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Hi! |
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On Thu, 29 Jun 2017, James Le Cuirot wrote: |
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> > No. Alpha is little endian. |
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> |
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> Wikipedia says it is bi. tc-native() reports alpha* as big so I guess |
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> that's the only variant we support? Then again, this page says it is |
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> usually little. Is tc-native() wrong? |
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> |
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> https://kernelnewbies.org/EndianIssues |
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For the purposes of explanation, let's distinguish |
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Alpha-the-processor from Alpha-the-systems here. |
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Yes, the AtP can be switched between big- and little-endianess. |
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AtS can't. That is, once built, hardware-wise, it has to be |
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either, but can never switch. Even the firmware has to be |
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different between LE and BE systems. |
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There are a lot of LE Alpha systems, in essence, everything that |
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was ever sold as an Alpha system by DEC, Compaq, HP and sundry |
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others (like Samsung, who made the UP1500 and related systems). |
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As a guideline: if it ever ran True64, OSF/1 or digital alpha |
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UNIX, it is little-endian. |
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The machines that run Alpha CPUs in big-endian mode are |
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exclusively Cray supercomputers like the Cray T3D and T3E series. |
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Linux only ever supported parts of the former group (e.g. the |
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high-end Alpha server GS1280 series from Compaq is definitely not, |
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despite running in little-endian mode). The big endian Crays were |
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never even close to be supported. |
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tl;dr: Alpha is little-endian only for (our) practical purposes. |
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Regards, |
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Tobias |
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PS: There may be obscure one-off or developer boards for Alphas |
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which can switch, but the tl;dr still stands. |
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-- |
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Sent from aboard the Culture ship |
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GSV (Range Class) Ethics Gradient |
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