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<HTML><HEAD> <META NAME="copyright" CONTENT="Copyright 2001 by MandrakeSoft S.A."> <META NAME="Author" CONTENT="Kevin Lawton"> <META HTTP-EQUIV="Content-Type" CONTENT="text/html;CHARSET=iso-8859-1"> <TITLE>Cosimulating: Using Bochs debugger to drive 2 simulators</TITLE></HEAD><BODY TEXT="#000000" BGCOLOR="#ececec" LINK="#3333cc" VLINK="#666666"><CENTER><H1><I>Welcome to the Bochs x86 PC Emulation Software Home Page!</I></H1></CENTER><CENTER><H1>Cosimulating: using Bochs debugger to drive 2 simulators</H1></CENTER><HR SIZE=5 NOSHADE><H2>What is Cosimulation?</H2><IMG SRC="undercon.gif" ALT="Under Construction">I'll add a discussion of cosimulation here soon.<HR SIZE=5 NOSHADE><H2>Cosimulation Programmatic Interface</H2><IMG SRC="undercon.gif" ALT="Under Construction">This documentation is not yet complete, and this interface issubject to change.<HR><HR><H3>Callback Structure:</H3><P>Upon startup, the cosimulation controller (debugger) will initialize eachsimulator (or emulator) by calling an init routine. There are 2macro's in config.h (generated from config.h.in), which determinethe names of the initialization routines, one for each simulator.These macro's are BX_SIM1_INIT and BX_SIM2_INIT. The first onelikely can be kept as is. You will need to edit the secondone, to be a routine in the second simulator which will receivea few parameters, and fill in a callback structure. This is theonly routine in each simulator environment which is needed directly,as the callback routines which are filled in, are used subsequently.It should be of the type:<PRE> void some_name_here(bx_dbg_callback_t *, int argc, char *argv[]);</PRE>The <I>argc</I> and <I>argv</I> parameters are as you might expect.They consist of any simulator specific command line options passed tothe bochs executable at program invocation time. Since there can bemore than one simulator, command line options are delimited by<I>-sim1</I> and <I>-sim2</I> as in:<PRE> Usage: bochs [-rc path] [-sim1 ... ] [-sim2 ...]</PRE>The first parameter is the address of a callback structure, whose type<I>bx_dbg_callback_t</I> is defined in debug/debug.h. Most fieldsare function pointers, though some are not. Below, is a descriptionof each field in the callback structure.<P><PRE> typedef struct { bx_bool (*setphymem)(Bit32u addr, unsigned len, Bit8u *buf); bx_bool (*getphymem)(Bit32u addr, unsigned len, Bit8u *buf); void (*xlate_linear2phy)(Bit32u linear, Bit32u *phy, bx_bool *valid); bx_bool (*set_reg)(unsigned reg, Bit32u val); Bit32u (*get_reg)(unsigned reg); bx_bool (*set_cpu)(bx_dbg_cpu_t *cpu); bx_bool (*get_cpu)(bx_dbg_cpu_t *cpu); unsigned dirty_page_tbl_size; unsigned char *dirty_page_tbl; void (*atexit)(void); unsigned (*query_pending)(void); void (*execute)(void); void (*take_irq)(void); void (*take_dma)(void); void (*reset_cpu)(unsigned source); void (*init_mem)(int size_in_bytes); void (*load_ROM)(const char *path, Bit32u romaddress); void (*set_A20)(unsigned val); void (*set_NMI)(unsigned val); void (*set_RESET)(unsigned val); void (*set_INTR)(unsigned val); void (*force_interrupt)(unsigned vector); #if BX_INSTRUMENTATION void (*instr_start)(void); void (*instr_stop)(void); void (*instr_reset)(void); void (*instr_print)(void); #endif #if BX_USE_LOADER void (*loader)(char *path); #endif } bx_dbg_callback_t;</PRE><P><B>bx_bool (*setphymem)(Bit32u addr, unsigned len, Bit8u *buf);</B><P>Set (write to) physical memory of simulator at address <I>addr</I> from the<I>len</I> bytes in <I>buf</I>. The bytes in <I>buf</I> should be copied to the simulator'sphysical memory byte-at-a-time with no concern for endian-ness. Return 1if the write is OK, 0 if an error occurs.<P><B>bx_bool (*getphymem)(Bit32u addr, unsigned len, Bit8u *buf);</B><P>Get (read from) physical memory of simulator at address <I>addr</I> to the<I>len</I> bytes in <I>buf</I>. The bytes in <I>buf</I> should be copied from the simulator'sphysical memory byte-at-a-time with no concern for endian-ness. Return 1if the read is OK, 0 if an error occurs.<P><B>void (*xlate_linear2phy)(Bit32u linear, Bit32u *phy, bx_bool *valid);</B><P>Translate a linear to a physical address, without generating an exceptionor updating the paging tables. The debugger passes the simulator the<I>linear</I> address. The simulator is expected to set <I>phy</I> tothe corresponding physical address if available, and update <I>valid</I>,which should be set to 1 if the physical address was available, and 0if not. It is possible, the address is not in the paging tables, andthus not available.