2. Fixed bug
[ 989478 ] I-Cache and undefined Instruktions
The L4 microkernel uses an undefined instruction to
trap for a special requests into the kernel (LOCK NOP).
The handler fixes this up and gives the user a special
code page with syscall stubs. If you're not using the
I-Cache optimization everthing works find on bochs. But
if you enable the I-Cache (--enable-icache), then the
undefined opcode exception is thrown only once for ever
virtual address it occurs. See the demodisk of the
L4KA::pistachio
(http://www.l4ka.org/projects/pistachio/download.php).
In this case the pingpong benchmark of this demo is of
interest. Everything runs fine until the program tries
to spawn a new task for its measurements. This new task
shares the code of the creating program. But the new
task stops executing at the undefined instruction
explained above and no exception is thrown.
configure script option --enable-magic-breakpoints (enabled by default).
Documented the instruction required to trigger the magic breakpoint
(xchgw %bx,%bx).
* renamed CPU_ID to BX_CPU_ID.
with this new name there is no possibility for name contentions and BX_CPU_ID
definition could be moved out to NEED_CPU_REG_SHORTCUTS block
* returned back `unsigned BX_CPU::which_cpu(void)` function
* added BX_CPU_ID parameter for
BX_INSTR_PHY_READ(a20addr, len);
BX_INSTR_PHY_WRITE(a20addr, len);
now it will be
BX_INSTR_PHY_READ(cpu_id, a20addr, len);
BX_INSTR_PHY_WRITE(cpu_id, a20addr, len);
In bx_cpu_c::reset method I set bx_cpu->async_event to 2
so execution in the cpu_loop gets stopped early.
Previously, async_event was set to 0, and with repeatable
instructions, after reset, eip was incremented by the instruction
length, so execution would resume at 0xffffX (X being >0, the current
instruction length).
In halt state I check now for reset with async_event is 2, so
reset works also when the cpu is halted. (update to Peter change)
I hope I fixed this the right way, please report any strange behaviour.
"bx_bool" which is always defined as Bit32u on all platforms. In Carbon
specific code, Boolean is still used because the Carbon header files
define it to unsigned char.
- this fixes bug [ 623152 ] MacOSX: Triple Exception Booting win95.
The bug was that some code in Bochs depends on Boolean to be a
32 bit value. (This should be fixed, but I don't know all the places
where it needs to be fixed yet.) Because Carbon defined Boolean as
an unsigned char, Bochs just followed along and used the unsigned char
definition to avoid compile problems. This exposed the dependency
on 32 bit Boolean on MacOS X only and led to major simulation problems,
that could only be reproduced and debugged on that platform.
- On the mailing list we debated whether to make all Booleans into "bool" or
our own type. I chose bx_bool for several reasons.
1. Unlike C++'s bool, we can guarantee that bx_bool is the same size on all
platforms, which makes it much less likely to have more platform-specific
simulation differences in the future. (I spent hours on a borrowed
MacOSX machine chasing bug 618388 before discovering that different sized
Booleans were the problem, and I don't want to repeat that.)
2. We still have at least one dependency on 32 bit Booleans which must be
fixed some time, but I don't want to risk introducing new bugs into the
simulation just before the 2.0 release.
