bsnes/higan/pce/cpu/memory.cpp

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Update to v102r04 release. byuu says: Changelog: - Super Game Boy support is functional once again - new GameBoy::SuperGameBoyInterface class - system.(dmg,cgb,sgb) is now Model::(Super)GameBoy(Color) ala the PC Engine - merged WonderSwanInterface, WonderSwanColorInterface shared functions to WonderSwan::Interface - merged GameBoyInterface, GameBoyColorInterface shared functions to GameBoy::Interface - Interface::unload() now calls Interface::save() for Master System, Game Gear, Mega Drive, PC Engine, SuperGrafx - PCE: emulated PCE-CD backup RAM; stored per-game as save.ram (2KiB file) - this means you can now save your progress in games like Neutopia - the PCE-CD I/O registers like BRAM write protect are not emulated yet - PCE: IRQ sources now hold the IRQ line state, instead of the CPU holding it - this fixes most SuperGrafx games, which were fighting over the VDC IRQ line previously - PCE: CPU I/O $14xx should return the pending IRQ bits even if IRQs are disabled - PCE: VCE and the VDCs now synchronize to each other; fixes pixel widths in all games - PCE: greatly increased the accuracy of the VPC priority selection code (windows may be buggy still) - HuC6280: PLA, PLX, PLY should set Z, N flags; fixes many game bugs [Jonas Quinn] The big thing I wanted to do was enslave the VDC(s) to the VCE. But unfortunately, I forgot about the asynchronous DMA channels that each VDC supports, so this isn't going to be possible I'm afraid. In the most demanding case, Daimakaimura in-game, we're looking at 85fps on my Xeon E3 1276v3. So ... not great, and we don't even have sound connected yet. We are going to have to profile and optimize this code once sound emulation and save states are in. Basically, think of it like this: the VCE, VDC0, and VDC1 all have the same overhead, scheduling wise (which is the bulk of the performance loss) as the dot-renderer for the SNES core. So it's like there's three bsnes-accuracy PPU threads running just for video. ----- Oh, just a fair warning ... the hooks for the SGB are a work in progress. If anyone is working on higan or a fork and want to do something similar to it, don't use it as a template, at least not yet. Right now, higan looks like this: - Emulator::Video handles the platform→videoRefresh calls - Emulator::Audio handles the platform→audioSample calls - each core hard-codes the platform→inputPoll, inputRumble calls - each core hard-codes calls to path, open, load to process files - dipSettings and notify are specialty hacks, neither are even hooked up right now to anything With the SGB, it's an emulation core inside an emulation core, so ideally you want to hook all of those functions. Emulator::Video and Emulator::Audio aren't really abstractions over that, as the GB core calls them and we have to special case not calling them in SGB mode. The path, open, load can be implemented without hooks, thanks to the UI only using one instance of Emulator::Platform for all cores. All we have to do is override the folder path ID for the "Game Boy.sys" folder, so that it picks "Super Game Boy.sfc/" and loads its boot ROM instead. That's just a simple argument to GameBoy::System::load() and we're done. dipSettings, notify and inputRumble don't matter. But we do also have to hook inputPoll as well. The nice idea would be for SuperFamicom::ICD2 to inherit from Emulator::Platform and provide the desired functions that we need to overload. After that, we'd just need the GB core to keep an abstraction over the global Emulator::platform\* handle, to select between the UI version and the SFC::ICD2 version. However ... that doesn't work because of Emulator::Video and Emulator::Audio. They would also have to gain an abstraction over Emulator::platform\*, and even worse ... you'd have to constantly swap between the two so that the SFC core uses the UI, and the GB core uses the ICD2. And so, for right now, I'm checking Model::SuperGameBoy() -> bool everywhere, and choosing between the UI and ICD2 targets that way. And as such, the ICD2 doesn't really need Emulator::Platform inheritance, although it certainly could do that and just use the functions it needs. But the SGB is even weirder, because we need additional new signals beyond just Emulator::Platform, like joypWrite(), etc. I'd also like to work on the Emulator::Stream for the SGB core. I don't see why we can't have the GB core create its own stream, and let the ICD2 just use that instead. We just have to be careful about the ICD2's CPU soft reset function, to make sure the GB core's Stream object remains valid. What I think that needs is a way to release an Emulator::Stream individually, rather than calling Emulator::Audio::reset() to do it. They are shared\_pointer objects, so I think if I added a destructor function to remove it from Emulator::Audio::streams, then that should work.
2017-01-26 01:06:06 +00:00
//PC Engine HuCards lack save RAM on them due to the card size and cost savings.
//The PC Engine CD adds 2KB of backup RAM that most HuCard games can use for saves.
//However, all games must share this small amount of RAM.
//Since this is an emulator, we can make this process nicer by storing BRAM per-game.
//This does hard-code the save.ram name, rather than using a manifest file name.
//It also creates a save.ram file no matter what, even for games that don't save data.
//Unfortunately, we can't know in advance if a game supports BRAM saves or not.
//So because of this, we have to always create it.
//Thankfully, the file is very small so it should not prove to be a burden in practice.
auto CPU::load() -> void {
for(auto& byte : bram) byte = 0xff;
if(auto fp = platform->open(cartridge.pathID(), "save.ram", File::Read)) {
fp->read(bram, 0x800);
}
}
auto CPU::save() -> void {
if(auto fp = platform->open(cartridge.pathID(), "save.ram", File::Write)) {
fp->write(bram, 0x800);
}
}