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Diffstat (limited to 'gdb/m68k-stub.c')
| -rw-r--r-- | gdb/m68k-stub.c | 1098 |
1 files changed, 0 insertions, 1098 deletions
diff --git a/gdb/m68k-stub.c b/gdb/m68k-stub.c deleted file mode 100644 index 54e06b1..0000000 --- a/gdb/m68k-stub.c +++ /dev/null @@ -1,1098 +0,0 @@ -/**************************************************************************** - - THIS SOFTWARE IS NOT COPYRIGHTED - - HP offers the following for use in the public domain. HP makes no - warranty with regard to the software or it's performance and the - user accepts the software "AS IS" with all faults. - - HP DISCLAIMS ANY WARRANTIES, EXPRESS OR IMPLIED, WITH REGARD - TO THIS SOFTWARE INCLUDING BUT NOT LIMITED TO THE WARRANTIES - OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. - -****************************************************************************/ - -/**************************************************************************** - * Header: remcom.c,v 1.34 91/03/09 12:29:49 glenne Exp $ - * - * Module name: remcom.c $ - * Revision: 1.34 $ - * Date: 91/03/09 12:29:49 $ - * Contributor: Lake Stevens Instrument Division$ - * - * Description: low level support for gdb debugger. $ - * - * Considerations: only works on target hardware $ - * - * Written by: Glenn Engel $ - * ModuleState: Experimental $ - * - * NOTES: See Below $ - * - * To enable debugger support, two things need to happen. One, a - * call to set_debug_traps() is necessary in order to allow any breakpoints - * or error conditions to be properly intercepted and reported to gdb. - * Two, a breakpoint needs to be generated to begin communication. This - * is most easily accomplished by a call to breakpoint(). Breakpoint() - * simulates a breakpoint by executing a trap #1. The breakpoint instruction - * is hardwired to trap #1 because not to do so is a compatibility problem-- - * there either should be a standard breakpoint instruction, or the protocol - * should be extended to provide some means to communicate which breakpoint - * instruction is in use (or have the stub insert the breakpoint). - * - * Some explanation is probably necessary to explain how exceptions are - * handled. When an exception is encountered the 68000 pushes the current - * program counter and status register onto the supervisor stack and then - * transfers execution to a location specified in it's vector table. - * The handlers for the exception vectors are hardwired to jmp to an address - * given by the relation: (exception - 256) * 6. These are decending - * addresses starting from -6, -12, -18, ... By allowing 6 bytes for - * each entry, a jsr, jmp, bsr, ... can be used to enter the exception - * handler. Using a jsr to handle an exception has an added benefit of - * allowing a single handler to service several exceptions and use the - * return address as the key differentiation. The vector number can be - * computed from the return address by [ exception = (addr + 1530) / 6 ]. - * The sole purpose of the routine _catchException is to compute the - * exception number and push it on the stack in place of the return address. - * The external function exceptionHandler() is - * used to attach a specific handler to a specific m68k exception. - * For 68020 machines, the ability to have a return address around just - * so the vector can be determined is not necessary because the '020 pushes an - * extra word onto the stack containing the vector offset - * - * Because gdb will sometimes write to the stack area to execute function - * calls, this program cannot rely on using the supervisor stack so it - * uses it's own stack area reserved in the