c_load.htm

mips架构的bootloader,99左右的版本 但源代码现在没人更新了

<title>The load Command</title>
<h1>load</h1>


<!--INDEX "load command" download hostport -->

The load command downloads programs and data from the host. <p>

</dl><h2>Format</h2><dl><dd>

The format for the load command is:<p>

<pre>
load [-abeistB] [-baud] [offset] [-c cmdstr] <i>filename</i>
</pre>

where:<p>

<table><tr><td>
-m	</td><td>Only load the symbol information.
</td></tr><tr><td>
-a	</td><td>suppresses addition of an offset to symbols.
</td></tr><tr><td>
-b	</td><td>suppresses deletion of all breakpoints before the download. 
</td></tr><tr><td>
-e	</td><td>suppresses clearing of the exception handlers.
</td></tr><tr><td>
-i	</td><td>ignores checksum errors.
</td></tr><tr><td>
-s	</td><td>suppresses clearing of the symbol table before the download.
</td></tr><tr><td>
-t	</td><td>loads at the top of memory (PMON only).
</td></tr><tr><td>
-f	</td><td>load driver from flash (IMON only).
</td></tr><tr><td>
-B	</td><td>Interprets input from host as binary data for Ethernet 
	transfers.
</td></tr><tr><td>
-baud		</td><td>sets the baud rate for transfer.
</td></tr><tr><td>
offset		</td><td>loads at the specified offset.
</td></tr><tr><td valign=top>
-c cmdstr	</td><td>sets a command string that the <a href="mondef.htm">Monitor</a> sends to the host to 
		start a download operation. String cmdstr is the string that 
		starts the download. Note that the command string must be 
		enclosed in double quotation marks if the string contains any 
		spaces.
</td></tr><tr><td>
filename	</td><td>load the specified file (imon95 only).
</td></tr></table><p>

Invoking the load command with no parameters or arguments clears the 
symbol table, deletes all current breakpoints, allows the <a href="mondef.htm">Monitor</a> to receive 
programs or data from the host, and uses the current baud rate by default.<p>

</dl><h2>Functional Description</h2><dl><dd>

The load command accepts programs and data from the host port in LSI
Logic's proprietary <a href="frec.htm">FastLoad format</a>, <a
href="srec.htm">Motorola S-record</a>, or binary files.  The user can
set environment variables to change the data port, the format, and the
transfer protocol. <p>

The load command normally clears the symbol table, exception handlers, 
and all breakpoints. The -s and -b options suppress the clearing of the 
symbol table and breakpoints, respectively. The value of the EPC register 
is set automatically to the entry point of the program. Therefore, to execute 
the downloaded program, only the g command is required.<p>

The -c option permits a command string to be sent to the host when the 
load command is issued. This is intended for use in conjunction with the 
transparent mode. Note that if the command string contains multiple 
words, the command must be enclosed in double quotation marks, as 
shown in the example below.<p>

The load command returns the error message "out of memory" if there is 
insufficient space in the heap for the program's global symbols. To 
increase the size of the heap , use the set heaptop command to reserve 
more space in the heap, and then use the -T option with the pmcc command 
to set the start address of the text section to the same address that was 
specified for the heap. See the pmcc command on page 3-13.<p>

</dl><h2>The dlecho, dlproto, and hostport Variables</h2><dl><dd>

The dlecho, dlproto, and hostport variables control operation of the 
download. The following table shows how these environment variables affect the 
operation of the load command.<p>

<center><table border cellpadding=5>
<tr><th align=left>Variable</th><th align=left>Action</th></tr>
<tr><td>dlecho off</td><td>Do not echo the lines</td></tr>
<tr><td>dlecho on</td><td>Echo the lines</td></tr>
<tr><td>dlecho lfeed</td><td>Echo only a linefeed for each line</td></tr>
<tr><td>dlproto none</td><td>Do not use a protocol</td></tr>
<tr><td>dlproto XonXoff</td><td>Send Xon and Xoff to control the host</td></tr>
<tr><td>dlproto EtxAck</td><td>Expect Etx as end of record, send Ack</td></tr>
<tr><td>hostport tty0</td><td>Select tty0 as the port to which the host is connected</td></tr>
<tr><td>hostport tty1</td><td>Select tty1 as the port to which the host is connected</td></tr>
<tr><td>hostport ethernet</td><td>Select <a href="dlether.htm">ethernet</a>
as the port to which the host is connected</td></tr>
</table></center><p>




See the section on downloading beginning on page 1-9 for more 
information on these variables and the use of the load command.<p>

</dl><h2>Examples</h2><dl><dd>

Download to tty1 using the <a href="tools/edown.htm">edown</a> program.<p>
<pre>
	PMON> set dlecho off 
	PMON> set hostport tty1 
	PMON> set dlproto EtxAck 
	PMON> load 	
	% edown < test1.rec
	Downloading from tty0, ^C to abort
	Entry address is 80020000

	Total = 0x00043C00 bytes
	PMON>
</pre><p>

Download to tty0 using a terminal emulator.<p>
<pre>
	PMON> set dlecho off 
	PMON> set hostport tty0 
	PMON> set dlproto none 
	PMON> load 	
	-- use terminal emulator's "send text file" command
	Downloading from tty0, ^C to abort
	Entry address is 80020000

	Total = 0x00043C00 bytes
	PMON>
</pre><p>

When using the <a href="mondef.htm">Monitor</a> in an environment where
tty1 is connected to a login line on a Unix host. You will need to send
a command to start the download. In the following example the command
"<samp>cat test1.rec</samp>" is sent to the host.<p>

<pre>
	PMON> load -c "cat test1.rec"
</pre><p>

</dl><h2>Files</h2><dl><dd>
The code for the load command is located in 
<a href="../pmon/load.c">pmon/load.c</a> (PMON), 
and <a href="../imon/load.c">imon/load.c</a> (IMON).

</dl><h2>See Also</h2><dl><dd>
<a href="c_set.htm">set</a> command for the setup 
of the environment variables.

</dl><p><hr>
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