07-10-2009, 11:24 PM
12-08-2009, 12:42 AM
I know this thread is a bit old but I figured I might put in my 2¢.
(Butchered for simplicity over accuracy
64 bit has two advantages: 1) Larger number. The max size of a 32 bit number is approx 2^32 and the max size of 64 bit is 2^64. 2) More registers. These are basically memory variables directly in the CPU for extremely fast access. This way the program does not have to read everything from RAM (cache tech) during every line of code.
In other words, if your program does not need numbers that are super long in size then 64 bit computing has no benefit. This is why most software today is 32 bit.
However, when making an emulator you're copying the hardware, not a specific piece of software. If the hardware you are emulating has 64 bit support then coding your emulator in 64 makes sense. It is much slower to make a program run 64 length numbers on a 32 bit system... much much slower. However, it is not impossible. A hassle is the best way to describe it.
So lets say you're emulating the SNES. It is not a 64 bit device so making a 64 bit emulator will most likely have no speed up at all (unless you needed more registers for a specific reason). However, when emulating a powerPC cpu like what is in the gamecube and the wii 64 bit will significantly speed up the emulation. Not only is it a 64 bit cpu but PPC generally has more registers so 64 bit can help in that sense too.
The only reason you're not seeing a 2x to 4x speed increase from the 64 bit version of dolphin is that most of the games take little to no advantage of the 64 bit support on the hardware just like most software on your computer today does not take advantage of the 64 bit support either. This means that the speedup can vary a great deal from game to game, but because of the register increase there should always be a speedup in 64 bit mode even if it is only a slight speedup.
In a way the concept is the same for multi core systems. Since the gamecube and wii are single core you will not get an advantage from having a multi core cpu (with the exception of a second core to offload the system and other software running in the background) but for systems like the xbox360, ps3, saturn, ... that are multi core you take a large hit if you do not have the number of cores as the hardware you are emulating.
Hopefully this comment will help you guys understand why 64 bit is beneficial when it comes to emulation even if my examples are a bit simplistic and lack accuracy.
(Butchered for simplicity over accuracy
64 bit has two advantages: 1) Larger number. The max size of a 32 bit number is approx 2^32 and the max size of 64 bit is 2^64. 2) More registers. These are basically memory variables directly in the CPU for extremely fast access. This way the program does not have to read everything from RAM (cache tech) during every line of code.
In other words, if your program does not need numbers that are super long in size then 64 bit computing has no benefit. This is why most software today is 32 bit.
However, when making an emulator you're copying the hardware, not a specific piece of software. If the hardware you are emulating has 64 bit support then coding your emulator in 64 makes sense. It is much slower to make a program run 64 length numbers on a 32 bit system... much much slower. However, it is not impossible. A hassle is the best way to describe it.
So lets say you're emulating the SNES. It is not a 64 bit device so making a 64 bit emulator will most likely have no speed up at all (unless you needed more registers for a specific reason). However, when emulating a powerPC cpu like what is in the gamecube and the wii 64 bit will significantly speed up the emulation. Not only is it a 64 bit cpu but PPC generally has more registers so 64 bit can help in that sense too.
The only reason you're not seeing a 2x to 4x speed increase from the 64 bit version of dolphin is that most of the games take little to no advantage of the 64 bit support on the hardware just like most software on your computer today does not take advantage of the 64 bit support either. This means that the speedup can vary a great deal from game to game, but because of the register increase there should always be a speedup in 64 bit mode even if it is only a slight speedup.
In a way the concept is the same for multi core systems. Since the gamecube and wii are single core you will not get an advantage from having a multi core cpu (with the exception of a second core to offload the system and other software running in the background) but for systems like the xbox360, ps3, saturn, ... that are multi core you take a large hit if you do not have the number of cores as the hardware you are emulating.
Hopefully this comment will help you guys understand why 64 bit is beneficial when it comes to emulation even if my examples are a bit simplistic and lack accuracy.
12-08-2009, 03:06 AM
hey...you made it sound even understandable for me...that's pretty impressive 
12-08-2009, 03:10 AM
12-08-2009, 03:15 AM
r4652x64 is stable for me
12-08-2009, 06:12 AM