Not quite. When they switched to PowerPC, that was the case; the initial one was a table-driven instruction translator in ROM originally written for the M88k, which had been the original target before Motorola canned it, but it was apparently a relatively simple thing to change the translations to PowerPC instructions (only took a weekend according to legend, but, well, legends). It eventually evolved into something much more sophisticated and performant.
The transition from PowerPC to Intel ended the Classic VM environment that ran Mac OS 9, which included the old 68k translator in the ROM file. On a PowerPC Mac running OS X 10.4 (including G5s, which are 64-bit!), you can run 68k apps from the dark ages just fine (as long as they didn't use undocumented interfaces, etc). I've been doing exactly this recently while porting a very old Mac game to modern systems. Anyway, no Classic support on Intel, thus no 68k either (and PowerPC only for OS X apps). The PowerPC emulation for Intel (Apple called it "Rosetta") was a licensed third-party product that used JIT-style compilation, but it really only worked for userland programs; it didn't support drivers and it presumably wasn't close enough to the real deal to support the Classic environment, so they dropped it in all Intel versions of Mac OS (10.5 dropped it for PowerPC as well for reasons I don't quite understand, since that was the last PowerPC version). Anyway, given that the PowerPC translation on Intel only lasted through 10.6, and Apple just dropped 32-bit Intel support in 10.15, I would expect backwards compatibility support for Intel apps (if they're even planning it) to drop within 2-3 revisions of macOS after the transition. Just putting that out there. > On Jun 10, 2020, at 8:47 PM, Robert Engels <reng...@ix.netcom.com> wrote: > > When Macs first switched to Intel the OS included a Motorola 68k emulator so > that existing Mac binaries would run. -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/985784B5-328E-42A6-88A4-92B2EC5A3FE1%40gmail.com.
