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The complete tool name is a three-part hyphenated string.
The first part indicates the processor or processor family (mn10300).
The second part indicates the file format output by the tool (elf).
The third part is the generic tool name (gcc).
For example, the GCC compiler for the Matsushita MN10300 is,
mn10300-elf-gcc.
The MN10300 package includes the following supported tools:
Tool Description | Tool Name |
GCC compiler | mn10300-elf-gcc |
C++ compiler | mn10300-elf-c++ |
GAS assembler | mn10300-elf-as |
GLD linker | mn10300-elf-ld |
Standalone simulator | mn10300-elf-run |
Binary Utilities | mn10300-elf-ar
mn10300-elf-nm mn10300-elf-objcopy mn10300-elf-objdump mn10300-elf-ranlib mn10300-elf-size mn10300-elf-strings mn10300-elf-strip |
GDB debugger | mn10300-elf-gdb |
MN10300 Series evaluation board.
Both targets run in little-endian mode.
CPU | Operating System | Vendor |
x86 | Windows NT 4.0 | Microsoft |
x86 | Redhat Linux 5.x | Redhat |
C:\cygnus\gnupro\i386-cygwin32\mn10300-elf\ecos-98r1p6
For Bourne shell compatible shells:
if ( "$?MANPATH" == "0"
) then
setenv MANPATH "/usr/local/man:/usr/man"
endif
if ( "$?INFOPATH" ==
"0" ) then
setenv INFOPATH "/usr/local/info:/usr/info"
endif
setenv MANPATH $PROOT/man:$MANPATH
setenv INFOPATH $PROOT/info:$INFOPATH
set path = ( $PROOT/H-i386-pc-linux-gnu/bin
$path )
-mmult-bug
static object_t myobj __attribute__((init_priority (30000) ));
The syntax is slightly different if the object takes any arguments to its constructor:
static object_t myobj __attribute__((init_priority (30000) )) = object_t(arg1, arg2);
The numeric priority can be from 1 to 65535, with 1 being the highest priority, and 65535 being the lowest. The default priority for objects without this attribute is 65535. Constructors with a higher priority are guaranteed execution before constructors with lower priority.
In all cases, you must provide the argument -finit-priority to the compiler on its command-line for it to recognize this attribute when you are compiling your C++ source files.
If you are using eCos, be warned that eCos uses initialization
priorities internally. Ensure you choose an appropriate priority level
so that other eCos subsystems will have initialized before you refer to
them in your own constructor.
The GNUPro C and C++ compilers can now optionally remove these unnecessary functions from the final image. They also ensure that any shared global data is removed that is only referenced by functions that are removed. This can be done by including the options -ffunction-sections and -fdata-sections on the command-line, when you invoke the C or C++ compiler. The -ffunction-sections option removes unnecessary functions, and the -fdata-sections option removes unnecessary data.
In addition, when classes define virtual methods in C++, it is possible to remove any unused methods from the final image by passing the option -fvtable-gc to the C++ compiler on its command-line.
In all cases, you must also supply a command-line option
when linking. If invoking the linker ld directly, use --gc-sections
on its command-line; alternatively, if you are using the preferred method
of linking your executable, using the form
gcc
-o <program name> <file1>.o <file2>.o,
then also pass the option -Wl,--gc-sections
on the compiler command-line, for example:
Type | Size (bytes) | Alignment (bytes) |
char | 1 byte | 1 byte |
short | 2 bytes | 2 bytes |
int | 4 bytes | 4 bytes |
long | 4 bytes | 4 bytes |
long long | 8 bytes | 8 bytes |
float | 4 bytes | 4 bytes |
double | 8 bytes | 8 bytes |
long double | 8 bytes | 8 bytes |
pointer | 4 bytes | 4 bytes |
Type | Registers | Notes |
volatile | d0, d1, a0, a1 | |
saved | d2, d3, a2, a3 | |
special purpose | sp, ccr, mdr, lar, lir | (1) (2) |
frame pointer | a3 (if needed) | (3) |
Stack frames for functions that take a variable number of arguments look like:
Any argument, more than 8 bytes in size, is passed by invisible reference. The callee is responsible for copying the argument if the callee modifies the argument.
d0 and d1 are used for returning other scalars and structures less than or equal to 8 bytes in length.
