mingw/info/gdb/MIPS-Embedded.html

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  19 <h4 class="subsection">MIPS Embedded</h4>
  20
  21    GDB can use the MIPS remote debugging protocol to talk to a
  22 MIPS board attached to a serial line.  This is available when
  23 you configure GDB with <code>--target=mips-idt-ecoff</code>.
  24
  25    <p>Use these GDB commands to specify the connection to your target board:
  26
  27      <dl>
  28 <dt><code>target mips </code><var>port</var><code></code>
  29      <dd>To run a program on the board, start up <code>gdb</code> with the
  30 name of your program as the argument.  To connect to the board, use the
  31 command <code>target mips </code><var>port</var><code></code>, where <var>port</var> is the name of
  32 the serial port connected to the board.  If the program has not already
  33 been downloaded to the board, you may use the <code>load</code> command to
  34 download it.  You can then use all the usual GDB commands.
  35
  36      <p>For example, this sequence connects to the target board through a serial
  37 port, and loads and runs a program called <var>prog</var> through the
  38 debugger:
  39
  40      <pre class="example">          host$ gdb <var>prog</var>
  41           GDB is free software and ...
  42           (gdb) target mips /dev/ttyb
  43           (gdb) load <var>prog</var>
  44           (gdb) run
  45           </pre>
  46
  47      <br><dt><code>target mips </code><var>hostname</var><code>:</code><var>portnumber</var><code></code>
  48      <dd>On some GDB host configurations, you can specify a TCP
  49 connection (for instance, to a serial line managed by a terminal
  50 concentrator) instead of a serial port, using the syntax
  51 <code></code><var>hostname</var><code>:</code><var>portnumber</var><code></code>.
  52
  53      <br><dt><code>target pmon </code><var>port</var><code></code>
  54      <dd>PMON ROM monitor.
  55
  56      <br><dt><code>target ddb </code><var>port</var><code></code>
  57      <dd>NEC's DDB variant of PMON for Vr4300.
  58
  59      <br><dt><code>target lsi </code><var>port</var><code></code>
  60      <dd>LSI variant of PMON.
  61
  62      <br><dt><code>target r3900 </code><var>dev</var><code></code>
  63      <dd>Densan DVE-R3900 ROM monitor for Toshiba R3900 Mips.
  64
  65      <br><dt><code>target array </code><var>dev</var><code></code>
  66      <dd>Array Tech LSI33K RAID controller board.
  67
  68    </dl>
  69
  70 GDB also supports these special commands for MIPS targets:
  71
  72      <dl>
  73 <dt><code>set processor </code><var>args</var><code></code>
  74      <dd><dt><code>show processor</code>
  75      <dd>Use the <code>set processor</code> command to set the type of MIPS
  76 processor when you want to access processor-type-specific registers.
  77 For example, <code>set processor </code><var>r3041</var><code></code> tells GDB
  78 to use the CPU registers appropriate for the 3041 chip.
  79 Use the <code>show processor</code> command to see what MIPS processor GDB
  80 is using.  Use the <code>info reg</code> command to see what registers
  81 GDB is using.
  82
  83      <br><dt><code>set mipsfpu double</code>
  84      <dd><dt><code>set mipsfpu single</code>
  85      <dd><dt><code>set mipsfpu none</code>
  86      <dd><dt><code>show mipsfpu</code>
  87      <dd>If your target board does not support the MIPS floating point
  88 coprocessor, you should use the command <code>set mipsfpu none</code> (if you
  89 need this, you may wish to put the command in your GDB init
  90 file).  This tells GDB how to find the return value of
  91 functions which return floating point values.  It also allows
  92 GDB to avoid saving the floating point registers when calling
  93 functions on the board.  If you are using a floating point coprocessor
  94 with only single precision floating point support, as on the <small>R4650</small>
  95 processor, use the command <code>set mipsfpu single</code>.  The default
  96 double precision floating point coprocessor may be selected using
  97 <code>set mipsfpu double</code>.
  98
  99      <p>In previous versions the only choices were double precision or no
 100 floating point, so <code>set mipsfpu on</code> will select double precision
 101 and <code>set mipsfpu off</code> will select no floating point.
 102
 103      <p>As usual, you can inquire about the <code>mipsfpu</code> variable with
 104 <code>show mipsfpu</code>.
 105
 106      <br><dt><code>set remotedebug </code><var>n</var><code></code>
 107      <dd><dt><code>show remotedebug</code>
 108      <dd>You can see some debugging information about communications with the board
 109 by setting the <code>remotedebug</code> variable.  If you set it to <code>1</code> using
 110 <code>set remotedebug 1</code>, every packet is displayed.  If you set it
 111 to <code>2</code>, every character is displayed.  You can check the current value
 112 at any time with the command <code>show remotedebug</code>.
 113
 114      <br><dt><code>set timeout </code><var>seconds</var><code></code>
 115      <dd><dt><code>set retransmit-timeout </code><var>seconds</var><code></code>
 116      <dd><dt><code>show timeout</code>
 117      <dd><dt><code>show retransmit-timeout</code>
 118      <dd>You can control the timeout used while waiting for a packet, in the MIPS
 119 remote protocol, with the <code>set timeout </code><var>seconds</var><code></code> command.  The
 120 default is 5 seconds.  Similarly, you can control the timeout used while
 121 waiting for an acknowledgement of a packet with the <code>set
 122 retransmit-timeout </code><var>seconds</var><code></code> command.  The default is 3 seconds.
 123 You can inspect both values with <code>show timeout</code> and <code>show
 124 retransmit-timeout</code>.  (These commands are <em>only</em> available when
 125 GDB is configured for <code>--target=mips-idt-ecoff</code>.)
 126
 127      <p>The timeout set by <code>set timeout</code> does not apply when GDB
 128 is waiting for your program to stop.  In that case, GDB waits
 129 forever because it has no way of knowing how long the program is going
 130 to run before stopping.
 131 </dl>
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