amd64 and n64 emulation

duke · August 17th, 2003

Since the N64 has a 64bit cpu .. right ? When it has to do 64bit math calculations these are gonna take a lot longer on a 32bit CPU to calculate, im guessing twice or 4 times as long. How much do u people think a 64bit compiled version for AMD 64 would speed up emulation for the n64 ?

Andrew Hruska · August 17th, 2003

Well, you could probably ( with a 64-bit version, of, say, 1964 ) use higher things like 16xAA or higher resoulutions. No speed downs, and it would probably rock the N64 emulation community ( MAYBE ). Let's hope by x-mas we all can get the Athlon 64 and a good Geforce FX or ATI Radeon 9###

**Zephon** · August 20th, 2003

Quote:

Originally Posted by Andrew Hruska

Well, you could probably ( with a 64-bit version, of, say, 1964 ) use higher things like 16xAA or higher resoulutions. No speed downs, and it would probably rock the N64 emulation community ( MAYBE ). Let's hope by x-mas we all can get the Athlon 64 and a good Geforce FX or ATI Radeon 9###

Unlikely. FSAA and high resolutions are very dependent on the video card, so getting a more powerful cpu will not help.

Well, getting Athlon64 probably would speed up things somehow, but that's about it. Besides, I don't think any emu author has plans to release a 64bit version of his emulator. It would require a re-write of most of the code, and also the user (as well as the programmer) would have to have this 64bit cpu, as well as a 64bit OS. As not everybody has conditions to simply buy a new computer, it probably will take time until it gets popular (specially since Intel does not have a similar product to be released soon).

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Alias · August 25th, 2003

the code probably doesn't have to be altered much, but it will cetainly have to be recompiled under a 64-bit OS.

Don't make the mistake of just matching the n64's "64-bit" to the athlon's "64." Today's 32-bit cpus are more than overkill for n64 emulation. It's true that the n64 has a "64-bit" processor, but this only measures integer performance. It's floating point performance is no doubt eclipsed by even a pentium III (mebbe pentium II even). And though today's cpu's can only handles 32-bits of integer information at once, they have several integer registers (much like pipelines) that run in parallel which equal much more than n64's processor could ever hope to attain. Processors are much more complicated that the marketing 32/64-bit monkier that they're paired with.

Ask in the hardware forums (where Demigod and Exophase would be able to explain much more on the topic).

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Exophase · August 26th, 2003

I haven't studied the N64's CPU much at all (R4100i I believe) but I believe many instructions have both 32bit and 64bit forms. Usually the 32bit form would be used, since 64bit integer math is rarely helpful. However, in cases where 64bit math is required, not only will it cause more work for the 32bit CPU to perform the operation but it will have to sacrifice another of the x86's (already limited) 32bit registers for reg caching of the upper part of the 64bit MIPS register. So, if anything, Athlon 64 would at least be able to provide full 64bit regcaching, and moreover it'd be able to provide twice as many registers (16 instead of 8) putting less strain on the reg caching, since R4100 has 32 registers. Unfortunately for this to happen much more than a recompile would be necessary; the dynarec core of the emulator would have to be revised. For non-dynarec there would only be a slight performance increase (gained from compiling with the extra registers enabled).

- Exo

duke · August 28th, 2003

I think thats a pretty good answer. Seeing as to do something like a 64 bit add you are going to need perhaps 4 registers. 2 to hold the 1st 64bit number and another 2 to stick the result in, well in arm assembly anyway. I dunno enough about x86 but i guess it will be similar. I guess depending on how much 64bit code there is and how many 64bit arithmetic caculations n64 games actually actually require will depend on much much speed increase a recompilation/optimisation for the amd64 could yield :P

ready2rumbelX · March 23rd, 2004

Reading this makes me feel better....cause the AMD64 is so damn expensive!

r2rX

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**Kane** · March 24th, 2004

...This is a decidedly old thread. Please don't ressurect it for no real reason.

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August 17th, 2003	#1 (permalink)
duke Registered User Join Date: Jul 2003 Location: UK Posts: 101	amd64 and n64 emulation Since the N64 has a 64bit cpu .. right ? When it has to do 64bit math calculations these are gonna take a lot longer on a 32bit CPU to calculate, im guessing twice or 4 times as long. How much do u people think a 64bit compiled version for AMD 64 would speed up emulation for the n64 ?