If a function returns a structure that is greater than 8 bytes in length, then the caller is responsible for passing in a pointer to the callee which specifies a location for the callee to store the return value. This pointer is passed as the first argument word before any of the functions declared parameters.
The assembler does not support "user defined instructions" nor does it support synthesized instructions (pseudo instructions, which correspond to two or more actual machine instructions).
Register Direct: | |
Dm/Dn | |
Am/An | |
Immediate value: | |
imm8/regs | |
imm16 | |
imm32 | |
imm40 | |
imm48 | |
Register Indirect: | |
(Am)/(An) | |
Register indirect with displacement | |
(d8,Am)/(d8,An) | d8 is sign extended |
(d16,Am)/(d16,An) | d16 is sign extended |
(d32,Am)/(d32,An) | |
(d8,pc) | d8 is sign extended |
(d16,pc) | d16 is sign extended |
(d32,pc) | |
(d8,sp) | d8 is sign extended |
(d16,sp) | d16 is sign extended |
(d32,sp) | |
Absolute: | |
(abs16) | abs16 is zero extended |
(abs32) | |
Register indirect with index | |
(Di,Am)/(Di,An) |
For detailed information, see MN10300 Series Instruction Manual.
There are two ways for GDB to talk to an MN10300 target. Each target requires that the program be compiled with a target specific linker script.
Note:
Loading binaries into the simulator that were built for
the standard evaluation board with RAM startup will not work.
To activate the simulator in GDB, follow the instructions
in the Simulator section later in this document.
target remote <devicename>
where <devicename> will be a serial device such as com2 (Windows NT) or /dev/ttyS1 (Linux). Then load the code onto the target board by typing load. After being downloaded, the program can be executed.
In some operating systems, such as eCos, a single program may have more than one thread of execution. The precise semantics of threads differ from one operating system to another, but in general the threads of a single program are akin to multiple processes, except that they share one address space (that is, they can all examine and modify the same variables). On the other hand, each thread has its own registers and execution stack, and perhaps private memory.
GDB provides the following functions for debugging multi-thread programs
info threads
When your program has multiple threads, you can choose
whether to set breakpoints on all threads, or on a particular thread.
If you do not specify thread <threadno> when you set a breakpoint, the breakpoint applies to all threads of your program.
You can use the thread qualifier on conditional breakpoints
as well; in this case, place thread
<threadno> before the breakpoint
condition, as the following example shows.
Conversely, whenever you restart the program, all threads start executing. This is true even when single stepping with commands like step or next. In particular, GDB cannot single-step all threads in lockstep. Since thread scheduling is up to your debugging targets operating system (not controlled by GDB), other threads may execute more than one statement while the current thread completes a single step. In general other threads stop in the middle of a statement, rather than at a clean statement boundary, when the program stops.
You might even find your program stopped in another thread
after continuing or even single stepping. This happens whenever some other
thread runs into a breakpoint, a signal, or an exception before the first
thread completes whatever you requested.
Normally GDB does not attempt to interfere with thread scheduling. This means that in the default mode (scheduler-locking off), the current thread may be scheduled out, and a different thread may begin running, at any time (as determined by the native scheduler). For instance, you may give a GDB command such as step or finish, and when the command completes, you may be looking at a different thread.
If you set the scheduler-locking mode to step, then GDB will try to interfere with the native scheduler just enough to prevent another thread from popping up while you debug. Other threads may get to run sometimes, but whenever a command such as step or finish completes, you should be looking at the same thread that was running before the command. Of course, if another thread gets to run and hits a breakpoint, GDB will still switch you to that thread (so if you dont want that to happen, then disable your breakpoints).
