From: Mathieu Desnoyers <mathieu.desnoy...@efficios.com> Date: Wed, 19 Jan 2011 17:13:27 -0500
> Hrm, I'd like to see what kind of ill-conceived 32-bit architecture would > generate a unaligned access for a 32-bit aligned u64. Do you have examples in > mind ? By definition, the memory accesses should be at most 32-bit, no ? > AFAIK, > gcc treats u64 as two distinct reads on all 32-bit architectures. Sparc 32-bit has 64-bit loads and stores, GCC uses them because the ABI specifies that every structure is at least 8 byte aligned. > gcc on my sparc64 box (32-bit userland) disagrees with you here ;) Using > gcc (Debian 4.3.3-14) 4.3.3, here is a demonstration that, indeed, "packed" > generates aweful code, but that "packed, aligned(4 or 8)" generates pretty > decent code: Amazing, if this works then do it. But please document this fully with comments and such :-) -- To UNSUBSCRIBE, email to debian-kernel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20110119.142137.184823805.da...@davemloft.net
