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<HTML><HEAD> <META NAME="resource-type" CONTENT="document"> <META NAME="distribution" CONTENT="GLOBAL"> <META NAME="description" CONTENT="Bochs command line debugger"> <META NAME="copyright" CONTENT="Copyright 2001 by MandrakeSoft S.A."> <META NAME="keywords" CONTENT="pc emulation, x86 emulation, emulator"> <META NAME="Author" CONTENT="Kevin Lawton"> <META HTTP-EQUIV="Content-Type" CONTENT="text/html;CHARSET=iso-8859-1"> <TITLE>Bochs Debugger</TITLE></HEAD><BODY TEXT="#000000" BGCOLOR="#ececec" LINK="#3333cc" VLINK="#666666"><CENTER><H1>Debugger</H1></CENTER><P>Note, if you are looking for a graphical front-end for thebochs debugger, you may want to check out<a href="http://www.qzx.com/bfe/">BFE</a>. This is apackage written by a bochs user which can interface withthe text based bochs debugger. No linking is necessary.It's not part of bochs, but you may find it useful.<P>You can now conditionally compile in a GDB like command line debugger, thatallows you to set breakpoints, step through instructions, and otheruseful functions. If there isn't a command for something you believeis generally useful for the debugger, let me know and I'll implementit if possible.<P>To use the debugger, you must configure bochs with the'--enable-debugger' and '--enable-disasm' flags. For example:<PRE> ./configure --enable-debugger --enable-disasm</PRE>NOTE: You must use flex version 2.5.4 or greater. I have heard thatversion 2.5.2 will not work.<P>When you first start up bochs, you will see the command line prompt<PRE> bochs:1></PRE>From here, you may use the following commands:<H3>Execution Control</H3><PRE> 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</PRE><H3>BreakPoints</H3><PRE> 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</PRE><H3>Manipulating Memory</H3><PRE> 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)</PRE><H3>Info</H3><PRE> info program Execution status of the program info registers List of CPU integer registers and their contents info break Information about current breakpoint status</PRE><H3>Manipulating CPU Registers</H3><PRE> 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".</PRE><H3>Disassembly commands</H3><PRE> 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 0, 16 or 32 for n. Value of 0 means "use segment size specified by current CS segment". Default is 0. 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.</PRE><H3>Instrumentation</H3><PRE>To use instrumentation features in bochs, you must compile in support for it.You should build a custom instrumentation library in a separate directory inthe "instrument/" directory. To tell configure which instrumentation libraryyou want to use, use the "--enable-instrumentation" option.The default library consists of a set of stubs, and the following areequivalent: ./configure [...] --enable-instrumentation ./configure [...] --enable-instrumentation="instrument/stubs"You could make a separate directory with your custom library,for example "instrument/myinstrument", copy the contents ofthe "instrument/stubs" directory to it, then customize it. Use: ./configure [...] --enable-instrumentation="instrument/myinstrument"</PRE><H3>Instrumentation commands</H3><PRE> instrument start calls bx_instr_start() instrument stop calls bx_instr_stop() instrument reset calls bx_instr_reset() instrument print calls bx_instr_print()</PRE><HR><h2>New Commands</h2><h3>trace-on</h3>Disassemble every executed instruction. Note that instructions thatcause exceptions are not really executed, and therefore not traced.<h3>trace-off</h3>Disable tracing.<h3>ptime</h3>Print the current time (number of ticks since start of simulation(modulo 2^32)).<h3>sb <i>delta</i></h3>Insert a time break point <i>delta</i> instructions into the future.<h3>sba <i>time</i></h3>Insert a time break point at <i>time</i>.<h3>record <i>filename</i></h3>Record console input to file <i>filename</i>. 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.<h3>playback <i>filename</i></h3>Playback console input from file <i>filename</i>. 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.<h3>print-stack [<i>num words</i>]</h3>Print the <i>num words</i> top 16-bit words on the stack. <i>Numwords</i> defaults to 16. Only works reliably in protected mode whenthe base address of the stack segment is zero.<h3>watch stop</h3>Stop the simulation (and return to prompt) when a watch point isencountered.<h3>watch continue</h3>Do not stop the simulation when watch points are encountered. They willstill be logged.<h3>watch</h3>Print current watch point status.<h3>unwatch</h3>Remove all watch points.<h3>watch read <i>address</i></h3>Insert a read watch point at physical address <i>address</i>.<h3>watch write address</h3>Insert a write watch point at physical address <i>address</i>.<h3>unwatch read <i>address</i></h3>Remove read watch point from physical address <i>address</i>.<h3>unwatch write <i>address</i></h3>Remove write watch point from physical address <i>address</i>.<h3>modebp [<i>string</i>]</h3>Toggles vm86 mode switch breakpoint.<h3>load-symbols [global] <i>filename</i> [<i>offset</i>]</h3>Load symbols from file <i>filename</i>. If the global keyword isadded, then the the symbols will be visible in all contexts for whichsymbols have not been loaded. <i>Offset</i> (default is 0) is added toevery symbol entry. The symbols are loaded in the current (executing)context.<p>The symbol file consists of zero or more lines of the format <tt>"%x%s"</tt>.<h3>show [<i>string</i>]</h3><PRE> Toggles show symbolic info (calls to begin with). show - shows current show mode show "mode" - show, when processor switch mode show "int" - show, when interrupt is happens show "call" - show, when call is happens show "ret" - show, when iret is happens show "off" - toggles off symbolic info show "dbg-all" - turn on all show flags show "none" - turn off all show flags</PRE><p> <p> <p> <h2>Resource file extensions</h2><h3>time0: <i>time</i></h3>Specifies the start (boot) time of the virtual machine. Use a<i>time</i> value as returned by the time(2) system call. <i>Time</i>equal to 1 is a special case which starts the virtual machine at thecurrent time of the simulator host.<h3>cdromd: dev=<i>device</i>, status=(inserted|ejected)</h3>LoseNT needs a CD in order to boot properly. Our simulated CD-ROM unitcommunicates directly with the CD-ROM driver in Linux. <i>Device</i>is a device special file to which the CD-ROM driver is connected(typically /dev/hdc). <i>Device</i> is ignored if status=ejected.<HR><P>Related Links:<UL><LI><A HREF="cosimulation.html">Cosimulation</A><LI><A HREF="instrumentation.html">Instrumentation</A></UL></BODY></HTML>⌨️ 快捷键说明
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