For even greater (and more intrusive) control over the thread scheduler, GDB provides the mode scheduler-locking on. In this mode, the native scheduler is completely locked, and no thread may run except the current one. Obviously this will radically change the behavior of your program, and may lead to deadlock or other unpleasant consequences, so use it with caution.
Syntax:
set scheduler-locking [off on step]
The MN10300 simulator is not designed to match timing characteristics of its target board. For example, the CPU module uses a single clock cycle for all instructions, its memory is infinitely fast, and its simulated serial I/O is infinitely fast. Furthermore, a number of obscure or inapplicable functions were omitted from the simulated peripherals. The simulator is just complex and accurate enough to run eCos programs.
Volatile registers: d0, d1, a0, a1
Saved registers: d2, d3, a2, a3
Special purpose registers: sp, pc, ccr, mdr, lar, lir
Memory is 4mb starting at location 0x48000000. The stack starts at the highest memory address and works downward. The heap starts at the lowest address after the text, data and bss.
--board=BOARD
Here are the first 10 lines of the file produced by the above run:
2 a0040004 ; width
4 ; load instruction
2 a0040008 ; width
4 ; load instruction
2 a004000c ; width
4 ; load instruction
2 a0040010 ; width
4 ; load instruction
2 a0040014 ; width
4 ; load instruction
2 a0040018 ; width
4 ; load instruction
2 a004001c ; width
4 ; load instruction
2 a0040020 ; width
4 ; load instruction
2 a0040024 ; width
4 ; load instruction
2 a0040028 ; width
4 ; load instruction
C:\> mn10300-elf-run
--trace --tracefile=trace.out hello
Placing trace information
into file "trace.out"
Hello, world!
3 + 4 = 7
HAL configuration, for various download methods
Download method | HAL configuration |
Burn hardware ROM | ROM startup |
Download to ROM emulator | ROM startup |
Download to board with CygMon | RAM startup |
Download to simulator without CygMon | ROM startup |
Download to simulator with CygMon | RAM startup |
Download to simulator, ignoring devices | SIM configuration |
In most circumstances, you should not download to simulator ignoring devices. If you use this download method, the binaries built with this configuration will not run on the target board; they can only run on the simulator. Likewise, binaries built to run on the target board will not run on the simulator.
In some cases, you may want to use a simulator specific configuration to try to work around problems with the device drivers or with the simulator itself.
Simulator clocks and timers sometimes appear to be running very slowly, even when there are apparently no active threads. Delays that should only be in seconds can run to minutes. These delays occur because the eCos kernel idle thread is running intensively, and the simulator emulates it faithfully. With the SIM configuration, however, the eCos kernel realizes it is in a simulated environment, and can therefore adjust the clock settings to be more realistic.
For example, suppose you are debugging a ROM monitor in the simulator invoked from GDB (well call this GDB1), and you have downloaded an application to it from a second GDB session (which we will call GDB2). The second GDB session, GDB2, would simply consider the simulated target as a remote target and nothing more. Now suppose that in GDB2 you set a breakpoint in the program. The breakpoint will be physically set in GDB1. So when the breakpoint is reached, instead of the breakpoint being handled by the ROM monitor as if it was a real target, the breakpoint will be interpreted by GDB1 as if you had asked GDB1 to set a breakpoint in the ROM monitor code. This may not be your desired intention. To solve this, you can tell GDB1 not to process breakpoints itself, but to let the simulated target process them.
To do this, use the following command:
For example the command handle SIGTRAP pass nostop noprint tells GDB to not stop the simulated target at a breakpoint, or even to print that it has been stopped. Instead, the command tells GDB to pass the information back to the program. You can modify the command to use with other signals and exceptions.
Note: if you use the aforementioned command, you will no longer be able to set breakpoints in the ROM monitor code (as in the example). You may be able to work around this problem by using conditional breakpoints. Please consult the GDB manual on how to use conditional-breakpoints.
