I'm trying to make an extremely fast x86 emulator,as fast as ZSNES, NO$GMB, Nesticle, FCEU, Z26, etc.,I'm just starting but I made a simple unreal mode x86 corein 2024. I haven't find easy to use and easy to understandx86 CPU emulators. Can you give me tips on how to develop it faster? I'm proficientin normal low-level NASM/YASM for 16/32/64-bit, even portableacross them with the same code, or can you give me source codefor it, add code for me for free, not GNU licensed but justfree to use code, make code for this emulator or other system-levelcode for free? Here's what I'm done, this is like a game of making code for me,you are free to use/modify/relicense a copy of the code for yourself,it's just a game for me. Year 2024 Project - Studying Drivers In this year I was studying how to make and load Win9x drivers,ring 0 32-bit VxD, 16-bit DLL/DRV/SYS drivers. experimenting heavily withthe bit flags of those files' headers, realizing how these driverscan call BIOS interrupts and DPMI services. YouTube playlists:----------------------------- Example drivers and header configuration internals, built by hand with NASM(Pending, all information is still generic instead of in a single generator with all options manually selectable) Simple x86 CPU emulator manualhttps://www.youtube.com/watch?v=Jbuz-0mXGog&list=PLAtuuvZSlQWDlMZliuUKLvuJJOUvattDC
Miscellaneous driver informationhttps://www.youtube.com/watch?v=w3md8LIZui0&list=PLAtuuvZSlQWACwBI-LCfVOoZD_tdmtEMWhttps://www.youtube.com/watch?v=QZrqu5vu2wQ&list=PLAtuuvZSlQWCWnYfZsx0nZsDw81QjDlrphttps://www.youtube.com/watch?v=0hsr1qRJzq0&list=PLAtuuvZSlQWCA0vwxQu8tIcyn_HhwpB-lhttps://www.youtube.com/watch?v=V5l6R8_EXpY&list=PLAtuuvZSlQWAJNFuVeibXwB3itUY7ygWNhttps://www.youtube.com/watch?v=fHAmmnz6DtE&list=PLAtuuvZSlQWD2WHXXb1MsX4hhsOM7F1Gthttps://www.youtube.com/watch?v=Ms99-yd39_U&list=PLAtuuvZSlQWBJ6qpSKlGA3vNmjZ2zwkVPhttps://www.youtube.com/watch?v=vW6TjclARXA&list=PLAtuuvZSlQWDi_C4RTdFUPj4drq_VV3_X Source code:http://master.dl.sourceforge.net/project/api-simple-completa/apiclean.zip?viasf=1Clean code of the emulator kernel that aims to capture the execution of the native software/hardware http://master.dl.sourceforge.net/project/api-simple-completa/api.zip?viasf=1Full accumulated code I have seen that switching modes by hand is not so easy, My graphicsswitching code doesn't work if I first enter graphics mode with the BIOSand then I try to switch to another mode or to text mode with my code.It just doesn't work. This code, mainly the x86 CPU emulator and VxD/NE EXE driver file skeletonsin NASM, without needing the DDKs, special linkers, etc., is the code I wasworking on in 2024, most of the time. Short x86 CPU Emulator Manual------------------------------After adding the NASM code and selecting if it will compile for16, 32 or 64-bit with _x86_Portable__PLATFORMBITS_(with 1632, 32 or 64; pure 16-bit 8088 mode has not been tested), you have toconfigure the virtual CS:IP, DS, ES, FS, GS, SS and SP, so thatit can run some code: mov widedi,x86CPU push word 0x7C0 pop word[widedi+x86_CPU_State_SS] mov word[widedi+x86_CPU_State_SP],0x8000 push word[0x10*4+2] push word[0x10*4+2] push word[0x10*4+2] push word[0x10*4+2] push word[0x10*4+2] pop word[widedi+x86_CPU_State_CS] pop word[widedi+x86_CPU_State_DS] pop word[widedi+x86_CPU_State_ES] pop word[widedi+x86_CPU_State_FS] pop word[widedi+x86_CPU_State_GS] mov word[widedi+x86_CPU_State_CS],0mov word[widedi+x86_CPU_State_RIP],0 mov word[widedi+x86_CPU_State_AX],3h mov byte[widedi+x86_CPU_State_IPadd_state+1],1 Set the size of the virtual RAM, although it should be 0if you let the native hardware to validate the RAMaddress space and manage it properly from the emulated code: mov dword[widedi+x86_CPU_State_emuRAMSZ],1048576*4 ;Si es 0, es TODO el espaciomov dword[widedi+x86_CPU_State_emuRAM],0mov dword[widedi+x86_CPU_State_loopsPerTick],1 You have to mark the CPU state as running: mov byte[widedi+x86_CPU_State_IPadd_state+1],1 A test program: mov byte[0],0xCD mov byte[1],0x10 mov byte[2],0xFA mov byte[3],0xF4 The execution loop, with the initial cdecl parametercontaining a pointer to the virtual CPU structure: push widedi.lle: call OPCODE__emu86__C__CPU__emulate16 cmp byte[widedi+x86_CPU_State_IPadd_state+1],1je .lle Declare the virtual CPU structure: align 16x86CPU times x86_vrCPU_SZ db 0 To get the emulator kernel, a raw 32-bit binary by now:D:\apiclean\prg\emukern To get the loader for MS-DOS, that only loads 32-bit raw binaries by now:D:\apiclean\prg\kernels As you can see, the test kernel only enters mode 3h by nowwith the emulator and writes 2 colored bytes in the kernel loop.It runs at least in Bochs and maybe some old Thinkpad laptops.The emulator needs a lot of work to make it run as fast as thenative CPU, and adding full 16/32-bit protected mode, FPU,protection, emulated v86, paging, and later 64-bit long modefor being able to load and emulate the whole system, existingdrivers native to the machine where it is currently running,and full operating systems like DOS, Windows 3.0 (in 16-bitat least), Windows 9x, and older Linux, to make access tohardware that needs custom drivers possible. Completing this emulator in this fashion will take severalyears probably, along with learning to load drivers and theirexecutables of all kinds, but without that, fully understandingand taking advantage of the workings of the x86 PC ecosystemis just not possible with this way of developing a kernel,that in this case will be more brief, mostly only a CPU emulatorand key register/resources manager for ensuring it keeps full controlof the emulated state