 |
Index for
Section 1 |
|
 |
Alphabetical
listing for M |
|
 |
Bottom of
page |
|
mxr(1)
NAME
mxr - DECmigrate: MIPS Translator Runtime Environment
SYNOPSIS
[executable_name] [options...]
/usr/bin/mxr -help
/usr/bin/mxr -V
OPTIONS
-help
Display the mxr help message.
-V Display the mxr version number.
DESCRIPTION
The MIPS Translator Runtime Environment, mxr, supports binary executables
produced by DECmigrate (mx). When you execute the output executable on an
Alpha system running Tru64 UNIX, mxr is automatically invoked either as a
shared image or as a shared library. The mxr environment provides the
translated executable with any MIPS or ULTRIX resources it requires to run.
In cases where there is no Tru64 UNIX translation for an ULTRIX operation,
mxr supports the executable by emulating that operation. In addition, mxr
provides feedback, enabling mx to retranslate the executable, eliminate
some or all instances of emulation, and improve run-time performance.
RESTRICTIONS
The mxr environment does not support certain ULTRIX operations. See the
release notes for the unsupported ULTRIX operation. The mxr environment
only supports executables that were translated by mx.
The mxr environment only supports setuid or setgid programs or OMAGIC
executions if the executable was translated using the -coff option (the
default) to the mx command. In addition, mxr only supports non-finite
numbers if the executable was translated with the -full_fp option to the mx
command.
DEBUGGING
This section describes situations when the translated executable fails at
runtime, runs but produces different results than the original executable,
or runs slowly.
If an executable runs properly on an ULTRIX system but fails when
translated and run on a Tru64 UNIX system, check the following:
· File Names: Some executables read the name with which they were
invoked to determine operating behavior. To enable these executables
to run properly on a Tru64 UNIX system, ensure that the file names
match the original names of the files on the ULTRIX system. Restore
filenames as necessary.
· Missing Files: See if there are any files that need to be moved to the
Tru64 UNIX system. Some executables require certain files to exist at
specific places in the file system, and fail when that is not true.
For example, many X clients require files in /usr/lib/X11/app-defaults
and /usr/lib/X11/uid. Translated MicroFocus COBOL programs attempt to
access the file /usr/lib/cobol/rts32, and abort if that file is not
present.
To see a list of the files that a program is trying to find, set the
environment variable MXR_TRACE_VARIABLES to stat,open.
To run translated programs, copy the missing files to the Tru64 UNIX
system and place them in directories that correspond to their original
directories. For example, to run translated MicroFocus COBOL programs
on a Tru64 UNIX system, do the following:
1.
On the Tru64 UNIX system, create the /usr/lib/cobol directory.
2.
Copy the /usr/lib/cobol/rts32 file from the ULTRIX system on which
COBOL is installed to the /usr/lib/cobol directory on the Tru64 UNIX
system.
3.
Invoke the translated executable.
· Floating Point Exceptions: Floating point calculations involving
non-finite numbers such as infinites, denormalized numbers, or Not-a-
Numbers (NaNs), generate exceptions on the Alpha architecture. These
calculations are handled silently by the MIPS architecture. If an
executable generates SIGFPEs, an error message of the following form
displays and the program terminates:
The translated program attempted
a floating-point calculation with
a denormalized number or NaN.
Retranslate using the -full_fp option
to mx.
To reproduce the MIPS system behavior, mxr must intercept these
exceptions and perform the appropriate actions without signaling the
translated program. Retranslate program using the -full_fp option to
mx, then run the new translated executable. The results of the
calculations using or producing non-finite numbers are consistent with
IEEE/ANSI 754-1985 and should produce the same results as the original
program. See the user manual for more information. If the executable
still generates SIGFPEs, try translating with the mx option -trapb. If
you do this, please file an SPR including the results with Compaq so
that -full_fp option can be enhanced. You can still use
MXR_GENERATE_FEEDBACK, but -full_fp must be set each time you
retranslate the executable. See the FEEDBACK section.
· Error message saying "Unaligned access on ldt" or "Unaligned access on
stt:" If you get a message of this form, retranslate using the -F
option to mx. This causes mx to assume that all floating-point loads
and stores are potentially unaligned, and to generate code
accordingly. Refer to the EXAMPLES section.
· Error message saying "Stack not longword aligned:" This error message
indicates a serious bug in your original program.
If an executable runs on the Tru64 UNIX system but does not produce
the same output as the ULTRIX executable, check the following:
1.
Some executables look at the stack and use the return address to
examine the MIPS code stream. These executables will not work
properly when translated. These executables include:
--
Ada executables that use exceptions
--
PL/1 executables that use signals
--
Some classes of FORTRAN executables
--
Some programs that use Compaq's VMS portability library (plib).
2.
Some executables expect non-finite, floating point numbers, such as
infinities, denormalized numbers, and Not-a-Numbers, to behave as
specified in the IEEE/ANSI 754-1985 standard. To support this, you
must translate the executable with the -full_fp option. Otherwise,
the results of the translated executable might be different from the
original executable, or may abort with a floating-point exception.
