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Note that "powerpc" is the 32-bit PowerPC, if I'm not mistaken. ppc64el (64-bit little-endian PowerPC) is listed as a release architecture.
by pdw 10y ago
Note that "powerpc" is the 32-bit PowerPC, if I'm not mistaken.
ppc64el (64-bit little-endian PowerPC) is listed as a release architecture.
- bri3d 10y agoppc64el isn't supported on legacy Motorola PowerPC CPUs or IBM POWER7 or lower, so a large swath of 64-bit PowerPC is also unsupported (POWER7, G5, etc.): https://wiki.debian.org/ppc64el https://wiki.debian.org/ppc64el For comparison, Ubuntu discontinued official support for this platform in 2007 (!), although an "unofficial" community port lives on.
- bandrami 10y agoThe port covered both 32 and 64 bit chips. The specific 64 bit little endian support (ie, your old iBook) was broken out into the ppc64el in either Squeeze or Jessie.
- arcticbull 10y agoApple PPC[64] devices were all big endian. Little-endian mode (ppc64le) was introduced on POWER8 circa 2013.
- bandrami 10y agoThe chip itself is ambidextrous or whatever the word is.
- klodolph 10y agoWell, sort of. First of all, the 970 (aka G5) doesn't support little-endian. Second of all, you need board-level support, since the chip only does half of the work.
- andreiw 10y agoThe board-level (chipset) thing hasn't been true since "true" LE support was introduced. So Power8 machines can switch arbitrarily between endianness by changing MSR.LE. In fact, you could even run exception vectors at a different endianness from other code (MSR.ILE != MSR.LE), and endianness doesn't need to match between a hypervisor and VM.
- klodolph 10y agoYeah, that's right—I should have clarified that I was talking about pre-970 chips. But we're talking about older Apple laptops here.
- filereaper 10y agobi-endian ;)
- arcticbull 10y agoIt depends on what you mean; the PowerPC 970 (G5) did not support little endian mode at all. Earlier PowerPC devices (dating back to the PowerPC 601 IIRC) do in fact support runtime switching of endianness, although they were all 32-bit. PowerPC 64 LE is only supported on POWER8 (and apparently, per other commenters, requires hardware support although as a Mac developer I stopped paying attention after the 970 for some reason :) I think it's probably fair to say all the Apple devices that shipped were big endian as the OS and firmware were, and while in theory the 32-bit machines could operate in little-endian mode I don't know of any distributions that actually did so, and 970 didn't support it.
- mrpippy 10y agoVirtual PC on the Mac did use the pseudo-little-endian instructions/mode when emulating x86, this made a lot of work for Microsoft when the 970 came out without pseudo-little-endian.
- tropo 10y agoMatrox (yes, the graphics card company) sold a PCI board with several PowerPC "G4" chips that ran little-endian Linux. They posted a smallish kernel patch for this. MC/OS and Windows NT 4.0 also ran little-endian on PowerPC. The hardware support was simple: swap all 8 byte lanes for every memory access. It only mattered when MMIO or DMA was involved, so a software-only alternative was to have the OS do that -- but disk access via DMA would make the software solution impractical.