It turns out that calling Sys_Shutdown in the signal handler can cause
lockups due to the signal occurring at unsafe times. Fortunately, this is
just the IO related signals (INT, HUP, TERM, QUIT) as the others are
usually caused by actual errors and should not occur in system code thus
timing should not be an issue. However, care will need to be taken when it
comes to handling SIGINT or similar for breaking runaway progs code when
that time comes.
While QF doesn't currently use nanoseconds, having access to a clock
that is not affected by setting system time is nice, and as a bonus, can
handle suspends should the need arise.
This reduces the overhead needed to manage the memory blocks as the
blocks are guaranteed to be page-aligned. Also, the superblock is now
alllocated from within one of the memory blocks it manages. While this
does slightly reduce the available cachelines within the first block (by
one or two depending on 32 vs 64 bit pointers), it removes the need for
an extra memory allocation (probably via malloc) for the superblock.
The uptime display had not been updated for the offset Sys_DoubleTime,
so add Sys_DoubleTimeBase to make it easy to use Sys_DoubleTime as
uptime.
Line up the layout of the client list was not consistent for drop and
qport.
If Sys_Shutdown gets called twice, particularly if a shutdown callback
hangs and the program is killed with INT or QUIT, shutdown_list would be
in an invalid state. Thus, get the required data (function pointer and
data pointer) from the list element, then unlink the element before
calling the function. This ensures that a reinvocation of Sys_Shutdown
continues from the next callback or ends cleanly. Fixes a segfault when
killing testsound while using the oss output (it hangs on shutdown).
I'm not sure that the mismatch between refdef_t and the assembly defines
was a problem (many fields unused), but the main problem was due to
execute permission on the pages: one chunk of asm was in the data
section, and the patched code was not marked as being executable (due to
such a thing not existing when quake was written).
Sys_LongTime returns time in microseconds as a 64-bit int. Sys_DoubleTime
uses Sys_LongTime, converts to double and offsets 0 time by 4G (2**32).
This gives us consistent sub-microsecond precision for a very long time.
See http://randomascii.wordpress.com/2012/02/13/dont-store-that-in-a-float/
The ~ gets expanded to CSIDL_LOCAL_APPDATA, $HOME, $USERPROFILE or just
".", whichever succeeds first. The usual location will be:
"C:\windows\profiles\<user>\Local Settings\Application Data".
"." is now the fallback for *nix systems too.
One's an actual bug, the other a bit of error checking (not sure how
necessary it is, but it's in code that we don't /want/ to run, so it can't
hurt :)
