Bochs调试命令

Bochs Debugger

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When you first start up bochs, you will see the command line prompt

bochs:1>

From here, you may use the following commands:

Execution Control

c                           Continue executing
stepi [count]               execute count instructions, default is 1
si    [count]               execute count instructions, default is 1
step  [count]               execute count instructions, default is 1
s     [count]               execute count instructions, default is 1
Ctrl-C                      stop execution, and return to command line prompt
Ctrl-D                      if at empty line on command line, exit
quit                        quit debugger and execution
q                           quit debugger and execution

BreakPoints

NOTE: The format of 'seg', 'off', and 'addr' in these descriptions,
are as follows.  I don't have any way to set the current radix.

hexidecimal:    0xcdef0123
decimal:        123456789
octal:          01234567

vbreak seg:off              Set a virtual address instruction breakpoint
vb     seg:off

lbreak addr                 Set a linear address instruction breakpoint
lb     addr

pbreak [*] addr             Set a physical address instruction breakpoint
pb     [*] addr             (the '*' is optional for GDB compatibility)
break  [*] addr
b      [*] addr

info break                  Display state of all current breakpoints
delete n                    Delete a breakpoint
del    n
d      n

Manipulating Memory

x  /nuf addr      Examine memory at linear address addr
xp /nuf addr      Examine memory at physical address addr
n              Count of how many units to display
u              Unit size; one of
b Individual bytes
h Halfwords (2 bytes)
w Words (4 bytes)
g Giant words (8 bytes)
NOTE: these are *not* typical Intel nomenclature sizes,
but they are consistent with GDB convention.
f              Printing format.  one of
x Print in hexadecimal
d Print in decimal
u Print in unsigned decimal
o Print in octal
t Print in binary

n, f, and u are optional parameters.  u and f default to the last values
you used, or to w(words) and x(hex) if none have been supplied.
n currently defaults to 1.  If none of these optional parameters are
used, no slash should be typed.  addr is also optional.  If you don't
specify it, it will be the value the next address (as if you had
specified n+1 in the last x command).

setpmem addr datasize val    Set physical memory location of size
datasize to value val.

crc  addr1  addr2            Show CRC for physical memory range addr1..addr2
info dirty                   Show physical pages dirtied (written to) since last display
Values displayed are the top 20 bits only (page addresses)

Info

info program      Execution status of the program
info registers    List of CPU integer registers and their contents
info break        Information about current breakpoint status
where		    Print the current call stack

Manipulating CPU Registers

set $reg = val    Change a CPU register to value val.  Registers may be one of:
eax, ecx, edx, ebx, esp, ebp, esi, edi.
Currently, you may not change:
eflags, cs, ss, ds, es, fs, gs.

Examples: set $eax = 0x01234567
set $edx = 25

info registers    See Info section
dump_cpu          Dump complete CPU state
set_cpu           Set  complete CPU state

Format of "dump_cpu" and "set_cpu":
"eax:0x%x\n"
"ebx:0x%x\n"
"ecx:0x%x\n"
"edx:0x%x\n"
"ebp:0x%x\n"
"esi:0x%x\n"
"edi:0x%x\n"
"esp:0x%x\n"
"eflags:0x%x\n"
"eip:0x%x\n"
"cs:s=0x%x, dl=0x%x, dh=0x%x, valid=%u\n"
"ss:s=0x%x, dl=0x%x, dh=0x%x, valid=%u\n"
"ds:s=0x%x, dl=0x%x, dh=0x%x, valid=%u\n"
"es:s=0x%x, dl=0x%x, dh=0x%x, valid=%u\n"
"fs:s=0x%x, dl=0x%x, dh=0x%x, valid=%u\n"
"gs:s=0x%x, dl=0x%x, dh=0x%x, valid=%u\n"
"ldtr:s=0x%x, dl=0x%x, dh=0x%x, valid=%u\n"
"tr:s=0x%x, dl=0x%x, dh=0x%x, valid=%u\n"
"gdtr:base=0x%x, limit=0x%x\n"
"idtr:base=0x%x, limit=0x%x\n"
"dr0:0x%x\n"
"dr1:0x%x\n"
"dr2:0x%x\n"
"dr3:0x%x\n"
"dr4:0x%x\n"
"dr5:0x%x\n"
"dr6:0x%x\n"
"dr7:0x%x\n"
"tr3:0x%x\n"
"tr4:0x%x\n"
"tr5:0x%x\n"
"tr6:0x%x\n"
"tr7:0x%x\n"
"cr0:0x%x\n"
"cr1:0x%x\n"
"cr2:0x%x\n"
"cr3:0x%x\n"
"cr4:0x%x\n"
"inhibit_int:%u\n"
"done\n"

