> According to comment in exec-all.h: > /* Deterministic execution requires that IO only be performed on the last > instruction of a TB so that interrupts take effect immediately. */ > > Sparc generator must then violate this assumption. Is the assumption > valid also when not using icount and should the check be enabled for > all cases, not just icount?
Not really. With -icount we're trying to achieve deterministic behavior[1]. When icount is disabled a few extra instructions interrupt latency is the least of your problems. I guess with in-core peripherals you may be able to accurately predict interrupt response. However for the vast majority of cases I wouldn't be surprised if real hardware has a few cycles latency anyway. Paul [1] Even with -icount, qemu is still a long way from being cycle accurate. The goal is to give reproducible and consistent results. Actual realtime characteristics are still likely to be very different from real hardware. Paul