int array remcomStack. - * - ************* - * - * The following gdb commands are supported: - * - * command function Return value - * - * g return the value of the CPU registers hex data or ENN - * G set the value of the CPU registers OK or ENN - * - * mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN - * MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN - * - * c Resume at current address SNN ( signal NN) - * cAA..AA Continue at address AA..AA SNN - * - * s Step one instruction SNN - * sAA..AA Step one instruction from AA..AA SNN - * - * k kill - * - * ? What was the last sigval ? SNN (signal NN) - * - * All commands and responses are sent with a packet which includes a - * checksum. A packet consists of - * - * $<packet info>#<checksum>. - * - * where - * <packet info> :: <characters representing the command or response> - * <checksum> :: < two hex digits computed as modulo 256 sum of <packetinfo>> - * - * When a packet is received, it is first acknowledged with either '+' or '-'. - * '+' indicates a successful transfer. '-' indicates a failed transfer. - * - * Example: - * - * Host: Reply: - * $m0,10#2a +$00010203040506070809101112131415#42 - * - ****************************************************************************/ - -#include <stdio.h> -#include <string.h> -#include <setjmp.h> - -/************************************************************************ - * - * external low-level support routines - */ -typedef void (*ExceptionHook)(int); /* pointer to function with int parm */ -typedef void (*Function)(); /* pointer to a function */ - -extern void putDebugChar(); /* write a single character */ -extern int getDebugChar(); /* read and return a single char */ - -extern Function exceptionHandler(); /* assign an exception handler */ -extern ExceptionHook exceptionHook; /* hook variable for errors/exceptions */ - -/************************/ -/* FORWARD DECLARATIONS */ -/************************/ -static void -initializeRemcomErrorFrame (); - -/************************************************************************/ -/* BUFMAX defines the maximum number of characters in inbound/outbound buffers*/ -/* at least NUMREGBYTES*2 are needed for register packets */ -#define BUFMAX 400 - -static char initialized; /* boolean flag. != 0 means we've been initialized */ - -int remote_debug; -/* debug > 0 prints ill-formed commands in valid packets & checksum errors */ - -static const char hexchars[]="0123456789abcdef"; - -/* there are 180 bytes of registers on a 68020 w/68881 */ -/* many of the fpa registers are 12 byte (96 bit) registers */ -#define NUMREGBYTES 180 -enum regnames {D0,D1,D2,D3,D4,D5,D6,D7, - A0,A1,A2,A3,A4,A5,A6,A7, - PS,PC, - FP0,FP1,FP2,FP3,FP4,FP5,FP6,FP7, - FPCONTROL,FPSTATUS,FPIADDR - }; - - -/* We keep a whole frame cache here. "Why?", I hear you cry, "doesn't - GDB handle that sort of thing?" Well, yes, I believe the only - reason for this cache is to save and restore floating point state - (fsave/frestore). A cleaner way to do this would be to make the - fsave data part of the registers which GDB deals with like any - other registers. This should not be a performance problem if the - ability to read individual registers is added to the protocol. */ - -typedef struct FrameStruct -{ - struct FrameStruct *previous; - int exceptionPC; /* pc value when this frame created */ - int exceptionVector; /* cpu vector causing exception */ - short frameSize; /* size of cpu frame in words */ - short sr; /* for 68000, this not always sr */ - int pc; - short format; - int fsaveHeader; - int morejunk[0]; /* exception frame, fp save... */ -} Frame; - -#define FRAMESIZE 500 -int gdbFrameStack[FRAMESIZE]; -static