Modified Files:
bochs.h config.h.in gdbstub.cc logio.cc main.cc pc_system.cc
pc_system.h plugin.cc plugin.h bios/rombios.c cpu/apic.cc
cpu/arith16.cc cpu/arith32.cc cpu/arith64.cc cpu/arith8.cc
cpu/cpu.cc cpu/cpu.h cpu/ctrl_xfer16.cc cpu/ctrl_xfer32.cc
cpu/ctrl_xfer64.cc cpu/data_xfer16.cc cpu/data_xfer32.cc
cpu/data_xfer64.cc cpu/debugstuff.cc cpu/exception.cc
cpu/fetchdecode.cc cpu/flag_ctrl_pro.cc cpu/init.cc
cpu/io_pro.cc cpu/lazy_flags.cc cpu/lazy_flags.h cpu/mult16.cc
cpu/mult32.cc cpu/mult64.cc cpu/mult8.cc cpu/paging.cc
cpu/proc_ctrl.cc cpu/segment_ctrl_pro.cc cpu/stack_pro.cc
cpu/tasking.cc debug/dbg_main.cc debug/debug.h debug/sim2.cc
disasm/dis_decode.cc disasm/disasm.h doc/docbook/Makefile
docs-html/cosimulation.html fpu/wmFPUemu_glue.cc
gui/amigaos.cc gui/beos.cc gui/carbon.cc gui/gui.cc gui/gui.h
gui/keymap.cc gui/keymap.h gui/macintosh.cc gui/nogui.cc
gui/rfb.cc gui/sdl.cc gui/siminterface.cc gui/siminterface.h
gui/term.cc gui/win32.cc gui/wx.cc gui/wxmain.cc gui/wxmain.h
gui/x.cc instrument/example0/instrument.cc
instrument/example0/instrument.h
instrument/example1/instrument.cc
instrument/example1/instrument.h
instrument/stubs/instrument.cc instrument/stubs/instrument.h
iodev/cdrom.cc iodev/cdrom.h iodev/cdrom_osx.cc iodev/cmos.cc
iodev/devices.cc iodev/dma.cc iodev/dma.h iodev/eth_arpback.cc
iodev/eth_packetmaker.cc iodev/eth_packetmaker.h
iodev/floppy.cc iodev/floppy.h iodev/guest2host.h
iodev/harddrv.cc iodev/harddrv.h iodev/ioapic.cc
iodev/ioapic.h iodev/iodebug.cc iodev/iodev.h
iodev/keyboard.cc iodev/keyboard.h iodev/ne2k.h
iodev/parallel.h iodev/pci.cc iodev/pci.h iodev/pic.h
iodev/pit.cc iodev/pit.h iodev/pit_wrap.cc iodev/pit_wrap.h
iodev/sb16.cc iodev/sb16.h iodev/serial.cc iodev/serial.h
iodev/vga.cc iodev/vga.h memory/memory.h memory/misc_mem.cc
bx_shadow_num_c able to handle pointers to 64 bit values. This
allows x86-64 and wxWindows to coexist.
- I had a number of duplicate constructors for bx_shadow_num_c,
with an without the description arg. I eliminated the ones
that had no description, and also removed the min/max arg from
all. I still need a bunch of constructors though, for
Bit64u*, Bit64s*, Bit32u*, Bit32s*, Bit16u*, Bit16s*, Bit8u*, Bit8s*.
Having all these constructors allows us to write
new bx_shadow_num (bxid, name, description, &value)
for basically any integer variable. They are all handled by the same class.
- these changes led to minor touchups in cpu/init.cc and iodev/keyboard.cc
- modified:
configure main.cc cpu/init.cc iodev/keyboard.cc
gui/siminterface.cc gui/siminterface.h
restart another one in wxWindows. Fixed that. Also, on restart, the
apic id's left over from the first run were causing panics. Fixed that.
- modified: main.cc cpu/apic.cc cpu/cpu.h cpu/init.cc
now simply return a cached value which is set upon mode changes.
The biggest problem was protected_mode() which did something like:
return CR0.PM && ! EFLAGS.VM
This adds up when it was being executed many times in branch functions
etc. Now, cached values are set and sampled instead.
Some things changed in the ctrl_xfer*.cc, fetchdecode*.cc,
and cpu.cc since the original patches, so I did some patch
integration by hand. Check the placement of the
macros BX_INSTR_FETCH_DECODE_COMPLETED() and BX_INSTR_OPCODE()
in cpu.cc to make sure I go them right. Also, I changed the
parameters to BX_INSTR_OPCODE() to update them to the new code.
I put some comments before each of these to help determine if
the placement is right.
These macros are only compiled in if you are gathering instrumentation
data from bochs, so they shouldn't effect others.
of (1 & (val32>>N)), and added a getB_?F() accessor for special
cases which need a strict binary value (exactly 0 or 1). Most
code only needed a value for logical comparison. I modified the
special cases which do need a binary number for shifting and
comparison between flags, to use the special getB_?F() accessor.