<P><B>bx_bool (*set_reg)(unsigned reg, Bit32u val);</B><P>Set a specific CPU register as determined by <I>reg</I> in thesimulator to <I>val</I>. The value of <I>reg</I> will be one of thedefines, such as BX_DBG_REG_EAX defined in <I>debug/debug.h</I>. Thesegment registers can only be set by this method in real mode. Thisfunction should return a 1 if the operation is successful, and 0 if not.<P><B>Bit32u (*get_reg)(unsigned reg);</B><P>Return the value of a specific CPU register in the simulator asdetermined by <I>reg</I>, whose value is of the same rangeas those passed into <I>set_reg()</I><P><B>bx_bool (*set_cpu)(bx_dbg_cpu_t *cpu);</B><P>Set all the registers in the CPU simulator to those in the structure<I>cpu</I>. The <I>bx_dbg_cpu_t</I> structure is defined in debug/debug.h.<P><B>bx_bool (*get_cpu)(bx_dbg_cpu_t *cpu);</B><P>Get values for all the registers in the CPU simulator, and place them inthe structure <I>cpu</I>. The <I>bx_dbg_cpu_t</I> structure is defined in debug/debug.h.<P><B>unsigned dirty_page_tbl_size;</B><BR><B>unsigned char *dirty_page_tbl;</B><P>To keep track of what areas of memory have been written to, and allowthe debugger to efficiently compare regions of memory in each simulator,each simulator should provide a dirty page table. It is expected thateach byte in the array represents one 4K page of physical memory. A valueof 1 represents that the page has been written to, since the last time itwas cleared by the debugger, and a value of 0 represents that no writehas occurred within that physical page.<P>You should fill in the field <I>dirty_page_tbl</I> with a pointerto an array of bytes. And <I>dirty_page_tbl_size</I> should be setto the size of the array in bytes. If possible, make the array bigenough to span the largest amount of physical memory you might request.I chose to not make this size dynamic with the user's requested memory size,to eliminate an extra access via a pointer.<P><B>void (*atexit)(void);</B><P>Called when the debugger needs to terminate execution. This functionshould close files and do all necessary shutdown of the simulator.<B>NOTE:</B> Do not call exit() directly fromthe simulator, but instead call <I>bx_dbg_exit()</I>. As there may be multiplesimulators, <I>bx_dbg_exit()</I> will handle invoking the <I>atexit</I> callback ineach simulator first, and then it will call exit().<P><B>void (*execute)(void);</B><P>The debugger calls <I>execute()</I> in either slave or master simulator,commanding either to execute instructions until a guard is reached, in whichcase control should be returned back to the debugger.<P><B>void (*reset_cpu)(unsigned source);</B><P>This function is called once by the debugger to initialize the simulator'sCPU upon program startup. <I>Source</I> will be eitherBX_RESET_HARDWARE or BX_RESET_SOFTWARE.<P><B>void (*init_mem)(int size_in_bytes);</B><P>This function is called once by the debugger to initialize the simulator'smemory upon program startup. <I>Size_in_bytes</I> denotesthe size of physical memory the user has requested, so that both simulatorscan use the same physical memory size. This would be an appropriatetime to allocate memory for the simulator.<P><B>void (*load_ROM)(const char *path, Bit32u romaddress);</B><P>Commands the simulator to load a ROM image stored in the filename<I>path</I> into physical memory at address <I>romaddress</I>.<P><B>void (*set_A20)(unsigned val);</B><P>This function is called by the cosim controller to command either masteror slave simulator to change it's A20 setting. If the value of <I>val</I> passedis 1, then the A20 address line is passed through and used. This will givenormal addressing of the entire 32bit address space. If the value is 0,then A20 is masked out, and addressing at the 1Meg boundary will wrap, modeling8086 addressing.<P>The cosim controller also commands the <I>bx_pc_system</I> class tomaintain the same A20 state as passed in this function, so you may alternativelyuse values directly from that class, rather than keep your own A20 state.If so, set the value of <I>set_A20</I> to NULL, and use the followingmembers from <I>bx_pc_system</I>. In this case, <I>set_A20</I> won't becalled.<UL><LI><B>bx_pc_system.enable_a20:</B> Same value as passed to <I>set_A20</I>.<LI><B>bx_pc_system.a20_mask:</B> Logical AND this with a physical address to obtain theaddress after application of the A20 gate.</UL><P><B>void (*set_NMI)(unsigned val);</B><P>Not supported yet. Will tell the simulator that the value ofthe NMI pin, is currently <I>val</I>. Use an empty stub functionfor this for now.<P><B>void (*set_RESET)(unsigned val);</B><P>Not supported yet. Will tell the simulator that the value ofthe RESET pin, is currently <I>val</I>. Use an empty stub functionfor this for now.