The ambiguities discussed in this section are not a problem when you are using the standalone simulator. In such a case, the standalone simulator is the only target program that can handle the exception
While this approach offers the desired functionality, it is has a few disadvantages. The simulator is not only slow to execute code compared with real hardware, but simulation of the ROM monitor also slows the downloading of code to approximately the speed of a serial port. In addition, since the simulator must run continuously to execute CygMon, it can interfere with the performance of GDB. If there is insufficient memory for both programs to be in memory together, there may also be delays due to memory paging.
This technique uses TCP/IP for communication between the simulator and GDB, so you must ensure that the TCP/IP protocol stack is installed on your machine.
To run CygMon in the simulator, type the following command at the command line:
mn10300-elf-run --board=stdeval1 --sockser-addr=localhost:XXXX cygmon.rom
Where XXXX, is an unused TCP port number on your computer. A value of 1234 usually works, but any number between 1024 and 65535, which does not result in an error will do. The executable, cygmon.rom can be found in the directory, loaders/mn10300-stdeval1 within the eCos installation.
This has started the simulator running CygMon. To make use of it you must run a separate GDB session and connect to it.
If you run GDB in command-line mode, you can attach it
to the simulated CygMon with the following command:
If you are running the GDBTk then, in the Target Settings dialog, select Remote/TCP in the Target edit field. Type localhost into the Host edit field, and put the value chosen for the port number in the Port entry.
You should use executables configured to run on the target board with RAM startup, and not executables configured for the simulator.
If the performance of the two programs on a single machine
is too slow, it is possible to use two machines: one to run the simulator
and one to run GDB. These machines must be connected together on a TCP/IP
network. Run the simulator on one machine, but supply the name of the machine
in place of localhost
in the --sockser-addr
option. When running GDB on the other machine, replace localhost
with the name of the machine running the simulator.
CygMon has basic program handling and debugging commands, programs can be loaded into memory and run, and the contents of memory can be viewed. There are several more advanced options that can be included at compile time, such as a disassembler (this of course increases the code size significantly).
Since CygMon contains a GDB remote stub, full debugging can be done from a host running GDB to a target running CygMon. Switching between CygMon monitor mode and GDB stub mode is designed to be transparent to the user, since CygMon can detect when GDB is communicating with the target and switch into stub mode. When GDB stops communicating with the target normally, it sends a termination packet which lets the stub know when to switch to the CygMon monitor mode.
The command parser was written specifically for CygMon, to provide necessary functionality in limited space. All commands consist of words followed by arguments separated by spaces. Abbreviations of command names may be used. Any unique subset of a command name is recognized as being that command, so du is recognized to be the dump command. The user is prompted to resolve any ambiguities. Generally, a command with some or all of its arguments empty will either assume a default-set of arguments or return the status of the operation controlled by the command.
CygMon includes an API, which allows user programs, running under it, to use system calls for various functions. The available system calls allow access to the serial ports and on-board timer functions, if they are available.
For users of the Sourceware release of eCos, instructions can be found at
C:\Program Files\Cygnus Solutions\eCos\ecos-98r1p6\cygmon-src
If you choose to install the sources to a different location, the cygmon-src
directory will be located at ecos-98r1p6\cygmon-src
relative to the specified location. Please note that due to the configuration
and build tools being used, the sources must be installed in a directory
hierarchy that uses only alphanumeric, dash or underscore characters in
the directory names.
Programs->Cygnus eCos->eCos Development Environment
This will bring up a window running bash.
Mount the sources such that the full path to the CygMon
sources uses only alphanumeric, dash or underscore characters:
cygmon.rom
Is the ELF executable of the ROM-resident version of
CygMon. It is used in the standalone simulator for thread-aware debugging.
cygmon.sre
Is the ROM-resident version of CygMon in S-Record format.
If you want to read the source code, here are the names of the files
in the cygmon and libstub directories, specific to this version of CygMon.
