message
PiCiJi Joined: 05 Jun 2011 Posts: 36	new sms emulator: twoMbit Posted: Sun Nov 20, 2011 9:24 pm
PiCiJi Joined: 05 Jun 2011 Posts: 36	I woud like to go public with my cycle accurate, open source SMS emulator TwoMbit. TwoMbit is affected by bsnes and uses the libco threading module. One thread for each core. The Gui is programmed in C# / WPF (compiled for .Net 4.0). The emulation core is a unmanaged c++ dll. I am using directx only, so the core depends on Windows. The cpu can sync each Master to the vdp or apu, of course if it's needed only. for example before register writes. The vdp can sync to the cpu each 2 Master. The emulator itsself is not very speed optimized at time but I think the code readability is good. What is emulated? - bus hold times - interrupt recognition one cpu cycle before opcode edge. - sprite preprocessing during active display - background display generation is parted and timed in name, color and pattern address select and ram load - VDP delay - cpu access window for active display - emulating port 3e, can load bios or combine bios with game - switchable between SMS 1 and 2 What is missing - Lightgun support (input is already configurable in GUI) - savestate support - cheat support - SG-1000, SC-3000 emulation (vdp mode 0 and 2 are already supported) - game gear emulation - additional yamaha sound chip I would like to thank following people and groups: - blargg for his blip_buffer and ntsc filter - byuu for bsnes, which has inspired me - Charles MacDonald for his docs and infos - the people from smspower.org for the countless usefull discussions about the hardware you can find the sources and a 32 or 64 bit binary at sourceforge http://sourceforge.net/projects/twombit/

olaf Joined: 14 Oct 2006 Posts: 156 Location: US	Posted: Sun Nov 20, 2011 9:30 pm
olaf Joined: 14 Oct 2006 Posts: 156 Location: US	aww yeeeee, i love new emulators of my favorite consoles. i'll have to check it out, maybe it'll inspire me to work on vbsms+ some more. downloadin' now.

Eke Joined: 06 Feb 2009 Posts: 82 Location: Toulouse, France	Posted: Mon Nov 21, 2011 9:29 pm
	Sweet project, using threads should definitively make things closer to how hardware parts are really running, which is nice. However, from reading the code, I would say there is room for improvement (which is normal off course): some implementation choices are very dispatched/complex and most likely very far from how hardware is working internally, making the whole thing quite difficult to follow. It sometime feels like as if you started with a good idea (make the design simple & logic) but it ended utterly complicated because you kept adding new stuff to get things working. I don't know if I'm very clear but that's how i feel :-) I think you should also take care of commenting your code, this kind of project is generally much more interesting for hardware documentation, but code only is not very readable by humans (yes, we all think good & simple code is readable, but from an external point of view, it's rarely the case), so please, comment it :-) Otherwise, I like the overall object-oriented design and the (really !) insane granularity.

Charles MacDonald Joined: 28 Sep 1999 Posts: 1012	Posted: Tue Nov 22, 2011 3:30 am
Charles MacDonald Joined: 28 Sep 1999 Posts: 1012	PiCiJi wrote I woud like to go public with my cycle accurate, open source SMS emulator TwoMbit. Great work! I'm glad we finally have an emulator that takes accuracy seriously. Thanks for sharing TwoMbit with the rest of us. :)

Hot_Violet Joined: 04 Nov 2011 Posts: 74 Location: Scotland	Posted: Tue Nov 22, 2011 11:23 am
	I just tried it and unfortunately I can't get it to load a game. The emu loads up fine but when I choose a game to load it crashes with a C++ runtime error (program asked to close in an unusual way). EDIT: Forgot to say I'm using Win XP SP3 on a dual core (T5600) laptop.

Maxim Site Admin Joined: 19 Oct 1999 Posts: 8982 Location: London	Posted: Tue Nov 22, 2011 12:04 pm
	All I ever get is: Quote --------------------------- Error --------------------------- Sega Master System Emulation Core is missing, make sure the SmsCore.dll is in the same path as your application --------------------------- OK --------------------------- ...when it is there.