<P><B>void (*set_INTR)(unsigned val);</B><P>The INTR pin is driven by the device models. When the INTR pin israised due to an interrupt request by the PIC, or lowered after theinterrupt is acknowledged, this function is called to notify thesimulator of the new status. Only the master simulator will receivenotification, as INTR is always 0 for the slave simulator. Interruptsare forced in the slave simulator, synchronizing it to the executionpath of the master, using <I>force_interrupt()</I> described below.A value in <I>val</I> of 0 indicates no interrupt is requested. A valueof 1 indicates an interrupt request.<P><B>void (*force_interrupt)(unsigned vector);</B><P>In order for the debugger to force the slave simulator to take aninterrupt at the same point as the master simulator, the interrupt vectoris recorded when taken by the master simulator. The debugger commandsthe slave to the same point, and calls this routine, forcing the slaveto take the given interrupt, <I>vector</I>.<P><B>void (*instr_start)(void);</B> (Only defined if macro BX_INSTRUMENTATION is 1)<P>Called when the user types in "<I>instrument start</I>" at the debug prompt.The instrumentation package can use this function to do whatever isnecessary to initialize the instrumentation package and/or commandit to begin collecting data.<P><B>void (*instr_stop)(void);</B> (Only defined if macro BX_INSTRUMENTATION is 1)<P>Called when the user types in "<I>instrument stop</I>" at the debug prompt.The instrumentation package can use this function to do whatever isnecessary to temporarily or permanently stop the instrumentation packagefrom collecting data.<P><B>void (*instr_reset)(void);</B> (Only defined if macro BX_INSTRUMENTATION is 1)<P>Called when the user types in "<I>instrument reset</I>" at the debug prompt.The instrumentation package can use this function to command the instrumentationpackage to reset it's data collection mechanisms.<P><B>void (*instr_print)(void);</B> (Only defined if macro BX_INSTRUMENTATION is 1)<P>Called when the user types in "<I>instrument print</I>" at the debug prompt.The instrumentation package can use this function to output it's collecteddata.<P><B>void (*loader)(char *path);</B> (Only defined if macro BX_USE_LOADER is 1)<P>Called when the user types in "<I>loader pathname</I>" at the debug prompt.The idea is to allow a loader routine to read in a program which is specificto the OS you are running within the emulator, from a file on your nativeworkstation, load it properly into simulator memory and run it on thesimulator. This loader must be specific to the OS you are running within thesimulator, and I do not provide one with bochs.<P><B>void (*take_irq)(void);</B><BR><B>void (*take_dma)(void);</B><BR><B>unsigned (*query_pending)(void);</B><P>These are vestiges of a past interface. They correspond to the"take irq", "take dma", and "query pending" commands, which youshouldn't use. They will be removed. Set these fields to NULL,or to empty stub functions.<HR><HR><H3>Debugger (Cosimulation Controller) Functions:</H3><P><B>void bx_dbg_exit(int code)</B><P>When there is a situation in the simulator, where you need to terminatedue to an unrecoverable error (panic), call <I>bx_dbg_exit()</I>. Amongother things, this function will call the <I>at_exit</I> callback functionin each simulator, and ultimately call the system exit() function.<P><B>Bit8u bx_dbg_IAC(void)</B><P>The simulator's CPU code should call this function when it is acknowledging aninterrupt from the PIC via the INTR line. The interrupt vector number from the PICis returned.<P><B>Bit32u bx_dbg_inp(Bit16u addr, unsigned len)</B><P>To read data from an IO device, the simulator should call this function.Pass in the IO address <I>addr</I>, and the size of the IO operation <I>len</I>.<P><B>void bx_dbg_outp(Bit16u addr, Bit32u value, unsigned len)</B><P>To write data to an IO device, the simulator should call this function.Pass in the IO address <I>addr</I>, and the size of the IO operation <I>len</I>.<P><B>Bit8u bx_dbg_ucmem_read(Bit32u addr)</B><BR><B>void bx_dbg_ucmem_write(Bit32u addr, Bit8u value)</B><P>For memory read/write accesses which fall in the range of 0xA0000 to 0xBFFFF,the accesses should not be to directed to the simulator's memory, sincethese are UnCacheable MEMory addresses. The VGA adapter maps it's memory to thisrange. Instead, call these functions to perform reads/writes to memoryaccesses in this range. For <I>bx_dbg_ucmem_read()</I>, pass the physical address<I>addr</I>, and the value of the read is returned. For <I>bx_dbg_ucmem_write()</I>,pass the physical address <I>addr</I> and value <I>value</I> of the write.⌨️ 快捷键说明
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