Thanks, Greg. I learned a lot from you.
-Brian Greg Price ??: >>> >>> >> I know the caller's %o will be the callee's %i after the 'save', but I >> don't think they are saved on the stack when the 'call' or 'save' >> executes. Just as what I mean, these acres are just reserved for >> traps, those registers are saved by the trap handler or the resume(). >> > Correct, they "saved" (by means of spill handlers) to the stack, when we > context switch, execute a flushw instruction, or when a register window > is about to be overwritten (i.e. the window rotates all the way around, > which is about 6 function deep IIRC for the old UltraSPARC processors, > so the save could trigger a spill for a different register window (and > saved into that register windows frame on the stack), and the restore > instruction would load them back into the hardware)... nwindows = 8, > (there is an overlap window), and probably some other circumstances. > > The bottom line is that when a thread is executing, the current contents > aren't necessarily there. > >>>> 3. the callee reserve area for the Locals and temps and outgoing >>>> args past 6. together with the caller's bias area(I don't know how >>>> to express this area, so just name as is), can be accessed by the >>>> callee for its private use. >>>> >>>> >>> We have a minimum stack frame which is large enough to hold the >>> registers + the frame is extended to hold the local variables. The >>> bias isn't an area, think of it like calibrating the steering on a >>> car or remote control boat. i.e. the default position is always >>> offset by a particular amount. >>> >>> >> I know the answer. From the doc you sent to me, I got: >> >> /The SPARC V9 ABI defines the stack pointer to have bias subtracted. >> This means that stack pointer for 64-bit program normally contains an >> misaligned value,but load and store instructions generated by the com- >> piler subtract the required bias to generate the correct address. >> >> /so it is just a definition of the %sp, nothing else. >> > I think "specifies" or "convention" would be better words, but yes. > > > Cheers, > Greg > > _______________________________________________ > mdb-discuss mailing list > mdb-discuss at opensolaris.org >
