On Jan 9, 2013, at 12:01 PM, Kyle Sluder <k...@ksluder.com> wrote: > On Wed, Jan 9, 2013, at 11:04 AM, John McCall wrote: >> There is no one standard calling convention on ARM; ARM has revised its >> suggested ABI multiple times. iOS follows a relatively old convention >> which, among other things, does not pass floating-point arguments in >> floating-point registers. This is suboptimal but not fixable without a >> total ABI break. > > That's what I was afraid of. :( Did Apple take advantage of the move to > ARMv7 to introduce a more performant calling convention?
No. On iOS, ARMv7 and ARMv6 code can interoperate freely, so there was no opportunity to introduce changes to parameter-passing. Without heroic measures, a true ABI break means either "your old apps don't work" or "there are two copies of the OS shared library stack in memory". The sub-optimal parts of our ARM ABI aren't bad enough to justify that cost. -- Greg Parker gpar...@apple.com Runtime Wrangler _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