August 26th, 2003	#5 (permalink)
Exophase Emu author Join Date: Apr 2001 Location: Bloomington IN, USA Posts: 1,061	Re: amd64 and n64 emulation I haven't studied the N64's CPU much at all (R4100i I believe) but I believe many instructions have both 32bit and 64bit forms. Usually the 32bit form would be used, since 64bit integer math is rarely helpful. However, in cases where 64bit math is required, not only will it cause more work for the 32bit CPU to perform the operation but it will have to sacrifice another of the x86's (already limited) 32bit registers for reg caching of the upper part of the 64bit MIPS register. So, if anything, Athlon 64 would at least be able to provide full 64bit regcaching, and moreover it'd be able to provide twice as many registers (16 instead of 8) putting less strain on the reg caching, since R4100 has 32 registers. Unfortunately for this to happen much more than a recompile would be necessary; the dynarec core of the emulator would have to be revised. For non-dynarec there would only be a slight performance increase (gained from compiling with the extra registers enabled). - Exo

August 28th, 2003	#6 (permalink)
duke Registered User Join Date: Jul 2003 Location: UK Posts: 101	Re: amd64 and n64 emulation I think thats a pretty good answer. Seeing as to do something like a 64 bit add you are going to need perhaps 4 registers. 2 to hold the 1st 64bit number and another 2 to stick the result in, well in arm assembly anyway. I dunno enough about x86 but i guess it will be similar. I guess depending on how much 64bit code there is and how many 64bit arithmetic caculations n64 games actually actually require will depend on much much speed increase a recompilation/optimisation for the amd64 could yield :P

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August 17th, 2003	#2 (permalink)
Andrew Hruska Banned Join Date: Mar 2003 Location: somewhere Posts: 1,121	Well, you could probably ( with a 64-bit version, of, say, 1964 ) use higher things like 16xAA or higher resoulutions. No speed downs, and it would probably rock the N64 emulation community ( MAYBE ). Let's hope by x-mas we all can get the Athlon 64 and a good Geforce FX or ATI Radeon 9###

August 25th, 2003	#4 (permalink)
Alias >_< Join Date: Jun 2002 Location: East Coast, USA Posts: 924	the code probably doesn't have to be altered much, but it will cetainly have to be recompiled under a 64-bit OS. Don't make the mistake of just matching the n64's "64-bit" to the athlon's "64." Today's 32-bit cpus are more than overkill for n64 emulation. It's true that the n64 has a "64-bit" processor, but this only measures integer performance. It's floating point performance is no doubt eclipsed by even a pentium III (mebbe pentium II even). And though today's cpu's can only handles 32-bits of integer information at once, they have several integer registers (much like pipelines) that run in parallel which equal much more than n64's processor could ever hope to attain. Processors are much more complicated that the marketing 32/64-bit monkier that they're paired with. Ask in the hardware forums (where Demigod and Exophase would be able to explain much more on the topic). __________________ >_<

March 23rd, 2004	#7 (permalink)
ready2rumbelX InnarX Join Date: Jul 2002 Location: Borderline InSAnE Posts: 2,689	Reading this makes me feel better....cause the AMD64 is so damn expensive! r2rX __________________ ready2rumbelX -Intel Core 2 Quad Q6600 (@3200Mhz) -Gigabyte 965P-S3 motherboard -2x2GB G.Skill PC-6400 (DDR2 800Mhz) RAM (4-4-4-12) -Seagate 320GB (IDE) and Western Digital 500GB (SATA II) H.D -Sapphire Radeon HD 4870 512MB GDDR 5 (850/4600) -Windows Vista Ultimate SP1 (x64) -Realtek HD w/ Creative PC Works 5.1 -2 x L.G DVD/CD-RW Combo - GSA-H62N

March 24th, 2004	#8 (permalink)
Kane 邪魔ゎ指せない Join Date: Jan 2002 Location: Gosport, England Posts: 26,305	...This is a decidedly old thread. Please don't ressurect it for no real reason. __________________ >Site Live< Pop over to my site for help with setting up PSX emulators. Help for the Final Fantasies and other RPGs avalaible Celes: (Desktop) Athlon 64 X2 4200+, 2Gb 400MHz DDR Ram, MSI K8N Platinum, GeForce 8800 GTS 320Mb, 500Gb RAID HDD, Vista Business Erika: (MCPC) Athlon XP 2400+, 1Gb 400MHz DDR Ram, geForce 6800 256Mb, 80Gb Hdd, XP 2005 MCE Kimiko: (Desktop 2) Athlon 64 3000+, 512Mb 400MHz DDR Ram, Asus K8V, geForce 6800 128Mb