Frame *lastFrame; - -/* - * these should not be static cuz they can be used outside this module - */ -int registers[NUMREGBYTES/4]; -int superStack; - -#define STACKSIZE 10000 -int remcomStack[STACKSIZE/sizeof(int)]; -static int* stackPtr = &remcomStack[STACKSIZE/sizeof(int) - 1]; - -/* - * In many cases, the system will want to continue exception processing - * when a continue command is given. - * oldExceptionHook is a function to invoke in this case. - */ - -static ExceptionHook oldExceptionHook; - -#ifdef mc68020 -/* the size of the exception stack on the 68020 varies with the type of - * exception. The following table is the number of WORDS used - * for each exception format. - */ -const short exceptionSize[] = { 4,4,6,4,4,4,4,4,29,10,16,46,12,4,4,4 }; -#endif - -#ifdef mc68332 -static const short exceptionSize[] = { 4,4,6,4,4,4,4,4,4,4,4,4,16,4,4,4 }; -#endif - -/************* jump buffer used for setjmp/longjmp **************************/ -jmp_buf remcomEnv; - -/*************************** ASSEMBLY CODE MACROS *************************/ -/* */ - -#ifdef __HAVE_68881__ -/* do an fsave, then remember the address to begin a restore from */ -#define SAVE_FP_REGS() asm(" fsave a0@-"); \ - asm(" fmovemx fp0-fp7,_registers+72"); \ - asm(" fmoveml fpcr/fpsr/fpi,_registers+168"); -#define RESTORE_FP_REGS() \ -asm(" \n\ - fmoveml _registers+168,fpcr/fpsr/fpi \n\ - fmovemx _registers+72,fp0-fp7 \n\ - cmpl #-1,a0@ | skip frestore flag set ? \n\ - beq skip_frestore \n\ - frestore a0@+ \n\ -skip_frestore: \n\ -"); - -#else -#define SAVE_FP_REGS() -#define RESTORE_FP_REGS() -#endif /* __HAVE_68881__ */ - -void return_to_super(); -void return_to_user(); - -asm(" -.text -.globl _return_to_super -_return_to_super: - movel _registers+60,sp /* get new stack pointer */ - movel _lastFrame,a0 /* get last frame info */ - bra return_to_any - -.globl _return_to_user -_return_to_user: - movel _registers+60,a0 /* get usp */ - movel a0,usp /* set usp */ - movel _superStack,sp /* get original stack pointer */ - -return_to_any: - movel _lastFrame,a0 /* get last frame info */ - movel a0@+,_lastFrame /* link in previous frame */ - addql #8,a0 /* skip over pc, vector#*/ - movew a0@+,d0 /* get # of words in cpu frame */ - addw d0,a0 /* point to end of data */ - addw d0,a0 /* point to end of data */ - movel a0,a1 -# -# copy the stack frame - subql #1,d0 -copyUserLoop: - movew a1@-,sp@- - dbf d0,copyUserLoop -"); - RESTORE_FP_REGS() - asm(" moveml _registers,d0-d7/a0-a6"); - asm(" rte"); /* pop and go! */ - -#define DISABLE_INTERRUPTS() asm(" oriw #0x0700,sr"); -#define BREAKPOINT() asm(" trap #1"); - -/* this function is called immediately when a level 7 interrupt occurs */ -/* if the previous interrupt level was 7 then we're already servicing */ -/* this interrupt and an rte is in order to return to the debugger. */ -/* For the 68000, the offset for sr is 6 due to the jsr return address */ -asm(" -.text -.globl __debug_level7 -__debug_level7: - movew d0,sp@-"); -#if defined (mc68020) || defined (mc68332) -asm(" movew sp@(2),d0"); -#else -asm(" movew sp@(6),d0"); -#endif -asm(" andiw #0x700,d0 - cmpiw #0x700,d0 - beq _already7 - movew sp@+,d0 - bra __catchException -_already7: - movew sp@+,d0"); -#if !defined (mc68020) && !defined (mc68332) -asm(" lea sp@(4),sp"); /* pull off 68000 return address */ -#endif -asm(" rte"); - -extern void _catchException (); - -#if defined (mc68020) || defined (mc68332) -/* This function is called when a 68020 exception occurs. It saves - * all the cpu and fpcp regs in the _registers array, creates a frame on a - * linked list of frames which has the cpu and fpcp stack frames needed - * to