GCC has become too smart - we need to slice the binary created to be sure the
address of the trap is within the test addresses. This is why each trap occurs
between two case labels and a new section of assembly code is set in between.
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.
SheepShaver includes the C errno string in many error messages. One case is when it calls the memory allocation routines in the Basilisk II vm_alloc.cpp program.
This works when the memory allocation routine uses functions that set errno (such as mmap or malloc). For example, running SheepShaver on a Linux hosts produces meaningful error messages.
The problem is that when run on an OS X host, the memory allocation uses Mach routines such as vm_allocate, which do not set errno.
So when SheepShaver reported the error, it used a stale value of errno, which happened to be 17. The result was an extremely misleading error message: "Cannot map RAM: File already exists".
The fix is to change vm_alloc so that it translates Mac return codes into POSIX errno values.
It also initializes errno to 0 at the start of the memory allocation routine, so that no matter what path it takes, it won't return a stale value.
Here is a patch to allow compiling of SS and B2 with an SDL Framework. You can
get this by downloading from:
http://www.libsdl.org/release/SDL-1.2.13.dmg
Here is how I tested on an intel 32-bit mac with Mac OS X 10.5.6:
SS ./autogen.sh --disable-standalone-gui --enable-vosf --enable-sdl-framework --enable-sdl-framework-prefix=/Users/mzs/Library/Frameworks --enable-sdl-video --disable-sdl-audio --enable-addressing=real
--without-esd --without-gtk --without-mon --without-x
SS /autogen.sh --disable-standalone-gui --enable-vosf --disable-sdl-framework --disable-sdl-video --disable-sdl-audio --enable-addressing=real --without-esd --without-gtk --without-mon --with-x
B2 ./autogen.sh --disable-standalone-gui --enable-vosf --enable-sdl-framework --enable-sdl-framework-prefix=/Users/mzs/Library/Frameworks --enable-sdl-video --enable-sdl-audio --enable-addressing=real --without-esd --without-gtk --without-mon --without-x --enable-jit-compiler
B2 ./autogen.sh --disable-standalone-gui --enable-vosf --disable-sdl-framework --disable-sdl-video --disable-sdl-audio --enable-addressing=real --with-esd --without-gtk --without-mon --with-x --enable-jit-compiler
(esound does not really work on mac, it needs some better coreaudio patches.)
configure.ac for SS has two little additional fixes so that the Cocoa prefs gui
does not get built if you are building for X11 and so that you can use esd, sdl,
or coreaudio for sound.
I was testing some other SS patches and I noticed that when I ran an X11
build of SS there were not all the video modes I expected in the the
control strip. Mac OS X 10.5 changed the form of the DISPLAY environment
variable. The reason for this is that the DISPLAY variable looks like
this in Leopard:
/tmp/launch-XXXXXX/:0
The Xs are like in mktemp.
Here is a patch that has a shell script cpr.sh to recursively copy directories but
discarding things that cause problems at least on 10.4 when making the .app bundles.
This first patch gets B2 and SS to build under Leopard and Tiger.
I tested this on a 32-bit intel 10.5.6 mac like so:
B2
./autogen.sh --disable-standalone-gui --enable-vosf --enable-sdl-video --enable-sdl-audio --enable-addressing=real --without-esd --without-gtk --without-mon --without-x
SS
./autogen.sh --disable-standalone-gui --enable-vosf -enable-sdl-video --disable-sdl-audio --enable-addressing=real --without-esd --without-gtk --without-mon --without-x --enable-jit
There is also a little tweak so that you can use sdl audio in SheepShaver when building for Mac OS X.
explicitly generated from mig. The advantage of that is to provide a "fast"
path for x86_64 on Leopard too (fault address in code[1]).
By "fast", this means +33% faster wrt. explicitly thread_get_state() but
still pretty slow (40 usec/fault). This is on par with the i386 code path though.
Leopard kernel faster? This is pure marketing hype. For 32-bit applications,
Mach exception recovery is 60% slower. For 64-bit applications, this is up
to 40% faster though. In any case, MacOS X remains pretty slow wrt. Linux...
environment variable: SIGSEGV_MACH_FAULT. It can be set to "direct" to
assume the fault address comes from code[1] argument, or "slow" to use
the slow path through thread_get_status(EXCEPTION_STATE)->faultvaddr.
in the bundle. This is faster and more accurate as this avoids emulation.
Also clean-up code so that to prepare the use of lib uaccess on hpux/ia64.
XXX: this will need explicit use of uint64_t to define registers because
HP/UX is ILP32 capable and all registers are 64-bit capable so "unsigned long"
won't fit.
complex than expected but it was fun to play with. Who designed this ISA?
I'd love to see how the decoder is implemented in HW, by all means it is
not "simplified" unless I missed some pattern...
XNU 792.21.3 (10.4.10) and XNU 1228 (10.5.0), exception handler code[1] always
contains the fault address nowadays. So make it the default fast path but keep
provisions to check that at run-time first.
This yields a nearly 4x improvement in SIGSEGV recovery but MacOS X is still
suboptimal wrt. Linux, so VOSF is still not possible with frameskip == 0.
XXX: the ppc kernel had bugs that caused DAR (put into code[1]) to be incorrectly
decoded. This would need a broader test audience or more careful audit of the
sources changes.
on Tiger+ to store FInfo and FXInfo. Otherwise, plain old .finfo/ helpers are
used. "Safe" flags and fields are always synchronized to/from MacOS X.
BTW, CFString leak was fixed at the same time.
I am adding functionality to support this. For the moment, I've only
added the platform-specific conversion for MacOSX (ie: UTF8 -> MacRoman),
but others can be added later.
Rather, use an address override prefix (0x67) though Intel Core optimization
reference guide says to avoid LCP prefixes. In practise, impact on performance
is measurably marginal on e.g. Speedometer tests.
- Don't export transfer types definitions (formerly used by older API)
- Handle ADD instructions in ix86_skip_instruction() (generated by icc 9.1)
- Use "%p" format for EIP/RIP addresses
- Call user handler for KERN_INVALID_ADDRESS too (SIGBUS)
- Check for VALID_THREAD_STATE_FLAVOR in forward_exception()
- Return KERN_FAILURE if forward_exception() got an unknown behavior code
Other bugs fixed:
- CD-ROM media are polled and now can be changed without rebooting
- Buffer overflow, memory leak and extra wait in CD-ROM ejection code
as BasiliskIIGUI.app, or /Applications/BasiliskII.app if none was found.
Also make yet another arrangement for MacOS X "difference". This scenario
was not working: WarningAlert -> ErrorAlert, the latter was not performed
because the exit status was not properly filled in sip->si_status...
- Rewrote dispatch loop to accomodate GTK+1.2 for MacOS X (which doesn't
like threads nor forks(!)). The latter also requires an additional patch
to the version 0.7 available on SourceForge
- Run-time detect JIT capability so that we could hopefully use the ppc GUI
on intel based Macs (check!)
STANDALONE_GUI. This is the second step towards a more interesting GUI alike
to VMware. Communication from/to the GUI is held by some lightweight RPC.
Note: The step should be enough to provide a tiny GTK GUI for MacOS X.
