Messages in this thread | | | From | Vineet Gupta <> | Subject | Re: single copy atomicity for double load/stores on 32-bit systems | Date | Mon, 3 Jun 2019 18:08:35 +0000 |
| |
On 5/31/19 1:21 AM, Peter Zijlstra wrote: >> I'm not sure how to interpret "natural alignment" for the case of double >> load/stores on 32-bit systems where the hardware and ABI allow for 4 byte >> alignment (ARCv2 LDD/STD, ARM LDRD/STRD ....) > Natural alignment: !((uintptr_t)ptr % sizeof(*ptr)) > > For any u64 type, that would give 8 byte alignment. the problem > otherwise being that your data spans two lines/pages etc..
Sure, but as Paul said, if the software doesn't expect them to be atomic by default, they could span 2 hardware lines to keep the implementation simpler/sane.
| |