properly restore the context of these processors, and invokes - * an exception handler (remcom_handler). - * - * stack on entry: stack on exit: - * N bytes of junk exception # MSWord - * Exception Format Word exception # MSWord - * Program counter LSWord - * Program counter MSWord - * Status Register - * - * - */ -asm(" -.text -.globl __catchException -__catchException:"); -DISABLE_INTERRUPTS(); -asm(" - moveml d0-d7/a0-a6,_registers /* save registers */ - movel _lastFrame,a0 /* last frame pointer */ -"); -SAVE_FP_REGS(); -asm(" - lea _registers,a5 /* get address of registers */ - movew sp@,d1 /* get status register */ - movew d1,a5@(66) /* save sr */ - movel sp@(2),a4 /* save pc in a4 for later use */ - movel a4,a5@(68) /* save pc in _regisers[] */ - -# -# figure out how many bytes in the stack frame - movew sp@(6),d0 /* get '020 exception format */ - movew d0,d2 /* make a copy of format word */ - andiw #0xf000,d0 /* mask off format type */ - rolw #5,d0 /* rotate into the low byte *2 */ - lea _exceptionSize,a1 - addw d0,a1 /* index into the table */ - movew a1@,d0 /* get number of words in frame */ - movew d0,d3 /* save it */ - subw d0,a0 /* adjust save pointer */ - subw d0,a0 /* adjust save pointer(bytes) */ - movel a0,a1 /* copy save pointer */ - subql #1,d0 /* predecrement loop counter */ -# -# copy the frame -saveFrameLoop: - movew sp@+,a1@+ - dbf d0,saveFrameLoop -# -# now that the stack has been clenaed, -# save the a7 in use at time of exception - movel sp,_superStack /* save supervisor sp */ - andiw #0x2000,d1 /* were we in supervisor mode ? */ - beq userMode - movel a7,a5@(60) /* save a7 */ - bra a7saveDone -userMode: - movel usp,a1 - movel a1,a5@(60) /* save user stack pointer */ -a7saveDone: - -# -# save size of frame - movew d3,a0@- - -# -# compute exception number - andl #0xfff,d2 /* mask off vector offset */ - lsrw #2,d2 /* divide by 4 to get vect num */ - movel d2,a0@- /* save it */ -# -# save pc causing exception - movel a4,a0@- -# -# save old frame link and set the new value - movel _lastFrame,a1 /* last frame pointer */ - movel a1,a0@- /* save pointer to prev frame */ - movel a0,_lastFrame - - movel d2,sp@- /* push exception num */ - movel _exceptionHook,a0 /* get address of handler */ - jbsr a0@ /* and call it */ - clrl sp@ /* replace exception num parm with frame ptr */ - jbsr __returnFromException /* jbsr, but never returns */ -"); -#else /* mc68000 */ -/* This function is called when an exception occurs. It translates the - * return address found on the stack into an exception vector # which - * is then handled by either handle_exception or a system handler. - * _catchException provides a front end for both. - * - * stack on entry: stack on exit: - * Program counter MSWord exception # MSWord - * Program counter LSWord exception # MSWord - * Status Register - * Return Address MSWord - * Return Address LSWord - */ -asm(" -.text -.globl __catchException -__catchException:"); -DISABLE_INTERRUPTS(); -asm(" - moveml d0-d7/a0-a6,_registers /* save registers */ - movel _lastFrame,a0 /* last frame pointer */ -"); -SAVE_FP_REGS(); -asm(" - lea _registers,a5 /* get address of registers */ - movel sp@+,d2 /* pop return address */ - addl #1530,d2 /* convert return addr to */ - divs #6,d2 /* exception number */ - extl d2 - - moveql #3,d3 /* assume a three word frame */ - - cmpiw #3,d2 /* bus error or address error ? */ - bgt normal /* if >3 then normal error */ - movel sp@+,a0@- /* copy error info to frame buff*/ - movel sp@+,a0@- /* these are never used */ - moveql #7,d3 /* this is a 7 word frame */ - -normal: - movew sp@+,d1 /* pop status register */ - movel sp@+,a4 /* pop program counter */ - movew