Cleaned up memory.cc functions a little, now that all accesses
are within a single page.
Fixed a (not very likely encountered) bug in fetchdecode.cc (and
fetchdecode64.cc) where a 2-byte opcode starting with a prefix
starts at the last offset on a page. There were no checks
on the segment overrides for a boundary condition. I added them.
The eflags enhancements added just a tiny bit of performance.
but if you hand edit cpu/cpu.h, and change BxICacheEntries,
you can try different sizes. I'll make this more flexible
with configure. For now, use "--enable-icache" with no parameters.
- Modified fetchdecode.cc/fetchdecode64.cc just enough so that
instructions which encode a direct address now use a memory
resolution function which just sticks the immediate address
into rm_addr. With cached instructions we need this.
read all param values from CPU #0. The only solution I can come up with
is to change the siminterface handler function interface to pass a void*
to the callback function. I'll take care of it eventually.
be used at all, and Peter didn't want it. "extdb.o" is compiled
into libcpu.a, if configured for it.
Removed a few #warnings for x86-64 compile, based on Peter's
line-item comments regarding the warnings I inserted during
the port/merge.
Bochs debugger. The Bochs debugger calls SIM->debug_get_next_command() which
does not return until a debugger command is found. The siminterface sends an
synchronous event to the wxWindows thread with a blank to be filled in with a
debugger command. wxWindows fills in the blank and sends the synchronous
event back, and the Bochs debugger interprets it as if it was typed on
the command line. For the long term I haven't decided whether to stick with
sending text strings vs. some other method.
- so far the wxWindows debugger consists of one big dialog box that shows
all the standard registers, and a working Continue, Stop, and Step button.
- modify ParamDialog so that it is more useful as a base class, by moving
some things to protected members&fields, separating out functionality
that is most likely to be replaced into virtual functions, and making it
generally more flexible. The new CpuRegistersDialog is based on
ParamDialog.
- in wxdialog.cc, continue the convention of using wxID_HELP, wxID_OK,
wxID_CANCEL, etc. for the id's of buttons, instead of wxHELP, wxOK, etc.
which are intended to be ORred together in a bit field.
- cpu/init.cc: put ifdefs around DEFPARAMs for flags in configurations
where they don't exist. Add an eflags shadow parameter that represents all
of the bits of eflags at once. There are also boolean shadow params for
each bit.
- modified files: cpu/init.cc debug/dbg_main.cc debug/debug.h
gui/siminterface.cc gui/siminterface.h gui/wxdialog.cc gui/wxdialog.h
gui/wxmain.cc gui/wxmain.h
cpu64 directories. Instead of using the macros introduced in cpu.h rev 1.37
such as GetEFlagsDFLogical and SetEFlagsDF and ClearEFlagsDF, I made inline
methods on the BX_CPU_C object that access the eflags fields. The problem
with the macros is that they cannot be used outside the BX_CPU_C object. The
macros have now been removed, and all references to eflags now use these new
accessors.
- I debated whether to put the accessors as members of the BX_CPU_C object
or members of the bx_flags_reg_t struct. I chose to make them members
of BX_CPU_C for two reasons: 1. the lazy flags are implemented as
members of BX_CPU_C, and 2. the eflags are referenced in many many places
and it is more compact without having to put eflags in front of each. (The
real problem with compactness is having to write BX_CPU_THIS_PTR in front of
everything, but that's another story.)
- Kevin pointed out a major bug in my set accessor code. What a difference a
little tilde can make! That is fixed now.
- modified: load32bitOShack.cc debug/dbg_main.cc
and in both cpu and cpu64 directories:
cpu.cc cpu.h ctrl_xfer_pro.cc debugstuff.cc exception.cc flag_ctrl.cc
flag_ctrl_pro.cc init.cc io.cc io_pro.cc proc_ctrl.cc soft_int.cc
string.cc vm8086.cc
> This is the bug fix to make the reset button work properly when the cpu
> is in the halt state. There is another patch in init.cc as well to clear
> async_event. If you don't do this, if a cpu goes into HLT, the only thing
> which will fix it is another interrupt. The reset button won't work.
a consistent way of accessing these flags that works both inside and
outside the BX_CPU class, I added inline accessor methods for each
flag: assert_FLAG(), clear_FLAG(), set_FLAG(value), and get_FLAG ()
that returns its value. I use assert to mean "set the value to one"
to avoid confusion, since there's also a set method that takes a value.