· Error message saying "The program changes the rounding mode to
-Infinity..." Retranslate the executable using the -fixround option.
At runtime, code checks the rounding mode, and changes each instance
of floating point rounding to RM (minus infinity) to floating point
rounding to RZ (zero).
This may cause a slight loss of precision, but might substantially
improve the runtime performance of the translated program.
· The /bin/time file created by the executable shows large amounts of
time being spent on system operations. Translate executable using the
-fixround option. At runtime, code checks the rounding mode, and
changes each instance of floating point rounding to minus infinity
(RM) to floating point rounding to zero (RZ).
This may cause a slight loss of precision, but might substantially
improve the runtime performance of the translated program.
If the translated executable runs, but slowly, see if the translation
can be improved with feedback. See the FEEDBACK section.
FEEDBACK
If you set the MXR_GENERATE_FEEDBACK environment variable and the
executable creates or extends a .hif file when executing, this means mxr
discovered new entry points while executing the executable. Retranslating
the executable allows mx to access the entry points and improve the speed
of the executable. Do the following:
1. Delete or remove the translated executable. You do not need it to
create the next version.
2. Copy only the .hif file to the system and directory containing both mx
and the original input executable. Be sure the name of the .hif file
is executable.hif, where executable is the file name of the input
executable.
3. Retranslate the original input executable using mx.
The mx translator reads the .hif file and uses the information in it
to improve the translation.
4. Run the retranslated executable with the MXR_GENERATE_FEEDBACK
environment variable set.
5. If the retranslated executable discovers more entry points, it appends
entries to the .hif file, extending the file. Repeat steps 1, 2, 3,
and 4 until no new .hif entries are created during execution.
ERROR MESSAGES
Error messages are described in the DECmigrate User's Guide.
The severity levels are as follows:
INFO
Informational message. Not displayed unless MXR_VERBOSE is set.
WARNING
Warning message. Warning messages are displayed unless MXR_QUIET is
set. A warning usually results in the specified operation, such as
syscall, returning an error status, but the translated program
continues to run.
ERROR
Fatal error message. Always displayed if an error occurs. Error
messages cause immediate termination of the translated program.
ENVIRONMENT VARIABLES
The mxr environment modifies its behavior if any of the following
environment variables are set when you execute a translated executable:
MXR_GENERATE_FEEDBACK
Generate a .hif file to use as feedback for a subsequent retranslation.
This is overridden by the -nohifs option in mx. See the FEEDBACK
section.
MXR_XTERM
Redirect mxr input/output through an xterm window. This is useful for
separating mxr diagnostic messages.
MXR_VERBOSE n
Print all debugging output in detailed form.
1 Prints program header information and "unrecognized error tag"
messages.
2 Prints program load/execute progress.
3 Prints program exit details and homing map.
7 Prints signal details.
8 Prints ioctl() details.
9 Prints brk() details.
10 Prints computed branch details.
MXR_QUIET
Suppress all mxr output except for fatal errors. Note: You may be
suppressing nonfatal error messages that indicate you are using an
unsupported feature. The executable still runs, but its function is
unpredictable.
MXR_TRACE_SYSCALLS xxx,xxx
Trace all system calls. If no system calls are specified, all system
calls are traced. If any system calls are specified or if the word
"all" appears in the list, only those calls are traced. Preceding a
system call name with a hyphen (-) forces it not to be traced. The list
is scanned left-to-right. Separate the system call names with commas
(,). For example:
MXR_TRACE_SYSCALLS open, close, read, write
Traces the calls specified.
MXR_TRACE_SYSCALLS all, -read, -write
Traces all syscalls except read and write. If you are using either the
ksh or sh shell, the format is:
MXR_TRACE_SYSCALLS=xxx,xxx
export MXR_TRACE_SYSCALLS
MXR_STATS_DISPLAY
Display runtime statistics when the executable exits.
MXR_TRACE_SIGNALS
Trace all signals and signal system calls.
EXAMPLES
The following is an excerpt from the terminal output of an executable that
needs to be retranslated by mx with the -F option. The opcodes stt
(type=stt) and ldt (type=ldt) are the ones in error.
[963] piston:person> dxpsview quilt.ps
Unaligned access pid=419 <mxr> va=10041624 reg=4 type=stt pc=58cbd8 ra=58c8f0
Unaligned access pid=419 <mxr> va=1004161c reg=2 type=ldt pc=58cbd8 ra=58c8f0
FILES
/usr/shlib/mxr.so
The run-time support for executables translated using the -coff option
to the mx command. Resides on the Tru64 UNIX system, and called in as
a shared library by the translated executable.
/usr/bin/mxr
The runtime support for executables translated using the -script option
in mx.
mx.out
The default name of the translated output file.
SEE ALSO
DECmigrate User's Guide
|
Index for
Section 1 |
|
|
Alphabetical
listing for M |
|
 |
Top of
page |
|