d1,a5@(66) /* save sr */ - movel a4,a5@(68) /* save pc in _regisers[] */ - movel a4,a0@- /* copy pc to frame buffer */ - movew d1,a0@- /* copy sr to frame buffer */ - - movel sp,_superStack /* save supervisor sp */ - - andiw #0x2000,d1 /* were we in supervisor mode ? */ - beq userMode - movel a7,a5@(60) /* save a7 */ - bra saveDone -userMode: - movel usp,a1 /* save user stack pointer */ - movel a1,a5@(60) /* save user stack pointer */ -saveDone: - - movew d3,a0@- /* push frame size in words */ - movel d2,a0@- /* push vector number */ - movel a4,a0@- /* push exception pc */ - -# -# save old frame link and set the new value - movel _lastFrame,a1 /* last frame pointer */ - movel a1,a0@- /* save pointer to prev frame */ - movel a0,_lastFrame - - movel d2,sp@- /* push exception num */ - movel _exceptionHook,a0 /* get address of handler */ - jbsr a0@ /* and call it */ - clrl sp@ /* replace exception num parm with frame ptr */ - jbsr __returnFromException /* jbsr, but never returns */ -"); -#endif - - -/* - * remcomHandler is a front end for handle_exception. It moves the - * stack pointer into an area reserved for debugger use in case the - * breakpoint happened in supervisor mode. - */ -asm("_remcomHandler:"); -asm(" addl #4,sp"); /* pop off return address */ -asm(" movel sp@+,d0"); /* get the exception number */ -asm(" movel _stackPtr,sp"); /* move to remcom stack area */ -asm(" movel d0,sp@-"); /* push exception onto stack */ -asm(" jbsr _handle_exception"); /* this never returns */ -asm(" rts"); /* return */ - -void -_returnFromException (Frame * frame) -{ - /* if no passed in frame, use the last one */ - if (!frame) - { - frame = lastFrame; - frame->frameSize = 4; - frame->format = 0; - frame->fsaveHeader = -1; /* restore regs, but we dont have fsave info */ - } - -#if !defined (mc68020) && !defined (mc68332) - /* a 68000 cannot use the internal info pushed onto a bus error - * or address error frame when doing an RTE so don't put this info - * onto the stack or the stack will creep every time this happens. - */ - frame->frameSize = 3; -#endif - - /* throw away any frames in the list after this frame */ - lastFrame = frame; - - frame->sr = registers[(int) PS]; - frame->pc = registers[(int) PC]; - - if (registers[(int) PS] & 0x2000) - { - /* return to supervisor mode... */ - return_to_super (); - } - else - { /* return to user mode */ - return_to_user (); - } -} - -int -hex (ch) - char ch; -{ - if ((ch >= 'a') && (ch <= 'f')) - return (ch - 'a' + 10); - if ((ch >= '0') && (ch <= '9')) - return (ch - '0'); - if ((ch >= 'A') && (ch <= 'F')) - return (ch - 'A' + 10); - return (-1); -} - -static char remcomInBuffer[BUFMAX]; -static char remcomOutBuffer[BUFMAX]; - -/* scan for the sequence $<data>#<checksum> */ - -unsigned char * -getpacket (void) -{ - unsigned char *buffer = &remcomInBuffer[0]; - unsigned char checksum; - unsigned char xmitcsum; - int count; - char ch; - - while (1) - { - /* wait around for the start character, ignore all other characters */ - while ((ch = getDebugChar ()) != '$') - ; - - retry: - checksum = 0; - xmitcsum = -1; - count = 0; - - /* now, read until a # or end of buffer is found */ - while (count < BUFMAX) - { - ch = getDebugChar (); - if (ch == '$') - goto retry; - if (ch == '#') - break; - checksum = checksum + ch; - buffer[count] = ch; - count = count + 1; - } - buffer[count] = 0; - - if (ch == '#') - { - ch = getDebugChar (); - xmitcsum = hex (ch) << 4; - ch = getDebugChar (); - xmitcsum += hex (ch); - - if (checksum != xmitcsum) - { - if (remote_debug) - { - fprintf (stderr, - "bad checksum. My count = 0x%x, sent=0x%x. buf=%s\n", - checksum, xmitcsum, buffer); - } - putDebugChar ('-'); /* failed checksum */ - } - else - { - putDebugChar ('+'); /* successful transfer */ - - /* if a sequence char is present, reply the sequence ID */ - if (buffer[2] == ':') - { - putDebugChar (buffer[0]); - putDebugChar (buffer[1]); - - return &buffer[3]; - } - - return &buffer[0]; - } - } - } -} - -/* send the packet in buffer. */ - -void -putpacket (buffer) - char *buffer; -{ - unsigned char checksum; - int count; - char ch; - - /* $<packet info>#<checksum>. */ - do - { - putDebugChar ('$'); - checksum = 0; - count = 0; - - while (ch = buffer[count]) - { - putDebugChar (ch); - checksum += ch; - count += 1; - } - - putDebugChar ('#'); - putDebugChar (hexchars[checksum >> 4]); - putDebugChar (hexchars[checksum % 16]); - - } - while (getDebugChar () != '+'); - -} - -void -debug_error (format, parm) - char *format; - char *parm; -{ - if (remote_debug) - fprintf (stderr, format, parm); -} - -/* convert the memory pointed to by mem into hex, placing result in buf */ -/* return a pointer to the last char put in buf (null) */ -char * -mem2hex (mem, buf, count) - char *mem; - char *buf; - int count; -{ - int i; - unsigned char ch; - for (i = 0; i < count; i++) - { - ch = *mem++; - *buf++ = hexchars[ch >> 4]; - *buf++ = hexchars[ch % 16]; - } - *buf = 0; - return (buf); -} - -/* convert the hex array pointed to by buf into binary to be placed in mem */ -/* return a pointer to the character AFTER the last byte written */ -char * -hex2mem (buf, mem, count) - char *buf; - char *mem; - int count; -{ - int i; - unsigned char ch; - for (i = 0; i < count; i++) - { - ch = hex (*buf++) << 4; - ch = ch + hex (*buf++); - *mem++ = ch; - } - return (mem); -} - -/* a bus error has occurred, perform a longjmp - to return execution and allow handling of the error */ - -void -handle_buserror () -{ - longjmp (remcomEnv, 1); -} - -/* this function takes the 68000 exception number and attempts to - translate this number into a unix compatible signal value */ -int -computeSignal (exceptionVector) - int exceptionVector; -{ - int sigval; - switch (exceptionVector) - { - case 2: - sigval = 10; - break; /* bus error */ - case 3: - sigval = 10; - break; /* address error */ - case 4: - sigval = 4; - break; /* illegal instruction */ - case 5: - sigval = 8; - break; /* zero divide */ - case 6: - sigval = 8; - break; /* chk instruction */ - case 7: - sigval = 8; - break; /* trapv instruction */ - case 8: - sigval = 11; - break; /* privilege violation */ - case 9: - sigval = 5; - break; /* trace trap */ - case 10: - sigval = 4; - break; /* line 1010 emulator */ - case 11: - sigval = 4; - break; /* line 1111 emulator */ - - /* Coprocessor protocol violation. Using a standard MMU or FPU - this cannot be triggered by software. Call it a SIGBUS. */ - case 13: - sigval = 10; - break; - - case 31: - sigval = 2; - break; /* interrupt */ - case 33: - sigval = 5; - break; /* breakpoint */ - - /* This is a trap #8 instruction. Apparently it is someone's software - convention for some sort of SIGFPE condition. Whose? How many - people are being screwed by having this code the way it is? - Is there a clean solution? */ - case 40: - sigval = 8; - break; /* floating point err */ - - case 48: - sigval = 8; - break; /* floating point err */ - case 49: - sigval = 8; - break; /* floating point err */ - case 50: - sigval = 8; - break; /* zero divide */ - case 51: - sigval = 8; - break; /* underflow */ - case 52: - sigval = 8; - break; /* operand error */ - case 53: - sigval = 8; - break; /* overflow */ - case 54: - sigval = 8; - break; /* NAN */ - default: - sigval = 7; /* "software generated" */ - } - return (sigval); -} - -/**********************************************/ -/* WHILE WE FIND NICE HEX CHARS, BUILD AN INT */ -/* RETURN NUMBER OF CHARS PROCESSED */ -/**********************************************/ -int -hexToInt (char **ptr, int *intValue) -{ - int numChars = 0; - int hexValue; - - *intValue = 0; - - while (**ptr) - { - hexValue = hex (**ptr); - if (hexValue >= 0) - { - *intValue = (*intValue << 4) | hexValue; - numChars++; - } - else - break; - - (*ptr)++; - } - - return (numChars); -} - -/* - * This function does all command procesing for interfacing to gdb. - */ -void -handle_exception (int exceptionVector) -{ - int sigval, stepping; - int addr, length; - char *ptr; - int newPC; - Frame *frame; - - if (remote_debug) - printf ("vector=%d, sr=0x%x, pc=0x%x\n", - exceptionVector, registers[PS], registers[PC]); - - /* reply to host that an exception has occurred */ - sigval = computeSignal (exceptionVector); - remcomOutBuffer[0] = 'S'; - remcomOutBuffer[1] = hexchars[sigval >> 4]; - remcomOutBuffer[2] = hexchars[sigval % 16]; - remcomOutBuffer[3] = 0; - - putpacket (remcomOutBuffer); - - stepping = 0; - - while (1 == 1) - { - remcomOutBuffer[0] = 0; - ptr = getpacket (); - switch (*ptr++) - { - case '?': - remcomOutBuffer[0] = 'S'; - remcomOutBuffer[1] = hexchars[sigval >> 4]; - remcomOutBuffer[2] = hexchars[sigval % 16]; - remcomOutBuffer[3] = 0; - break; - case 'd': - remote_debug = !(remote_debug); /* toggle debug flag */ - break; - case 'g': /* return the value of the CPU registers */ - mem2hex ((char *) registers, remcomOutBuffer, NUMREGBYTES); - break; - case 'G': /* set the value of the CPU registers - return OK */ - hex2mem (ptr, (char *) registers, NUMREGBYTES); - strcpy (remcomOutBuffer, "OK"); - break; - - /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ - case 'm': - if (setjmp (remcomEnv) == 0) - { - exceptionHandler (2, handle_buserror); - - /* TRY TO READ %x,%x. IF SUCCEED, SET PTR = 0 */ - if (hexToInt (&ptr, &addr)) - if (*(ptr++) == ',') - if (hexToInt (&ptr, &length)) - { - ptr = 0; - mem2hex ((char *) addr, remcomOutBuffer, length); - } - - if (ptr) - { - strcpy (remcomOutBuffer, "E01"); - } - } - else - { - exceptionHandler (2, _catchException); - strcpy (remcomOutBuffer, "E03"); - debug_error ("bus error"); - } - - /* restore handler for bus error */ - exceptionHandler (2, _catchException); - break; - - /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */ - case 'M': - if (setjmp (remcomEnv) == 0) - { - exceptionHandler (2, handle_buserror); - - /* TRY TO READ '%x,%x:'. IF SUCCEED, SET PTR = 0 */ - if (hexToInt (&ptr, &addr)) - if (*(ptr++) == ',') - if (hexToInt (&ptr, &length)) - if (*(ptr++) == ':') - { - hex2mem (ptr, (char *) addr, length); - ptr = 0; - strcpy (remcomOutBuffer, "OK"); - } - if (ptr) - { - strcpy (remcomOutBuffer, "E02"); - } - } - else - { - exceptionHandler (2, _catchException); - strcpy (remcomOutBuffer, "E03"); - debug_error ("bus error"); - } - - /* restore handler for bus error */ - exceptionHandler (2, _catchException); - break; - - /* cAA..AA Continue at address AA..AA(optional) */ - /* sAA..AA Step one instruction from AA..AA(optional) */ - case 's': - stepping = 1; - case 'c': - /* try to read optional parameter, pc unchanged if no parm */ - if (hexToInt (&ptr, &addr)) - registers[PC] = addr; - - newPC = registers[PC]; - - /* clear the trace bit */ - registers[PS] &= 0x7fff; - - /* set the trace bit if we're stepping */ - if (stepping) - registers[PS] |= 0x8000; - - /* - * look for newPC in the linked list of exception frames. - * if it is found, use the old frame it. otherwise, - * fake up a dummy frame in returnFromException(). - */ - if (remote_debug) - printf ("new pc = 