PiCiJi Joined: 05 Jun 2011 Posts: 36	Posted: Tue Nov 22, 2011 2:27 pm
PiCiJi Joined: 05 Jun 2011 Posts: 36	Quote Sega Master System Emulation Core is missing, make sure the SmsCore.dll is in the same path as your application I had the problem on my old XP machine too. A program called Dependency Walker find out that a directx dll was missing. I have updated directx and it works. For programming I have used the latest directx SDK from June 2010. Quote I just tried it and unfortunately I can't get it to load a game. The emu loads up fine but when I choose a game to load it crashes with a C++ runtime error (program asked to close in an unusual way). hmm...hard to find out whats going wrong here. What OS you are using? You are using the 32 or 64 bit version of TwoMbit ? Maybe a directx update can solve the problem. Are you trying to load a compressed file? If so, could you please try to load a uncompressed one.

Hot_Violet Joined: 04 Nov 2011 Posts: 74 Location: Scotland	Posted: Tue Nov 22, 2011 3:04 pm
	I'm using 32 bit Win XP SP3 fully updated. My Direct X is up to date too. I was also using uncompressed ROMs (all (!) versions - good dumps). I used th 32bit version of your emu. :)

PiCiJi Joined: 05 Jun 2011 Posts: 36	Posted: Tue Nov 22, 2011 4:22 pm
PiCiJi Joined: 05 Jun 2011 Posts: 36	Quote My Direct X is up to date too. directx 9.0c? After the update the version doesn't change. So are you sure you have the latest update ? If you have the time, you could use Dependency Walker and load the SmsCore.dll Then send me the red marked entries. http://www.dependencywalker.com/

Maxim Site Admin Joined: 19 Oct 1999 Posts: 8982 Location: London	Posted: Tue Nov 22, 2011 5:15 pm
	On this machine, it's missing D3DX9_43.DLL which is from the Feb 2010 DirectX refresh. I guess you need at least that version, but this is my work PC so I can't just install it :)

Hot_Violet Joined: 04 Nov 2011 Posts: 74 Location: Scotland	Posted: Tue Nov 22, 2011 6:17 pm
	No problem. I used Dependancy Walker and have attached the dwi file. Hope this helps. I also decided to re-install the latest version of DX just in case but the web installer said I was up to date. :) SmsCore.zip (626.7 KB) DWI File

PiCiJi Joined: 05 Jun 2011 Posts: 36	Posted: Tue Nov 22, 2011 8:00 pm
PiCiJi Joined: 05 Jun 2011 Posts: 36	Quote On this machine, it's missing D3DX9_43.DLL which is from the Feb 2010 DirectX refresh. I guess you need at least that version, but this is my work PC so I can't just install it :) Yes this dll was missing before updating directx. Maybe an older directx SDK is a better choice. I will definitely throw better error messages, so the user find out what to do. Quote No problem. I used Dependancy Walker and have attached the dwi file. Hope this helps. there is nothing wrong. It have to be some other problem. Are you able to configure the input (config / input) without crash?

Hot_Violet Joined: 04 Nov 2011 Posts: 74 Location: Scotland	Posted: Tue Nov 22, 2011 8:31 pm
	Yeah, I can configure anything. All seems to work fine though it's kinda hard to tell sometimes with no 'Apply' button. It just crashes when I load any game.

PiCiJi Joined: 05 Jun 2011 Posts: 36	Posted: Tue Nov 22, 2011 9:14 pm
PiCiJi Joined: 05 Jun 2011 Posts: 36	Quote some implementation choices are very dispatched/complex and most likely very far from how hardware is working internally I am trying to see it more the way, what options has the software under a given hardware, no matter how it works internally. How could software find out it runs on a emulated system? Quote Yeah, I can configure anything. All seems to work fine though it's kinda hard to tell sometimes with no 'Apply' button. It just crashes when I load any game. Sorry, at the moment I don't have an idea whats going wrong.

djbass Joined: 25 Jul 2007 Posts: 512 Location: Melbourne, Australia	Posted: Wed Nov 23, 2011 9:55 am
	Worked fine on my Windows 7 machine once I d/l .net 4 framework and latest DX.

