c_t.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 t Command</title>
<h1>t/to</h1>

<!--INDEX "t command" "to command" "single step" "trace command"  -->

The t command performs a trace (single step) operation.<p>

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

The format for this command is:<p>

<pre>
t [-vbci]
</pre>

or:<p>

<pre>
to [-vbci]
</pre>

where:<p>

<dl><dd>
<table><tr><td>
-v	</td><td>lists each step (verbose).
</td></tr><tr><td>
-b	</td><td>captures only branches.
</td></tr><tr><td>
-c	</td><td>captures only calls (jal instruction).
</td></tr><tr><td>
-i	</td><td>stops on invalid program counter.
</td></tr><tr><td>
cnt	</td><td>traces cnt instructions.
</td></tr></table><p>
</dl>

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

The t command executes the instruction addressed by the current value
of the EPC register. The to command is similar to the t command, except
that the to command treats an entire procedure as a single step. For
example, if the current instruction at EPC is a jump and link
instruction, jal, the next stop is at EPC+8.<p>

A branch instruction and the instruction in its delay slot are executed
as a single step. This also means that two-instruction loops are treated
as a single step. This command is implemented by setting a 
<a href="brkpts.htm">breakpoint</a> at the following instruction.<p>

The command or commands that are executed on completion of the single 
step is determined by the value of the environment variable brkcmd.<p>

An example illustrating the use of this command follows.<p>

<pre>
	PMON> t 
	Pmon+0x240 3c09a07f lui t1,0xa07f
</pre>

</dl><h2>Files</h2><dl><dd>
The t/to commands are located in <a href="../mon/go.c">mon/go.c</a>.

</dl><p><hr>
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