c_bt

MIPS处理器的bootloader,龙芯就是用的修改过的PMON2

bt The bt command displays a function call backtrace.

Format The format for this command is:

bt [-v] [ cnt]

where:
-v	specifies that each function抯 stackframe base address and size should be displayed.
cnt	specifies the number of lines to be displayed.

When invoking this command with no options, the backtrace displays the
names and up to four arguments for each level of stackframe.


Functional
Description

The bt command displays a list of function calls, starting with the function in
which the EPC register currently lies, and finishing when a return address
becomes 憫invalid拻. An address is deemed invalid if it does not lie within one
of the ranges specified by the validpcenvironment variable.

Each line of output gives the current position in a function, and up to four of
its arguments. The arguments can only be retrieved if they are saved within
the function prologue, and this is unlikely to be the case for assembler functions
and optimised C code. If you want to be able to see the arguments to C
functions, then compile your program with optimisation disabled.

If the -v option is given, then the command additionally displays the stackframe
base address and size for each function. It will also indicate the
amount of dynamic stack space allocated using C抯 alloca function, or
equivalent.

The output of this command is passed to the more command, letting the user
view one screenful of output at a time. Optionally, the user can specify cnt,
which limits the number of lines to that number. An example illustrating the
use of the bt command follows.

PMON> c write+10
write+0x0010 3c09a07f lui t1,0xa07f
PMON> bt
write+0x0010 (0x00000001,0xa0030300,0x0000001c)
flsbuf+0x0234 (0xa0030300,0xa0029030)
printf+0x045c (0xa0025490,0xa0020000,0x000000001,0x00000010)
main+0x0138 (0x00000001,0xa07ffffe0)
_start+0x0040 ()

See also the more command