- the eflags access macros (e.g. GetEFlagsDFLogical, ClearEFlagsTF) are
now defined in terms of the inline accessors. In most cases it will
result in the same code anyway. The major advantage of the accesors
is that they can be used from inside or outside the BX_CPU object, while
the macros can only be used from inside.
- since almost all eflags were stored in val32 now, I went ahead and
removed the if_, rf, and vm fields. Now the val32 bit is the
"official" value for these flags, and they have accessors just like
everything else.
- init.cc: move the registration of registers until after they have been
initialized so that the initial value of each parameter is correct.
Modified files:
debug/dbg_main.cc cpu/cpu.h cpu/debugstuff.cc cpu/flag_ctrl.cc
cpu/flag_ctrl_pro.cc cpu/init.cc
All the EFLAGS bits used to be cached in separate fields. I left
a few of them in separate fields for now - might remove them
at some point also. When the arithmetic fields are known
(ie they're not in lazy mode), they are all cached in a
32-bit EFLAGS image, just like the x86 EFLAGS register expects.
All other eflags are store in the 32-bit register also, with
a few also mirrored in separate fields for now.
The reason I did this, was so that on x86 hosts, asm() statements
can be #ifdef'd in to do the calculation and get the native
eflags results very cheaply. Just to test that it works, I
coded ADD_EdId() and ADD_EwIw() with some conditionally compiled
asm()s for accelerated eflags processing and it works.
-Kevin
- modified files: config.h.in cpu/init.cc debug/dbg_main.cc gui/control.cc
gui/siminterface.cc gui/siminterface.h gui/wxdialog.cc gui/wxdialog.h
gui/wxmain.cc gui/wxmain.h iodev/keyboard.cc
----------------------------------------------------------------------
Patch name: patch.wx-show-cpu2
Author: Bryce Denney
Date: Fri Sep 6 12:13:28 EDT 2002
Description:
Second try at implementing the "Debug:Show Cpu" and "Debug:Show
Keyboard" dialog with values that change as the simulation proceeds.
(Nobody gets to see the first try.) This is the first step toward
making something resembling a wxWindows debugger.
First, variables which are going to be visible in the CI must be
registered as parameters. For some variables, it might be acceptable
to change them from Bit32u into bx_param_num_c and access them only
with set/get methods, but for most variables it would be a horrible
pain and wreck performance.
To deal with this, I introduced the concept of a shadow parameter. A
normal parameter has its value stored inside the struct, but a shadow
parameter has only a pointer to the value. Shadow params allow you to
treat any variable as if it was a parameter, without having to change
its type and access it using get/set methods. Of course, a shadow
param's value is controlled by someone else, so it can change at any
time.
To demonstrate and test the registration of shadow parameters, I
added code in cpu/init.cc to register a few CPU registers and
code in iodev/keyboard.cc to register a few keyboard state values.
Now these parameters are visible in the Debug:Show CPU and
Debug:Show Keyboard dialog boxes.
The Debug:Show* dialog boxes are created by the ParamDialog class,
which already understands how to display each type of parameter,
including the new shadow parameters (because they are just a subclass
of a normal parameter class). I have added a ParamDialog::Refresh()
method, which rereads the value from every parameter that it is
displaying and changes the displayed value. At the moment, in the
Debug:Show CPU dialog, changing the values has no effect. However
this is trivial to add when it's time (just call CommitChanges!). It
wouldn't really make sense to change the values unless you have paused
the simulation, for example when single stepping with the debugger.
The Refresh() method must be called periodically or else the dialog
will show the initial values forever. At the moment, Refresh() is
called when the simulator sends an async event called
BX_ASYNC_EVT_REFRESH, created by a call to SIM->refresh_ci ().
Details:
- implement shadow parameter class for Bit32s, called bx_shadow_num_c.
implement shadow parameter class for Boolean, called bx_shadow_bool_c.
more to follow (I need one for every type!)
