From: Jurij Smakov <jurij@xxxxxxxxx> Date: Wed, 12 Oct 2011 22:22:51 +0100 > 0: > xor %fp, %g3, %o0 > add %fp, 512, %o1 > andncc %o0, 4095, %o0 > bne LOC(thread) > cmp %o1, %g3 > bl LOC(thread) > > It looks like this code is *very* old (was added back in 1998, it > seems [0]), so I was not able to find any description for it. If you > don't mind explaining what's going on here, I would appreciate it. > > [0] http://lwn.net/1998/1022/a/sparc-glibc-patch.html > > Best regards, This code is seeing if the current stack/frame pointers are on a different "page" or very far from the stack/frame we are unwinding into. The thinking is that if the distance is very large, then the loop is unlikely to be more efficient, or we are unwinding out-of or into a different kind of stack (thread stack, process stack, signal stack, etc.). -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