PhilPotter Joined: 08 Nov 2011 Posts: 67 Location: United Kingdom	Good stuff :-) Posted: Mon Dec 12, 2011 10:56 am
	Always nice to see another new emulator - shall try this out tonight when I get home from work. I'm working on an SMS emulator of my own at the moment, but not striving for cycle-accuracy, as it is the first emulation project I've ever tried my hands at :-p In your experience, how difficult was it to emulate everything to this degree of granularity? I've not looked at your source code yet, but I'm assuming as it's cycle-accurate it runs at the granularity of a machine click? To keep things simpler my Z80 core is only granular at the opcode level. Anyhow, good work, and this design interests me for future projects, I've done a great deal of reading on bsnes, and I agree it is inspiring :-)

masterblaster Joined: 27 Nov 2011 Posts: 20	Posted: Tue Dec 13, 2011 12:30 pm
masterblaster Joined: 27 Nov 2011 Posts: 20	nothing beats my master system though

PiCiJi Joined: 05 Jun 2011 Posts: 36	Posted: Wed Dec 14, 2011 5:52 pm
PiCiJi Joined: 05 Jun 2011 Posts: 36	Quote how difficult was it to emulate everything to this degree of granularity? with the threading library libco it's not much harder than an opcode based emulator to program. The challenge is to find out what is done each cycle, not to sync between the emulated processors. Quote I've done a great deal of reading on bsnes, and I agree it is inspiring :-) same for me, I am reading bsnes for years. At time I am leaving C# and Visual Studio in general. I give QT and gcc a try to get platform independence.

PhilPotter Joined: 08 Nov 2011 Posts: 67 Location: United Kingdom	Cool :-) Posted: Wed Dec 14, 2011 9:13 pm
	Good news for me as a Linux user then ;-) I'm using Java + Swing/Java2D for mine - nowhere near as quick as Qt, but quicker than people give it credit for and plenty fast enough for this :-)

PiCiJi Joined: 05 Jun 2011 Posts: 36	update Posted: Sat Mar 31, 2012 12:20 pm
PiCiJi Joined: 05 Jun 2011 Posts: 36	v 1.0 beta -> v 1.0.1 [general] - switched to gcc for compiler - switched to QT 4.8 for Gui ( c# / .net is no more ) - build libsms (a cross-platform emulation library, so someone could build a gui without having to know the sms internals ) [emulation] - gamegear emulation - sg-1000 emulation - emulating additional cart work ram (Ernie Els Golf, the castle, Othello) - emulating bus contention - emulating game gear bios - emulating custom sram sizes (Shining force) - emulating eeprom of the baseball series games - emulating lightpahser, paddle (japanese and export), sportspad (japanese and export), 3d glasses, Terebi Oekaki - emulating gear-2-gear at cycle level - parallel communication (Squinky Tennis in micro machines, Primal Rage, ...) - serial communication - different baud rate settings - emulating backward compatibillity of gamegear(mastergear) and sms - emulating yamaha2413 - fex(zip, 7z, rar, gzip), bzip2, untar for compressed roms https://sourceforge.net/projects/twombit/ [bugfixes] - removed cache for irq detection, now irqs will be detected one cpu cycle before opcode edge ( simplified the overall process) - fixed sample playback - differentiate between sg and sms/gg vdp delay and access window behavior. to do: feature doings - cheats - savestates - replace directx to make TwoMbit platform independant accuracy doings - sn76489: writing to regs will not processed without delay - vdp: accurate access windows during sprite processing - vdp: split sprite subprocessing in timed steps (like bg processing) and not one sprite at a time - yamaha2413: sub sample accuracy

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