Re: PC speaker, Adlib, MIDI, Sound source volume using 16-bit samples(with dB scale 0-1 for setting the volume)?

Posted on 2015-12-01, 06:09

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by superfury

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With 48dB being full attenuation (so it's a linear factor of 1.0. So the linear curve of the value set by the register (0-48dB) is mapped to a workable multiply factor (0.0-1.0) to multiply the output samples with for the correct volume). So effectively output of a sample is: ChannelOutput = …

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Re: PC speaker, Adlib, MIDI, Sound source volume using 16-bit samples(with dB scale 0-1 for setting the volume)?

Posted on 2015-11-30, 21:16

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by superfury

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Well, the only place the value of 100 is used, is when converting the soundfont sustain volume(in centibels) to a linear factor to sustain. All other calculations use value of 1(to convert volume linear 0-1 to a decibel-like curve with the same range and of course to calculate the linear 100%(output …

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Re: PC speaker, Adlib, MIDI, Sound source volume using 16-bit samples(with dB scale 0-1 for setting the volume)?

Posted on 2015-11-29, 23:06

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by superfury

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#define dB2factor(dB, fMaxLevelDB) pow(10, (((dB) - (fMaxLevelDB)) / 20)) #define factor2dB(factor, fMaxLevelDB) ((fMaxLevelDB) + (20 * log(factor))) dB2factor is used in generating volume envelopes and setting mixer volume(with fMaxLevelDB set to 1) for each emulated hardware stream(s) (3 pc …

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Re: 80(1)86 CPU with 6-byte prefetch buffer crashes Castlevania (MS-DOS 5.0)?

Posted on 2015-11-29, 14:39

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by superfury

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It seems to go wrong as well. I've added support for setting the 8-bit bus in the BIOS settings (effectively changing the Prefetch Input Queue for 80(1)86 processors to their 80(1)88 equivalents: 4 bytes prefetched instead of 6 bytes). When debugging the executed code using the emulator's own …

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PC speaker, Adlib, MIDI, Sound source volume using 16-bit samples(with dB scale 0-1 for setting the volume)?

Posted on 2015-11-28, 21:58

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by superfury

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Anyone knows what the correct 'volume' maximum values are for PC speaker, adlib, MIDI and Sound source? My application uses 16-bit samples atm. The PC speaker, adlib and Sound source range is currently set to generate values (sinus and derratives) in the range of -32768 to 32767. This applies to all …

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80(1)86 CPU with 6&4-byte prefetch buffer crashes Castlevania (MS-DOS 5.0)?

Posted on 2015-11-28, 15:26

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by superfury

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I've built a Prefetch Input Queue (6-byte in case of 8086 and 80186 processor emulation) into my CPU emulation: https://bitbucket.org/superfury/x86emu/src/3edad4c62e974d39fe46c691a02f35ebeaed0cab/cpu/cpu.c?at=master CPU_readOP reads byte from the prefetch buffer and reloads it if it's empty during …

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Re: x86EMU vs 8088MPH MOD playback using PC speaker?

Posted on 2015-11-23, 16:56

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by superfury

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Do you know how to make my PC speaker emulation so that (assuming software samples at the correct speed, like using the PIT0 for timing), playback by software gives the correct PCM output? Edit: I've tried running the current version (build 2015/11/23 8:53) on my Intel i7@4.0GHz. The CPU doesn't run …

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Re: x86EMU vs 8088MPH

Posted on 2015-11-23, 09:58

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by superfury

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I've just tested the new PC speaker emulation against 8088 MPH. The music seems fine for the most part (except some CPU heavy parts at which the sound changes very slow). It seems the FIFO buffer emulation slows the CPU emulation down to becoming very slow (running at about 0.2-0.3MIPS, integer …

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Re: x86EMU 4-color CGA mode fails retrieving graphics pixels completely?

Posted on 2015-11-22, 20:18

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by superfury

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I've moved PC Speaker buffering to the CPU thread(tickSpeakers function). Somehow I hear nasty pops in the sound? Anyone knows why? https://bitbucket.org/superfury/x86emu/src/dd … ker.c?at=master

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Re: x86EMU 4-color CGA mode fails retrieving graphics pixels completely?

