c_r.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 r Command</title>
<h1>r</h1>

<!--INDEX "r command" "display registers" "pseudo registers" -->


The r command sets or displays register values.<p>

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

The format for the r command is:<p>

<pre>
	r [reg|* [val|field val]]
</pre>

where:<p>

<dl><dd>
<table>
<tr><td valign=top width=100>
reg</td><td>is the name of the register or registers (specified by wildcard 
characters) to display or modify.
</td></tr><tr><td valign=top>
val</td><td>is the value to which the specified register or registers should 
be modified.
</td></tr><tr><td valign=top>
field val</td><td>is the value to which the specified field in the specified 
		register should be modified.
</td></tr><tr><td valign=top>
*	</td><td>displays the contents of all registers except floating-point 
	registers.
</td></tr><tr><td valign=top>

f*	</td><td>displays the contents of all floating-point registers.
</td></tr></table></dl><p>

Invoking the r command without any parameters or arguments displays a 
list of all the general-purpose registers. <p>

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

The r command sets or displays register values. The character and word
wildcards, "*" and "?", can be used in the register name. The '?'
character matches any single character, while the '*' character matches
any number of any characters. This command accepts both hardware and
software names. Examples illustrating the use of the r command
follow.<p>

<dl><dd><table>
<tr><td width=300><samp>
r 			</samp></td><td>Display all General-purpose registers.
</td></tr><tr><td> <samp>
r *			</samp></td><td>Display all register values.
</td></tr><tr><td> <samp>
r 8			</samp></td><td>Display $8 (t0).
</td></tr><tr><td> <samp>
r t0			</samp></td><td>Display t0 ($8).
</td></tr><tr><td> <samp>
r t*			</samp></td><td>Display t0 through t9.
</td></tr><tr><td> <samp>
r epc			</samp></td><td>Display EPC register.
</td></tr><tr><td> <samp>
r epc start		</samp></td><td>Set EPC register to the symbol start value.
</td></tr><tr><td> <samp>
r 4 45			</samp></td><td>Set register 4 to 45.
</td></tr><tr><td> <samp>
r t0 45			</samp></td><td>Set register t0 to 45.
</td></tr><tr><td> <samp>
r sr 0			</samp></td><td>Set SR to zero.
</td></tr><tr><td> <samp>
r sr bev 1		</samp></td><td>Set the BEV bit of SR to one.
</td></tr><tr><td> <samp>
r epc a0020000		</samp></td><td>Set EPC to a0020000.
</td></tr><tr><td> <samp>
r a			</samp></td><td>Display the value of pseudo
			register 'a'.
</td></tr><tr><td> <samp>
r ?			</samp></td><td>Display the value of all pseudo
				registers.
</td></tr></table></dl><p>

There are 26 pseudo registers (named a thru z). These can be referenced
in the same way as real registers, and are typically used to implement
complex breakpoint conditions (see the <a href="c_when.htm">when</a>
command).<p>

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


Display all General Purpose registers.<p>
<pre>
PMON> r 
       zero      at       v0       v1       a0       a1       a2       a3 
 $0- 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
        t0       t1       t2       t3       t4       t5       t6       t7 
 $8- 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
        s0       s1       s2       s3       s4       s5       s6       s7 
$16- 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
        t8       t9       k0       k1       gp       sp       s8      ra 
$24- 00000000 00000000 00000000 00000000 00000000 80008b40 00000000 00000000
</pre>


Display all registers.  Note that the actual registers that are
displayed by the "<samp>r *</samp>" command depends on what type of
processor you are using. This display was generated using a LR33000.<p>

<pre>
PMON> r * 
 $0- 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
 $8- 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
$16- 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 
$24- 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

C0_EPC=a0020000 C0_BADADDR=00000000 C0_BPC=00000000 C0_BDA=00000000 
M_TIC1=000000 M_TIC2=000000 M_RTIC=025 
   C0_SR:  CU BEV TS PE CM PZ SWC ISC  IM&SW  KUo IEo KUp IEp KUc IEc 
          0000 0   0  0  0  0  0   0  00000000 0   0   0   0   0   0 
C0_CAUSE: BD CE   IP   SW EXCODE
           0  0 000000 00   Int 
C0_PRID: IMP Rev 
          0   0 
C0_DCIC: TR UD KD TE DW DR DAE PCE DE D I T W R DA PC DG 
          0  0  0  0  0  0  0   0   0 0 0 0 0 0  0  0  0 
  M_CFG: ICD DCD IBS DBS IW IOWAIT PW PWAIT CS PE DGE BFD RGN RPC CL DCE
          0   0   16  16  0    6    0    6   0  0  1   0   1   1   1   1
  M_TC1: CE IE INT 
          0  0  0 
  M_TC2: CE IE INT 
          0  0  0 
</pre>

Set the IEC bit of the Status Register.<p>

<pre>
PMON> r sr iec 1
</pre>

Display the Status Register.<p>

<pre>
PMON> r sr
  C0_SR: CU BEV TS PE CM PZ SWC ISC IM&SW  KUo IEo KUp IEp KUc IEc
        0000 1   0  0  0  0  0   0 00000000 0   0   0   0   0   1 
</pre><p>

You can use the <a href="c_ls.htm">ls</a> command to display the Status 
Register as a hex value. This technique can be used for any register.<p>

<pre>
PMON> ls -v @sr
0x00400001 = 0t4194305 = 0o20000001
</pre>

</dl><h2>Files</h2><dl><dd>
The r command is located in <a href="../mon/regs.c">mon/regs.c</a>.

</dl><h2>See Also</h2><dl><dd>
<a href="c_l.htm">l command</a>
for disassembling instructions from memory.

</dl><p><hr>
<b>Navigation:</b> 
<a href="index.htm">Document Home</a> | 
<a href="doctoc.htm">Document Contents</a> | 
<a href="docindex.htm">Document Index</a> <p>