c_set.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 set Command</title>
<h1>set</h1>

<!--INDEX nvram inalpha environment dlecho dlproto hostport heaptop -->
<!--INDEX etheraddr inbase moresz prompt regstyle rptcmd trabort ulcr -->
<!--INDEX uleof datasz brkcmd validpc "set command" -->


The set command sets and displays environment variables.<p>

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

The format for this command is:<p>

<pre>
	set [<var>name</var> [<var>value</var>]]
	set nvram [<var>cmdlist</var>]
</pre>

where:<p>

<table><tr><td>
<var>name</var>	</td><td>is the name of the environment variable to set.

</td></tr><tr><td>
<var>value</var>	</td><td>is the string to which the environment variable is set.

</td></tr><tr><td>
nvram	</td><td>causes the environment 
variables and stty settings to be copied into NVRAM.

</td></tr><tr><td>
<var>cmdlist</var>	</td><td>is the list of  PROM <a href="mondef.htm">Monitor</a> commands to be executed 
following reset.  
</td></tr></table><p>

Entering the set command with no arguments displays all the current 
environment variables.<p>

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

The set command is used to set or display environment variable values, to 
copy the settings of environment variables and terminal options to 
NVRAM, and to specify a list of commands to be executed by the PROM 
<a href="mondef.htm">Monitor</a> following reset.  <p>

In some cases, when the <a href="mondef.htm">Monitor</a> displays a
variable's current value, the <a href="mondef.htm">Monitor</a> prints a
list of allowed values enclosed in square brackets; in other cases, no
list is shown. In general, when the value is a numeric value, or when
the value has an unlimited range of possible values, no list is shown.
<p>

The set command does not evaluate the specified value or check the 
specified value against a list of allowed values. Value checking is only 
performed when a command uses a variable. <p>

To set a variable to a multiple-word value, enclose the value in single or 
double quotation marks.  <p>

When used with the nvram option, the set command copies the current
settings of the environments variables and the terminal options as
specified in the stty command into NVRAM. The optional command list
permits the user to specify  PROM <a href="mondef.htm">Monitor</a>
commands that will be executed following reset.  This option requires
that the flash memories support sector erase.  <p>

To avoid reading the NVRAM during power-up, hold the console return 
key down while releasing reset. After repeating this process several times, 
you will see the following message:<p>

<pre>
Skip NVRAM read? (y/n)? >
</pre> <p>

If you type `y', the booting process will proceed without reading the 
NVRAM.  <p>

Examples illustrating the use of the set command follow.<p>
<pre>
	PMON> set	Display all current values.
	    brkcmd = "l @pc 1"
	    datasz = -b          [-b -h -w]
	   inalpha = hex         [hex symbol]
	    inbase = 16          [auto 8 10 16]
	    moresz = 10        
	  regstyle = sw          [hw sw]
	    rptcmd = trace       [off on trace]
	   trabort = ^K        
	     uleof = %         
	      ulcr = off         [off on]
	   validpc = "_ftext etext"
	   heaptop = 80020000  
	    dlecho = off         [off on lfeed]
	   dlproto = EtxAck      [none XonXoff EtxAck]
	  hostport = tty1      
	    prompt = "PMON> "
	 etheraddr = aa:bb:cc:00:00:00
	    ipaddr = 71.0.0.211
	      diag = 0           [N[:dev]]

	PMON> set moresz	Display current moresz.
	moresz = 10 

	PMON> set moresz 20	Set moresz to 20 decimal.
</pre><p>

Display current value of Cause Register and display all 
general-purpose registers: <p>

<pre>
	PMON> set brkcmd "l @epc 1;r cause;r"
</pre>


<b>Environment Variables and Default Values </b><p>

<p><table border cellpadding=5>
<tr><th>Environment Variable</th><th>Default Value</th><th>Options</th></tr>

<tr><td nowrap>
brkcmd
</td> <td nowrap>
"l @epc 1"
</td> <td nowrap>
command list
</td></tr>

<tr><td nowrap>
datasz
</td> <td nowrap>
-b
</td> <td nowrap>
[-b|-h|-w]
</td></tr>

<tr><td nowrap>
dlecho
</td> <td nowrap>
off
</td> <td nowrap>
[off|on|lfeed]
</td></tr>

<tr><td nowrap>
dlproto
</td> <td nowrap>
EtxAck
</td> <td nowrap>
[none|XonXoff|EtxAck]
</td></tr>

<tr><td nowrap>
etheraddr
</td> <td nowrap>
aa:bb:cc:00:00:00
</td> <td nowrap>
string
</td></tr>

<tr><td nowrap>
ipaddr
</td> <td nowrap>
71.0.0.211
</td> <td nowrap>
string
</td></tr>

<tr><td nowrap>
heaptop
</td> <td nowrap>
80020000
</td> <td nowrap>
string
</td></tr>

<tr><td nowrap>
hostport
</td> <td nowrap>
tty1
</td> <td nowrap>
tty0-9
</td></tr>

<tr><td nowrap>
inalpha
</td> <td nowrap>
hex
</td> <td nowrap>
hex symbol
</td></tr>

<tr><td nowrap>
inbase 
</td> <td nowrap>
16
</td> <td nowrap>
[auto|8|10|16]
</td></tr>

<tr><td nowrap>
moresz
</td> <td nowrap>
10
</td> <td nowrap>
0-n
</td></tr>

<tr><td nowrap>
prompt
</td> <td nowrap>
"PMON> "
</td> <td nowrap>
string
</td></tr>

