On Mon, Aug 12, 2013 at 12:12 PM, Franck Jullien <[email protected]> wrote: > Hi Julius, > > 2013/8/12 Julius Baxter <[email protected]>: >> On Sun, Aug 11, 2013 at 11:06 PM, Franck Jullien >> <[email protected]> wrote: >>> Hi, >>> >>> In the original patch we substituted the pc with the npc value while >>> flushing the pipe after a dbg_stall disassertion. This doesn't work >>> everytime because npc might not be always equal the the bp address. >>> >>> In this patch, we save the npc content when the dbg_stall occurs >>> (saved_npc). This value will be used to set the pc after a dbg_stall >>> disassertion. >> >> Hi Franck, >> >> This makes sense. However, what happens if we hit a breakpoint and >> then set a new NPC via the debugger? It looks like we can resume from >> the saved PC only, and not a newly written one. I think you'll need a >> mechanism for detecting a write to the NPC while the CPU is stalled >> and resuming from that address. >> >> Also, this saved address doesn't look like it's accessible by reading >> the NPC in SPR space. Surely being able to read the actual NPC you're >> going to resume from is important. I presume the NPC register doesn't >> hold the right value here, and if so, that's not great. >> >> Or maybe I'm not reading the patch correctly? >> > > To be honest, I didn't ask myself all those questions :) I just patch > it to make it work in my test case. > I'll see what I can do. I just wanted to close the debug thing case.
How about you use the condition where you save the NPC in the new register to just write to the actual NPC SPR internally (or stop it from being updated, whatever the case may be)? That would be a small change, and it would then be visible to the debugger and you could change it if you liked. > >> Oh, one more small thing - patches inline next time please ;) >> > > Well, I usually send patch using git send-email however, as it is a > svn diff I didn't want to paste it in my email. > I think it's easier to apply if you have it as an attachment. I could do both. Yeah, true, SVN doesn't have a nice send-email thing like git. I normally just copy paste it in (although, that did screw up a few patches, so maybe your method is best, but it's easier to comment on the patch if it's inline). Cheers Julius _______________________________________________ OpenRISC mailing list [email protected] http://lists.openrisc.net/listinfo/openrisc