- now the simulator thread can request that the config interface refresh
its display. For now, the refresh event causes the CI to check every
parameter it is watching and change the display value. Later, it may
be worth the trouble to keep track of which parameters have actually
changed. Code in the simulator thread calls SIM->refresh_ci(), which
creates an async event called BX_ASYNC_EVT_REFRESH and sends it to
the config interface. When it arrives in the wxWindows gui thread,
it calls RefreshDialogs(), which calls the Refresh() method on any
dialogs that might need it.
- in the debugger, SIM->refresh_ci() is called before every prompt
is printed. Otherwise, the refresh would wait until the next
SIM->periodic(), which might be thousands of cycles. This way,
when you're single stepping, the dialogs update with every step.
- To improve performance, the CI has a flag (MyFrame::WantRefresh())
which tells whether it has any need for refresh events. If no
dialogs are showing that need refresh events, then no event is sent
between threads.
- add a few defaults to the param classes that affect the settings of
newly created parameters. When declaring a lot of params with
similar settings it's more compact to set the default for new params
rather than to change each one separately. default_text_format is
the printf format string for displaying numbers. default_base is
the default base for displaying numbers (0, 16, 2, etc.)
- I added to ParamDialog to make it able to display modeless dialog
boxes such as "Debug:Show CPU". The new Refresh() method queries
all the parameters for their current value and changes the value in
the wxWindows control. The ParamDialog class still needs a little
work; for example, if it's modal it should have Cancel/Ok buttons,
but if it's going to be modeless it should maybe have Apply (commit
any changes) and Close.
added --enable-repeat-speedups with default to disabled.
Reconfigure/recompile and the speedup code will be #ifdef'd
out for now. It manifested as junk written to the VGA screen
while booting/running Windows.
Also made some more mods to the main cpu loop. Moved the
handling of EXT/errorno outside the main loop, much like
the extra EIP/ESP commits were moved, for a little better
performance.
I changed the fetch_ptr/bytesleft method of fetching to
a slightly different model, which calculates a window
for which EIP will be valid (land on the current page),
and a bias which when applied to EIP will be from
0..upper_page_limit. Speed is about the same for either
method, but a pseudo-op/threaded-interpreter will plug
in better with this and be faster.
BX_SUPPORT_APIC were used. To follow the pattern used by other
names like this, I changed them all to BX_SUPPORT_APIC.
Thanks to Tom Lindström for chasing this down!
tries to fix it. The shortcuts to register names such as AX and DL are
#defines in cpu/cpu.h, and they are defined in terms of BX_CPU_THIS_PTR.
When BX_USE_CPU_SMF=1, this works fine. (This is what bochs used for
a long time, and nobody used the SMF=0 mode at all.) To make SMP bochs
work, I had to get SMF=0 mode working for the CPU so that there could
be an array of cpus.
When SMF=0 for the CPU, BX_CPU_THIS_PTR is defined to be "this->" which
only works within methods of BX_CPU_C. Code outside of BX_CPU_C must
reference BX_CPU(num) instead.
- to try to enforce the correct use of AL/AX/DL/etc. shortcuts, they are
now only #defined when "NEED_CPU_REG_SHORTCUTS" is #defined. This is
only done in the cpu/*.cc code.
in BRANCH-smp-bochs revisions.
- The general task was to make multiple CPU's which communicate
through their APICs. So instead of BX_CPU and BX_MEM, we now have
BX_CPU(x) and BX_MEM(y). For an SMP simulation you have several
processors in a shared memory space, so there might be processors
BX_CPU(0..3) but only one memory space BX_MEM(0). For cosimulation,
you could have BX_CPU(0) with BX_MEM(0), then BX_CPU(1) with
BX_MEM(1). WARNING: Cosimulation is almost certainly broken by the
SMP changes.
- to simulate multiple CPUs, you have to give each CPU time to execute
in turn. This is currently implemented using debugger guards. The
cpu loop steps one CPU for a few instructions, then steps the
next CPU for a few instructions, etc.
- there is some limited support in the debugger for two CPUs, for
example printing information from each CPU when single stepping.
