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Where are the PPC Emulators?

Posted by Cliff on from the it-ain't-as-easy-as-you-think dept.

mikenetaim asks: "Numerous people have started projects aimed at emulating the PPC based Macintosh. Those that run on machines with a PPC tend to succeed (MacOnLinux, Sheepshaver, iFusion), and every single one which attempted to emulate the CPU failed. Everyone admits that an emulated CPU will run slowly, but no one has ever released a working PPC emulator at any speed (except for an incomplete one, whose name escapes me, that was released a long time ago to statically translate AIX binaries). There are a ton of 68k emulation code floating around the 'net, and a PPC emulator should be easier to produce (due to fixed instruction length, branch predication, opcodes that dictate if CCR flags must be generated, etc). Most of the authors just claim their project was harder than they expected before disappearing. Why do all these projects fail? Can anyone point me to any information or code?"

2 of 34 comments (clear)

  1. PPC vs x86 by Kisai · · Score: 2, Interesting

    Aparently the problem is that emulating an PPC on an x86 is an incredable headache. While emulating a x86 on a PPC is a piece of cake.

    Though in theory, not matter how embarassingly slow the emulator is, it should be possible to make one.

    In general you need a host processor 50 times faster, Mhz for Mhz than the one you want to emulate to get any decent performance on a first-generation emulator.

    Emulating a 68K Amiga or Mac (at like 8Mhz) only takes a 400Mhz processor to perform decently. A 100Mhz PPC would require a something like a 5Ghz Host processor to get about the same performance. Take into account all the other hardware while you are at it.

    Second generation emulators (Optimized, dynamic recompilation, all other buzz words, etc) require something in the rage of 10 times more powerful.

    No GameCube emulation till we are in double-diget Ghz processors, or someone gets the brilliant idea of not emulating the CPU/Graphics Hardware.

    1. Re:PPC vs x86 by Goose+In+Orbit · · Score: 2, Interesting
      Emulating a 68K Amiga or Mac (at like 8Mhz) only takes a 400Mhz processor to perform decently
      Full speed Atari ST emulation (68k @ 8MHz) has been possible for almost 10 years using "only" a 486/33 (or 486/50), so where does the 400MHz figure come from?

      Second generation emulators (Optimized, dynamic recompilation, all other buzz words, etc) require something in the rage of 10 times more powerful
      The later versions I have clocked at an equivalent of a 1GHz 68k on "only" a 1.2GHz Athlon.

      And yes, I know Darek can be an obnoxious little **** most of the time, and that his rep is even worse than Jim Drew as far as the Mac emulation community is concerned, but for my (simple) purposes Gemulator works fine, and you must admit he has pushed the boundaries like no-one else as far as I can tell (though I wouldn't mind being proved wrong)