I'm trying to go off memory of a few things so bear with me here. Strange thing is that PowerPC® Microprocessor Family: The Programmer’s Reference Guide from 1995 (from PowerPC 60x age) at page 20 shows 32-bit and 64-bit BAT registers. Good think that manual also says, when talking about BAT:s and memorymanagement: "However, if these features are not supported, attempting to execute these instructions on a 64-bit implementation causes an illegal instruction program exception." so you can catch that and make emulation. "The bridge features do not conceal the differences in format of the page table, BAT registers, and SDR1 between 32-bit and 64-bit implementations-the operating system must be converted explicitly to use the 64-bit formats." Oh.it just read just before that I copy paste from PowerPC® Microprocessor Family: The Programming Environments Manual for 32 and 64-bit Microprocessors Of course there isn't drivers for motherboard components or is there in something usefull its 1 MB ROM or 3 MB toolbox ROM loaded into RAM? I talking about first G5s with AGP and PCI-X. It might be that G5 ROM-boot code start reading disks in 32-bit mode, so it might that bridge feature is default in start.īut I don't mean last G5s with PCIe. – If any 64-bit instructions are used for example,to modify a PTE or a 64-bi tSPR,en sure either that exceptions cannot occur or that the exception handler saves and restores all 64 bits of the GPRs.Īnd some things more, that is not problem. The operating system should do the following: The boot process should do the following: – ClearMSR. I have to check it.I made fast reading "PowerPC® Microprocessor Family:The Programming Environments Manual for 32 and 64-bit Microprocessors" and I found:Īn operating system that uses the bridge features does not take full advantage of the 64-bit implementation (for example, it can generate only 32-bit effective addresses).Īn operating system that uses the 64-bit bridge architecture should observe the following: There can be lot of difference and they can trapped with illegal instruction traps, but still it cannot be completely different type of instruction set. Actually that cannot be true, because then any of G3/G4 Mac OSX programs cannot work in G5 (or of course in emulation they can work).
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