<tr><td nowrap>
regstyle
</td> <td nowrap>
sw
</td> <td nowrap>
[hw|sw]
</td></tr>

<tr><td nowrap>
rptcmd
</td> <td nowrap>
trace
</td> <td nowrap>
[off|on|trace]
</td></tr>

<tr><td nowrap>
trabort
</td> <td nowrap>
^K
</td> <td nowrap>
char
</td></tr>

<tr><td nowrap>
ulcr
</td> <td nowrap>
off
</td> <td nowrap>
[off|on]
</td></tr>

<tr><td nowrap>
uleof
</td> <td nowrap>
off
</td> <td nowrap>
string
</td></tr>

<tr><td nowrap>
validpc
</td> <td nowrap>
"_ftext etext"
</td> <td nowrap>
string
</td></tr>

<tr><td nowrap>
diag
</td> <td nowrap>
0
</td> <td nowrap>
[N[:dev]]
</td></tr>


</table><p>



Environment variables can be set and displayed using the 
<a href="c_set.htm">set command</a>.<p>

Brief descriptions of each of the variables follow, together 
with references to their complete descriptions.<p>

<ul>
<li>    brkcmd - This variable specifies a sequence of <a href="mondef.htm">Monitor</a> commands
	that are executed when a breakpoint halts program execution. See the <a
	href="c_b.htm">b command</a>.<p>

<li>    datasz - This variable controls whether data is displayed in
	byte, half-word, or word groups. See the <a href="c_d.htm">d
	command</a>.<p>

<li>    dlecho - This variable controls whether the target board echoes
	on downloads. An entire line can be echoed, a single line-feed
	character can be echoed, or there can be no echo at all. See the <a
	href="c_load.htm">load</a> command and the section on 
	<a href="flwctl.htm">flow control</a>.<p>

<li>    dlproto - This variable selects the download protocol for
	transfers via RS-232C. The <a href="mondef.htm">Monitor</a> supports Xon/Xoff and EtxAck
	download protocols. See the <a href="c_load.htm">load</a> command
	and the section on
	<a href="flwctl.htm">flow control</a>.<p>

<li>    etheraddr - This variable specifies the hardware Ethernet
	address. See the <a href="c_load.htm">load</a> command and the
	section on downloading
	via <a href="dlether.htm">Ethernet</a>.<p>

<li>    ipaddr - This variable specifies the Internet Protocol
	address. See the <a href="c_load.htm">load</a> command and the
	section on downloading
	via <a href="dlether.htm">Ethernet</a>.<p>

<li>	heaptop - This variable specifies the highest allowable address in the 
	heap maintained by the PROM <a href="mondef.htm">Monitor</a>. See the 
	<a href="c_load.htm">load</a> command.  <p>

<li>    hostport - This variable selects whether tty0, tty1, or
	ethernet is the host port. See the <a href="c_load.htm">load</a>
	command and the section on 
	<a href="flwctl.htm">flow control</a>.<p>

<li>	inalpha - This variable selects whether strings starting with the ASCII 
	characters a, b, c, d, e, and f are interpreted as symbols or 
	hexadecimal numbers. See the <a href="c_sh.htm">sh</a> command.<p>

<li>	inbase - This variable selects the default input base for numeric 
	values. 
	Users can input octal, decimal, or hexadecimal numbers by changing 
	this variable. See the <a href="c_sh.htm">sh</a> command.<p>

<li>	moresz - This variable specifies how many lines to display during 
	screen-at-a-time display. See the <a href="c_more.htm">more</a> 
	command.<p>

<li>    prompt - This variable defines the <a href="mondef.htm">Monitor</a> 
	prompt. An example of using this command is when you need to
	set the prompt to "PMON> " for compatibility with a source-level
	debugger. To do this use the following commands.<p>

	<pre>
		IMON> set prompt "PMON> "
		IMON> set nvram
	</pre>

	This will set the prompt to "PMON> " (note the space) and save this
	new value in the non-volatile memory (if supported).<p>

<li>	regstyle - This variable defines whether hardware or software names 
	are displayed for the LR33000 registers in the l command. See the 
	<a href="c_l.htm">l command</a>.<p>

<li>	rptcmd - When this variable is set to "on," the previous command is 
	executed again when the user enters an empty line. See the 
	<a href="c_sh.htm">sh</a> command.<p>

<li>	trabort - This variable selects the character that terminates 
	transparent mode and returns the <a href="mondef.htm">Monitor</a> 
	to command mode. See 
	the <a href="c_tr.htm">tr</a> command.<p>

<li>	ulcr - This variable defines whether there is a carriage return 
	or both a carriage return and a linefeed character at the end of 
	the line during dumps. See the <a href="c_dump.htm">dump</a> 
	command.<p>

<li>    uleof - This variable specifies a string that is sent to
	the host after a dump to the target has completed. See the 
	<a href="c_dump.htm">dump</a> command.  <p>

<li>	validpc - This variable specifies the range of valid PC values during 
	program tracing. See the <a href="c_t.htm">trace</a> command.<p>

<li>	diag - This variable specifies the diagnostic level. zero is off,
	non-zero is on. Valid values are 0 thru 9. By default the
	diagnostic output is sent to the console. However, you may
	direct it to another port. For example,

<pre>
	PMON> set diag 2:/dev/tty1
</pre>

</ul>
</dl><p><hr>
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