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IBM also for years screamed at devs that you can't rely on a PPC system being BE. Which means all oldworld MacOS software was at least theoretically written by
by bandrami 12y ago
IBM also for years screamed at devs that you can't rely on a PPC system being BE. Which means all oldworld MacOS software was at least theoretically written by people who couldn't tell you what byte order they were writing for. (How seriously the devs took that admonition is a different question.)
- vonmoltke 12y agoI was writing real-time signal processing software for POWER as recently as three years ago. I'm not even aware that was IBM's position, and they were our partners on the venture. That said, it really didn't matter because all our software had to build and run on x86-64 anyway, so all the endian-specific code was wrapped in preprocessor directives. We could have changed the endianness with a single makefile change.
- bandrami 12y agoI'm not even aware that was IBM's position Yeah, I said it badly. IBM wouldn't guarantee Apple that Power would always support BE, so Apple pushed (or tried to) developers not to assume that.
- vonmoltke 12y agoThat makes sense. IBM knew we were focused on the POWER7 blades and that our backup plan was their Intel blades, so they probably figured the warning wouldn't be relevant to us.
- duskwuff 12y agoThe PowerPC architecture was bi-endian, but classic Mac OS was very definitely big-endian. The only situation where the CPU would switch to little-endian would be if it was running Virtual PC. (And even then, it'd switch back for other applications.)
- bandrami 12y agoSorry, yeah, I stated that badly: Apple kept screaming at devs that IBM couldn't be guaranteed to keep the arch bi-endian, so Apple couldn't guarantee a big-endian platform and developers shouldn't assume one.