Attached is a patch to SheepShaver to fix memory allocation problems when OS X 10.5 is the host. It also relaxes the 512 MB RAM limit on OS X hosts.
Problem
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Some users have been unable to run SheepShaver on OS X 10.5 (Leopard) hosts. The symptom is error "ERROR: Cannot map RAM: File already exists".
SheepShaver allocates RAM at fixed addresses. If it is running in "Real" addressing mode, and can't allocate at address 0, then it was hard-coded to allocate the RAM area at 0x20000000. The ROM area as allocated at 0x40800000.
The normal configuration is for SheepShaver to run under SDL, which is a Cocoa wrapper. By the time SheepShaver does its memory allocations, the Cocoa application has already started. The result is the SheepShaver memory address space already contains libraries, fonts, Input Managers, and IOKit areas.
On Leopard hosts these areas can land on the same addresses SheepShaver needs, so SheepShaver's memory allocation fails.
Solution
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The approach is to change SheepShaver (on Unix & OS X hosts) to allocate the RAM area anywhere it can find the space, rather than at a fixed address.
This could result in the RAM allocated higher than the ROM area, which causes a crash. To prevent this from occurring, the RAM and ROM areas are allocated contiguously.
Previously the ROM starting address was a constant ROM_BASE, which was used throughout the source files. The ROM start address is now a variable ROMBase. ROMBase is allocated and set by main_*.cpp just like RAMBase.
A side-effect of this change is that it lifts the 512 MB RAM limit for OS X hosts. The limit was because the fixed RAM and ROM addresses were such that the RAM could only be 512 MB before it overlapped the ROM area.
Impact
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The change to make ROMBase a variable is throughout all hosts & addressing modes.
The RAM and ROM areas will only shift when run on Unix & OS X hosts, otherwise the same fixed allocation address is used as before.
This change is limited to "Real" addressing mode. Unlike Basilisk II, SheepShaver *pre-calculates* the offset for "Direct" addressing mode; the offset is compiled into the program. If the RAM address were allowed to shift, it could result in the RAM area wrapping around address 0.
Changes to main_unix.cpp
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1. Real addressing mode no longer defines a RAM_BASE constant.
2. The base address of the Mac ROM (ROMBase) is defined and exported by this program.
3. Memory management helper vm_mac_acquire is renamed to vm_mac_acquire_fixed. Added a new memory management helper vm_mac_acquire, which allocates memory at any address.
4. Changed and rearranged the allocation of RAM and ROM areas.
Before it worked like this:
- Allocate ROM area
- If can, attempt to allocate RAM at address zero
- If RAM not allocated at 0, allocate at fixed address
We still want to try allocating the RAM at zero, and if using DIRECT addressing we're still going to use the fixed addresses. So we don't know where the ROM should be until after we do the RAM. The new logic is:
- If can, attempt to allocate RAM at address zero
- If RAM not allocated at 0
if REAL addressing
allocate RAM and ROM together. The ROM address is aligned to a 1 MB boundary
else (direct addressing)
allocate RAM at fixed address
- If ROM hasn't been allocated yet, allocate at fixed address
5. Calculate ROMBase and ROMBaseHost based on where the ROM was loaded.
6. There is a crash if the RAM is allocated too high. To try and catch this, check if it was allocated higher than the kernel data address.
7. Change subsequent code from using constant ROM_BASE to variable ROMBase.
Changes to Other Programs
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emul_op.cpp, main.cpp, name_registery.cpp, rom_patches.cpp, rsrc_patches.cpp, emul_ppc.cpp, sheepshaver_glue.cpp, ppc-translate-cpp:
Change from constant ROM_BASE to variable ROMBase.
ppc_asm.S: It was setting register to a hard-coded literal address: 0x40b0d000. Changed to set it to ROMBase + 0x30d000.
ppc_asm.tmpl: It defined a macro ASM_LO16 but it assumed that the macro would always be used with operands that included a register specification. This is not true. Moved the register specification from the macro to the macro invocations.
main_beos.cpp, main_windows.cpp: Since the subprograms are all expecting a variable ROMBase, all the main_*.cpp pgrams have to define and export it. The ROM_BASE constant is moved here for consistency. The mains for beos and windows just allocate the ROM at the same fixed address as before, set ROMBaseHost and ROMBase to that address, and then use ROMBase for the subsequent code.
cpu_emulation.h: removed ROM_BASE constant. This value is moved to the main_*.cpp modules, to be consistent with RAM_BASE.
user_strings_unix.cpp, user_strings_unix.h: Added new error messages related to errors that occur when the RAM and ROM are allocated anywhere.
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.
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.
Makes SheepShaver compatible with Ubuntu Intrepid and
other distros that bundle the gcc-4.3 compiler.
The patch changes two things:
1. Renames the block_cache where its name collides with its class
definition.
2. Fixes the "explicit template specialization cannot have a storage
class" error in the ppc-dyngen-ops.cpp file.
Software cursor mode is now supported, although currently the existing hardware
cursor mode is used whenever possible. (Software mode will be used if you are
running with a recent version of SDL's Quartz video driver, since a bug in SDL
1.2.11 and later prevents the hardware cursor from working properly with that
driver.)
In hardware cursor mode, the hot-spot is now determined heuristically. Formerly
it could not be determined and was always (1,1), an annoyance for many cursors
other than the arrow.
In hardware cursor mode, the cursor will now be hidden when requested by the
emulated OS (such as when you are typing in a text field).
In hardware cursor mode, some cursor image formats that the code does not handle
correctly will now be rejected, causing the emulated OS to revert temporarily to
software cursor mode. Formerly you would just end up with random garbage for a
cursor. This typically happened for grayscale or color cursors; rejecting images
with rowBytes != 2 eliminates the worst cases.
clicks to right-clicks and option-clicks to middle-clicks, a feature intended
for Mac users with single-button mice who are running SDL-based games that
require a multi-button mouse. This is unhelpful in SheepShaver, where we want
command-clicks and option-clicks to be passed through unchanged to the emulated
Mac OS. We can disable the unwanted behavior by setting an environment variable
SDL_HAS3BUTTONMOUSE intended for this very purpose.
A similar change in main_windows.cpp is NOT required, because only the Quartz
video implementation is involved.
By SDL convention, putenv is used in preference to setenv, although for Unix
platforms it doesn't matter.
to cache the CPU context pointer to a register and thus rendering generated
code CPU context independent. Not useful to SheepShaver, but it is for
another project for threads emulation on plain x86-32.
Note: AltiVec performance may drop a little on x86 but this will be restored
(and even improved) in the future.