at all times. ---------------------------------------------------------------- In the full source code, in the VGA section, there are programsto save the palette and VGA registers, which can be used to debugwhich registers are well programmed and which not, after runninga VGA register programming sequence. Most of this emulator source code has been obtained with generatorsthat just copy the entire code to text or that dynamically generateeach part of the code, to ensure that the code is always fresh,as you always need to update the code or get another copy throughthe generators, so they will always be more up to date than the restof copies of the code. First I need to enumerate the things I need to achieve so farand that maybe someone else could help me with code. It takes metoo much to write very little code, and in a year I only manageto do the very basic of a project: - Make a full emulator (16/32/64-bit with full protection, paging, modern features, optimization to make it run as fast as the native CPU, capability to trace and extract the interesting parts of any program, driver, hardware sequences) that I can simply add to any program, with a port that commands the start of capturing any instructions in general or of a memory range, and a final instruction in a range, like ret or iret, that disables capturing instructions. - Build and load all sort of drivers (16/32-bit DLL/DRV, VxD, SYS, Linux, DOS, etc.) for all operating systems. In this way I can load them in my own kernel environment as if the hardware was fully standard/transparent. - Get the information to make all types of drivers, Win16/32/64, DOS, Linux, Mac, from the CDs that come with the hardware (video, audio, network, TV, USB, to load existing or custom drivers in any format). - Make a kernel that is capable to run a kernel containing an emulator capable of fully trapping the machine from real mode upwards through my own emulation so that everything becomes more reusable and fully understand everything that happens in each computer and how it works with the OS we will emulate along with the native hardware with the emulator (native hardware except what is necessary to trap the machine and fully emulated OS/software). I have been studying BIOS and Win9x drivers and making some simple ones by hand(16-bit DRV/DLL and 32-bit VxDs). I have also been making an Unreal Mode emulator for basic 16 and 32-bit instructions,to try to get to the point where I can load and run them from DOS for example.By now I can only run and extract things like video BIOS sequences (switching modes)and simple COM file running. Simple x86 emulator explanation:https://www.youtube.com/watch?v=ztw1AGmS20A&list=PLAtuuvZSlQWBdTfsKs4S790ZmxGm4SDLQ Full source code of the emulator and all my projects:http://master.dl.sourceforge.net/project/api-simple-completa/api.zip?viasf=1 My YouTube channel with programming playlists:https://www.youtube.com/@AltComp126/playlists Donate to PayPal or post more code if you want to help me:https://www.paypal.com/donate/?hosted_button_id=QEKQS2YTW3V64 If you want to help me more/daily, you can write me to udocproj...@yahoo.com---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- By now I will explain how the emulator can be added to a project. It is written in NASM, it is compatible with unreal mode, 32 and 64 bits(this last one is untested but it should compile). Having a full x86 emulator is a key milestone in addition to be able to runwith V86, VT-x, or other third party emulation sources. So far I have seen that it is easy to replicate drivers like diskio.dll,but other drivers like graphics, even Win9x VGA, have a much more unknown structurethat needs to be discovered for such a starting-level project with not much information. Declare in NASM: global _OPCODE__emu86__C__CPU__emulate16 >From the C code, just call OPCODE__emu86__C__CPU__emulate16(vrCPU); That will execute instructions one by one (normally, I will prepare it toexecute more than an instruction at a time for speed in the fullx86/x64/x87 emulator). The parameter it takes is a virtual CPU structure.You just need to configure CS:IP and other registers before starting.The CPU will not stop executing in a while loop until: while(*(unsigned char*)(vrCPU+x86_CPU_State_IPadd_state+1)==x86_CPU_status__running) You have this file to generate a stand-alone COM emulator for DOS or for 32/64-bitfor your own use: C:\api\CPU\x86\emu\NASM\x86emu16.asm__src.html It will generate x86emu16.asm. This is the unreal mode emulator, without anyprotected mode or protection, only basic unreal mode with 16/32-bit data. Here you have a demonstration of a DJGPP emulator, just run test.asm.You have main.asm, x86emu16.asm and main.c, and it will generate emu.exe: C:\api\PC\BIOS\emu\DJGPP You can run: tsrtest.comrmpmur.com -- just in case you run unreal mode codeemu.exe src.asm It will generate an .asm file, by now containing the in/out instruction sequencewith the values in EAX to reuse things like entering standard or VESA modes forany specific video card that you can later accomodate and run as native codeto manipulate the video on your own based exactly on what the emulator ran. VGA BIOS Drivers There is the vgaregs.c/vgaregs.exe program that extracts registers: vgaregs 3 mode3h.cvgaregs 13 mode13h.c myfile.c can be compiled into a program that switches into a standardVGA mode, with all of the registers you recorded when you entered thestandard mode with vgaregs.exe.
_______________________________________________ Freedos-devel mailing list Freedos-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-devel