Posted on 2015-11-21, 20:22

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by superfury

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I don't have real hardware to test it with, unfortunately. I've implemented the FIFO buffer in my latest build. CPU_readOP now tries to read from the FIFO if possible(fully filled for every instruction executed). When the FIFO is empty, the FIFO EIP to be read next instruction is updated with the …

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Re: x86EMU emulator releases

Posted on 2015-11-21, 19:56

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by superfury

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I'll test those changes later. My latest x86EMU build: x86EMU_20151121_1846.zip - Fixed PS/2 mouse missing IRQ handling. - Implemented prefetching for all CPUs. Edit: I've tried your instructions. It now installs correctly (I didn't closed the window when it told me to during installation). I've …

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Re: VGA VRAM read/write multithread locking required?

Posted on 2015-11-20, 12:51

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by superfury

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Emulated VRAM doesn't have locks. The main thread reads and writes to emulated VRAM. The rendering thread only reads from emulated VRAM. Any VGA register changes (resolution changes and other settings of the VGA) are protected with locks when updating the renderer information from the CPU thread( …

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Re: x86EMU emulator releases

Posted on 2015-11-20, 12:39

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by superfury

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I get some errors running the SDL-install: Unpacking "SDL-1.2.15.zip" into "C:\MinGW\src". 'sh' is not recognized as an internal or external command, operable program or batch file. 'sh' is not recognized as an internal or external command, operable program or batch file. 'sh' is not recognized as …

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VGA VRAM read/write multithread locking required?

Posted on 2015-11-18, 00:52

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by superfury

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I have the main thread(CPU emulation) writing and reading emulated VGA vram memory. There's also a timer thread reading that memory and writing it to the emulator display buffer. Will CPU emulation reads/writes produce errors reading/writing the emulated VRAM? Or will only the renderer produce …

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Re: x86EMU emulator releases

Posted on 2015-11-18, 00:32

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by superfury

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I also try to get MinGW set up and running, but it won't work installing according to the basic manual, then compiling SDL 1.X (Latest version as far as I can remember). It gives me a lot of compile errors about stuff not being found etc. After that I still need to compile SDL_gfx and then my own …

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Re: x86EMU emulator releases

Posted on 2015-11-17, 16:04

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by superfury

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You need the Visual C++ 2015(community) runtime redistributable in order to run it.

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Re: x86EMU 4-color CGA mode fails retrieving graphics pixels completely?

Posted on 2015-11-16, 16:29

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by superfury

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What about MMI/O, like VGA VRAM? When the prefetch reads VRAM which is protected(but protection is ignored or simply too far past the code to be executed), it might cause the VGA memory latches to be loaded when actually they shouldn't? Like REP STOSW; RET just before VRAM, at address 9000:FFFD ( …

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Re: x86EMU 4-color CGA mode fails retrieving graphics pixels completely?

Posted on 2015-11-16, 15:41

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by superfury

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If I call MMU_rb for any illegal segment:offset(it executes both paging and segment protection emulation as well as read the data from emulated memory) from the prefetch buffer filling routine, it will always raise exceptions after 16 bytes before the end of the code segment: IP+prefetchsize>=CS. …

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Re: x86EMU 4-color CGA mode fails retrieving graphics pixels completely?

Posted on 2015-11-16, 14:56

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by superfury

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The problem is that if I remove the call to MMU_rb(which is also used during normal memory accesses by the CPU) and replace it with a direct memory approach (needing a complete copy of the entire memory module, the CPU emulation won't have ANY protection left anymore. No exceptions will be triggered …

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Re: x86EMU 4-color CGA mode fails retrieving graphics pixels completely?

Posted on 2015-11-16, 13:14

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by superfury

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When 16 bytes of memory data are prefetched in protected mode and I read the prefetch buffer from memory with less than 16 bytes left in the code segment it will raise an exception, even when less than 16 bytes are actually executed (since it will try to read past the end of the code segment, …

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