Dolphin Emulator - Dolphin MEGA Progress Report: April and May 2021 • Hacker News Board

>This was thankfully a lot less strict than on iOS devices, which strictly forbid mapping memory as executable whatsoever and made iOS untenable for us to officially support. Apple even provides documentation for helping developers port JITs to macOS on ARM. Skyler used a method described in the documentation that would change the mapped memory between Writeable when emitting code to Executable when executing code. Since Dolphin wasn't designed for this, there were a few hiccups along the way, but eventually everything was massaged into working with the new restrictions.

How expensive is changing memory mapping modes? Does it involve a system call? Does it need to happen often?

Re: Dolphin Emulator - Dolphin MEGA Progress Report: April and May 2021

#7

Post by flatiron » Sun, Jun 06, 2021, 1:49 PM UTC

kzrdude wrote: post #2

How well does dolphin run on Rpi 4 now?

Look for a second hand Wii U. Plays GC wii and Wii U games with hdmi!

Re: Dolphin Emulator - Dolphin MEGA Progress Report: April and May 2021

#8

Post by masklinn » Sun, Jun 06, 2021, 1:56 PM UTC

DonHopkins wrote: post #6

>This was thankfully a lot less strict than on iOS devices, which strictly forbid mapping memory as executable whatsoever and made iOS untenable for us to officially support. Apple even provides documentation for helping developers port JITs to macOS on ARM. Skyler used a method described in the documentation that would change the mapped memory between Writeable when emitting code to Executable when executing code. S…

No / yes / only once.

It's just an mprotect(2) call to change the page from R+W to R+X. It needs to happen between the JIT being done creating a hunk of code and the first execution. Basically: allocate a page, write generated machine code to the page, change page to executable, patch page in (so the code gets invoked instead of either interpretation or a baseline compiler).

I'm sure you can be smarter about it and involve locks such that you track how full "code pages" are and switch non-full pages back to writeable in order to update their content.

Re: Dolphin Emulator - Dolphin MEGA Progress Report: April and May 2021

#9

Post by bennysomething » Sun, Jun 06, 2021, 2:04 PM UTC

flatiron wrote: post #7

kzrdude wrote: post #2

How well does dolphin run on Rpi 4 now?

Look for a second hand Wii U. Plays GC wii and Wii U games with hdmi!

Does it upscale GameCube games? If not do the still look ok? Dreamcast VGA 480p still looks great.

Re: Dolphin Emulator - Dolphin MEGA Progress Report: April and May 2021

#10

Post by umvi » Sun, Jun 06, 2021, 2:05 PM UTC

I recently wanted to play the original Paper Mario, but sadly it's not available on Switch, only Wii U. So I decided to go the emulator route. Dolphin is so good that Paper Mario runs better as a Wii U Virtual Console ROM under Dolphin than it does as an N64 ROM under Project 64.