File names | Descriptions | |
|
||
libstub/generic-stub.c | Generic remote debug stub | |
libstub/relocate.c | Segment relocation while booting ROMS | |
cygmon/bsp/monitor.c | Detailed vector table management | |
cygmon/bsp/monitor_cmd.c | Cygmon command interpreter | |
cygmon/bsp/ledit.c | CygMon line editor | |
|
||
libstub/mn10300/mn10300.mk | Makefile common to all MN10300 variants | |
libstub/mn10300/mn10300-stub.c | Specific to MN10300, gdb stub support | |
cygmon/mn10300/mn10300.mon.c | Specific to MN10300, CygMon support | |
|
||
libstub/mn10300/eval.mk | Makefile specific to MN10300 EVB | |
libstub/mn10300/mn10300-lib.c | Support for MN10300 EVB | |
cygmon/mn10300/mn10300.mon.ld | CygMon linker script for EVB |
The baud command sets the speed of the active serial port. It takes one argument, which specifies the speed to which the port will be set.
Example: baud 9600
Sets the speed of the active port to 9600 baud.
The break command displays and sets breakpoints in memory. It takes zero or one argument. With zero arguments, it displays a list of all currently set breakpoints. With one argument it sets a new breakpoint at the specified location.
Example: break 4ff5
Sets a breakpoint at address 4ff5.
The disassemble command disassembles the contents of memory. Because of the way breakpoints are handled, all instructions are shown and breakpoints are not visible in the disassembled code. The disassemble command takes zero or one argument. When called with zero arguments, it starts disassembling from the current (user program) pc. When called with a location, it starts disassembling from the specified location. When called after a previous call and with no arguments, it disassembles the next area of memory after the one previously disassembled.
Example: disassemble 45667000
Displays disassembled code starting at location 45667000.
The dump command shows a region of 16 bytes around the specified location, aligned to 16 bytes. Thus, dump 65 would show all bytes from 60 through 6f.
Example: dump 44f5
Displays 16 bytes starting with 44f0 and ending with 44ff.
The go command starts user program execution. It can take zero or one argument. If no argument is provided, go starts execution at the current pc. If an argument is specified, go sets the pc to that location, and then starts execution at that location.
Example: go 40020000
Sets the pc to 40020000, and starts program execution.
The help command without arguments shows a list of all available commands with a short description of each one. With a command name as an argument it shows usage for the command and a paragraph describing the command. Usage is shown as command name followed by names of extensions or arguments.
Arguments in [brackets]
are optional, plain text arguments are required. Note that all commands
can be invoked by typing enough of the command name to uniquely specify
the command. Some commands have aliases, which are
one-letter abbreviations for commands which do not have
unique first letters. Aliases for all commands are shown in the help screen,
which displays commands in the format:
command name: (alias, if any) description of command
Example: help foo
Shows the help screen for the command foo.
The load command switches the monitor into a state where it takes all input as s-records and stores them in memory. The monitor exits this mode when a termination record is hit, or certain errors (such as an invalid s-record) cause the load to fail.
The memory command is used to view and modify single locations in memory. It can take a size extension, which follows the command name or partial command name without a space, and is a period, followed by the number of bits to be viewed or modified. Options are 8, 16, 32, and 64. Without a size extension, the memory command defaults to displaying or changing 8 bits at a time.
The memory command can take one or two arguments, independent of whether a size extension is specified. With one argument, it displays the contents of the specified location. With two arguments, it replaces the contents of the specified location with the specified value.
Example: memory.8 45f6b2 57
Places the 8-bit value 57 at the location 45f6b2.
The port command allows control over the serial port being used by the monitor. It takes zero or one argument. Called with zero arguments it displays the port currently in use by the monitor. Called with one argument it switches the port in use by the monitor to the one specified. It then prints out a message on the new port to confirm the switch.
Example: port 1
Switches the port in use by the monitor to port 1.