Notes:
- s is the selector
- dl is the shadow descriptor low  dword (4 byte quantitiy)
- dh is the shadow descriptor high dword (4 byte quantitiy)
- valid denotes if the segment register holds a validated shadow descriptor
- inhibit_int is set if the previous instruction was one which delays the
acceptance of interrupts by one instruction (STI, MOV SS)
- any errors encountered by the set_cpu command, are reported by
"Error: ...".  They may be reported after any of the input lines,
or after the "done" line, during limit checks.
- A successful set_cpu command ends with the separate line:
"OK".

Disassembly commands

disassemble start end       Disassemble instructions in given linear address
range, inclusive of start, exclusive of end.
Use "set $disassemble_size =" to tell
debugger desired segment size.  Use a value for
end of less than start (or zero) if you only
want the first instruction disassembled.
set $disassemble_size = n   Tell debugger what segment size to use when
the "disassemble" command is used.  Use values
of 16 or 32 for n.  Default is 32.

set $auto_disassemble = n   Cause debugger to disassemble current instruction
every time execution stops if n=1.  Default is 0.
Segment size of current CPU context is used for
disassembly, so variable "$disassemble_size" is
ignored.

New Commands

trace-on

Disassemble every executed instruction. Note that instructions thatcause exceptions are not really executed, and therefore not traced.

trace-off

Disable tracing.

ptime

Print the current time (number of ticks since start of simulation(modulo 2^32)).

sb delta

Insert a time break point delta instructions into the future.

sba time

Insert a time break point at time.

record filename

Record console input to file filename. The file consists ofzero or more lines of the form "%s %d %x", where the first word is theevent type, the second is a time stamp and the third is event specificdata.

playback filename

Playback console input from file filename. Additional input canbe given directly in the console window. Events in the file will beplayed back at times relative to the time when the playback commandwas executed.

print-stack [num words]

Print the num words top 16-bit words on the stack. Numwords defaults to 16. Only works reliably in protected mode whenthe base address of the stack segment is zero.

watch stop

Stop the simulation (and return to prompt) when a watch point isencountered.

watch continue

Do not stop the simulation when watch points are encountered. They willstill be logged.

watch

Print current watch point status.

unwatch

Remove all watch points.

watch read address

Insert a read watch point at physical address address.

watch write address

Insert a write watch point at physical address address.

unwatch read address

Remove read watch point from physical address address.

unwatch write address

Remove write watch point from physical address address.

modebp [string]

Insert documentation here.

load-symbols [global] filename [offset]

Load symbols from file filename. If the global keyword isadded, then the the symbols will be visible in all contexts for whichsymbols have not been loaded.Offset (default is 0) is added toevery symbol entry. The symbols are loaded in the current
(executing)context.
The symbol file consists of zero or more lines of the format "%x%s".

show [string]

Insert documentation here.
 

 

 

Resource file extensions

time0: time

Specifies the start (boot) time of the virtual machine. Use atime value as returned by the time(2) system call.Timeequal to 1 is a special case which starts the virtual machine at thecurrent time of the simulator host.

cdromd: dev=device, status=(inserted|ejected)

LoseNT needs a CD in order to boot properly. Our simulated CD-ROM unitcommunicates directly with the CD-ROM driver in Linux.Deviceis a device special file to which the CD-ROM driver is connected(typically /dev/hdc).Device is ignored if status=ejected.