Attached is a set of patches to port the precise timer that is currently used in the Linux and BeOS builds of SheepShaver to Mac OS X (and any other Mach-based operating systems).
Currently, the Linux build uses the clock_gettime() function to get nanosecond-precision time, and falls back on gettimeofday() if it is not present. Unfortunately, Mac OS X does not currently support clock_gettime(), and gettimeofday() has only microsecond granularity. The Mach kernel, however, has a clock_get_time() function that does very nearly the same thing as clock_gettime(). The patches to BasiliskII cause the timing functions such as timer_current_time() to use clock_get_time() instead of gettimeofday() on Mach-based systems that do not support clock_gettime().
The changes to SheepShaver involve the precise timer. The existing code for Linux uses pthreads and real-time signals to handle the timing. Mac OS X unfortunately does not seem to support real-time signals, so Mach calls are again used to suspend and resume the timer thread in order to attempt to duplicate the Linux and BeOS versions of the timer. The code is somewhat ugly right now, as I decided to leave alone the pre-existing style of the source file, which unfortunately involves #ifdefs scattered throughout the file and some duplication of code. A future patch may want to clean this up to separate out the OS-specific code and put it all together at the top of the file. However, for the time being, this seems to work.
This has not been extensively tested, because I have not been able to get my hands on a good test-case app for the classic Mac OS that would run inside the emulator and try out the timer. However, performance does seem to be better than with the pre-existing code, and nothing seems to have blown up as far as I can tell. I did find a game via a Google search - Cap'n Magneto - that is known to have problems with Basilisk/SheepShaver's legacy 60 Hz timer, and the opening fade-to-color for this game appears to run much more smoothly with the precise timer code in place.
On those systems, it's really hard to get high resolution timings and the
system oftens fails to honour a timeout in less than 20 ms. The idea here
is to have an average m68k instruction count (countdown quantum) that
triggers real interrupt checks. The quantum is calibrated every 10 ticks
and has a 1000 Hz resolution on average.
to "true". This uses the BSD socket API, so it's fairly portable (currently
only imeplemented under Unix, though). This works by sending raw Ethernet
packets as UDP packets to a fixed port number ("udpport", default is 6066),
using IP broadcasts to simulate Ethernet broad- and multicasts. Currently
only tested with AppleTalk.
implemented under Unix
- adb.cpp uses mutexes for thread-safe mouse handling
- video_x.cpp: pressing Ctrl-F5 in windowed mode switches to a "grabbed"
relative mouse mode, useful for some games
- video_x.cpp: fixed some bugs relating to the hotkeys (key releases are no
longer treated as hotkeys)
- new utility functions Mac_memset, Mac2Host_memcpy, Host2Mac_memcpu and
Mac2Mac_memcpy
- extfs.cpp: fixed bug in fs_rename() and fs_cat_move() (auxiliary IOParam
block was not in Mac address space)
- some provisions for using UAE CPU compiler (doesn't work yet)
- extfs.cpp: fixed bug with fsResolveWDCB in fs_get_wd_info()
- ExtFS: MAX_PATH_LENGTH is global, removed third parameter to
add_path_component()
- rom_patches.cpp: added print_rom_info()
- Unix: added "-rominfo" command line argument
- extfs_unix.cpp: supports finder info and resource forks
- prefs_editor_gtk.cpp: tab widget is no longer scrollable