The register command allows the viewing and manipulation of register contents. It can take zero, one, or two arguments. When called with zero arguments, the register command displays the values of all registers. When called with only the register name argument, it displays the contents of the specified register. When called with both a register name and a value, it places that value into the specified register.
Example: register g1 1f
Places the value 1f in the register g1.
The reset command resets the board.
The step command causes one instruction of the user program to execute, then returns control to the monitor. It can take zero or one argument. If no argument is provided, step executes one instruction at the current pc. If a location is specified, step executes one instruction at the specified location.
Example: step
Executes one instruction at the current pc.
The terminal command sets the type of the current terminal to that specified in the type argument. The only available terminal types are vt100 and dumb. This is used by the line editor to determine how to update the terminal display.
Example: terminal dumb
Sets the type of the current terminal to a dumb terminal.
The transfer or $ function transfers control to the gdb stub. This function does not actually need to be called by the user, as connecting to the board with gdb will call it automatically. The transfer command takes no arguments. The $ command does not wait for a return, but executes immediately. A telnet setup in line mode will require a return when executed by the user, as the host computer does not pass any characters to the monitor until a return is pressed. Disconnecting from the board in gdb automatically returns control to the monitor.
The unbreak command removes breakpoints from memory. It takes one argument, the location to remove the breakpoint from.
Example: unbreak 4ff5
Removes a previously set breakpoint at memory location 4ff5.
Shows the amount of memory being used by the monitor, broken down by category. Despite its name, it has nothing to do with the usage of any other command.
The version command displays the version of the monitor.
These are common EMACS and X text editing escape sequences. Here are the keys for editing.
Keystroke | Command |
CR \n | Execute the currently displayed command |
ctl-a | Move to Beginning of line |
ctl-e | End of line |
ctl-f | Forward char |
ctl-b | Backward char |
ctl-k | Delete to end of line |
ctl-y | Yank Character (undelete) |
ctl-d | Delete current character |
ctl-p | Edit previous command |
ctl-u | Erase Line |
ctl-n | Edit next command |
When developing and debugging CygMon, it is convenient
to run CygMon itself as a downloadable application. There are some modifications
that the developer may want to make temporarily, to debug CygMon. Reconfigure
CygMon so it does not patch the exception handler. Have your test program
call breakpoint explicitly. This combination disables CygMon in some serious
ways, but many essential features remain functional and debuggable. Breakpoints
can be administered, memory accesses can be tested, or registers fetched.
You can debug the serial driver. But, you cannot resume execution, single
step or test if a breakpoint has been hit. You can force CygMon through
its context-save and context-restore. This is the plan; get all the basics
working and verified, and then restore the exception patching capability.
MN103000 LSI Users Manual
(1st Edition, Matsushita Electronics Corporation, November, 1996)
32-bit Microcontroller MN103002A LSI Manual
(Version 3.0, Matsushita Electronics Corporation)
Getting Started with eCos version 1.2.1
(Sunnyvale: Cygnus Solutions, 1999)
eCos User's Guide version 1.2.1
(Sunnyvale: Cygnus Solutions, 1999)
eCos Reference Manual version 1.2.1
(Sunnyvale: Cygnus Solutions, 1999)
Getting Started with GNUPro Toolkit
(Sunnyvale: Cygnus Solutions, 1999)
GNUPro Compiler Tools
(Sunnyvale: Cygnus Solutions, 1999)
GNUPro Debugging Tools
(Sunnyvale: Cygnus Solutions, 1999)
GNUPro Libraries
(Sunnyvale: Cygnus Solutions, 1999)
GNUPro Utilities
(Sunnyvale: Cygnus Solutions, 1999)
GNUPro Advanced Topics
(Sunnyvale: Cygnus Solutions, 1999)
GNUPro Tools for Embedded Systems
(Sunnyvale: Cygnus Solutions, 1999)
System V Application Binary Interface
(Prentice Hall, 1990)