0x%x\n", newPC); - frame = lastFrame; - while (frame) - { - if (remote_debug) - printf ("frame at 0x%x has pc=0x%x, except#=%d\n", - frame, frame->exceptionPC, frame->exceptionVector); - if (frame->exceptionPC == newPC) - break; /* bingo! a match */ - /* - * for a breakpoint instruction, the saved pc may - * be off by two due to re-executing the instruction - * replaced by the trap instruction. Check for this. - */ - if ((frame->exceptionVector == 33) && - (frame->exceptionPC == (newPC + 2))) - break; - if (frame == frame->previous) - { - frame = 0; /* no match found */ - break; - } - frame = frame->previous; - } - - /* - * If we found a match for the PC AND we are not returning - * as a result of a breakpoint (33), - * trace exception (9), nmi (31), jmp to - * the old exception handler as if this code never ran. - */ - if (frame) - { - if ((frame->exceptionVector != 9) && - (frame->exceptionVector != 31) && - (frame->exceptionVector != 33)) - { - /* - * invoke the previous handler. - */ - if (oldExceptionHook) - (*oldExceptionHook) (frame->exceptionVector); - newPC = registers[PC]; /* pc may have changed */ - if (newPC != frame->exceptionPC) - { - if (remote_debug) - printf ("frame at 0x%x has pc=0x%x, except#=%d\n", - frame, frame->exceptionPC, - frame->exceptionVector); - /* re-use the last frame, we're skipping it (longjump?) */ - frame = (Frame *) 0; - _returnFromException (frame); /* this is a jump */ - } - } - } - - /* if we couldn't find a frame, create one */ - if (frame == 0) - { - frame = lastFrame - 1; - - /* by using a bunch of print commands with breakpoints, - it's possible for the frame stack to creep down. If it creeps - too far, give up and reset it to the top. Normal use should - not see this happen. - */ - if ((unsigned int) (frame - 2) < (unsigned int) &gdbFrameStack) - { - initializeRemcomErrorFrame (); - frame = lastFrame; - } - frame->previous = lastFrame; - lastFrame = frame; - frame = 0; /* null so _return... will properly initialize it */ - } - - _returnFromException (frame); /* this is a jump */ - - break; - - /* kill the program */ - case 'k': /* do nothing */ - break; - } /* switch */ - - /* reply to the request */ - putpacket (remcomOutBuffer); - } -} - - -void -initializeRemcomErrorFrame (void) -{ - lastFrame = ((Frame *) & gdbFrameStack[FRAMESIZE - 1]) - 1; - lastFrame->previous = lastFrame; -} - -/* this function is used to set up exception handlers for tracing and - breakpoints */ -void -set_debug_traps () -{ - extern void _debug_level7 (); - extern void remcomHandler (); - int exception; - - initializeRemcomErrorFrame (); - stackPtr = &remcomStack[STACKSIZE / sizeof (int) - 1]; - - for (exception = 2; exception <= 23; exception++) - exceptionHandler (exception, _catchException); - - /* level 7 interrupt */ - exceptionHandler (31, _debug_level7); - - /* breakpoint exception (trap #1) */ - exceptionHandler (33, _catchException); - - /* This is a trap #8 instruction. Apparently it is someone's software - convention for some sort of SIGFPE condition. Whose? How many - people are being screwed by having this code the way it is? - Is there a clean solution? */ - exceptionHandler (40, _catchException); - - /* 48 to 54 are floating point coprocessor errors */ - for (exception = 48; exception <= 54; exception++) - exceptionHandler (exception, _catchException); - - if (oldExceptionHook != remcomHandler) - { - oldExceptionHook = exceptionHook; - exceptionHook = remcomHandler; - } - - initialized = 1; - -} - -/* This function will generate a breakpoint exception. It is used at the - beginning of a program to sync up with a debugger and can be used - otherwise as a quick means to stop program execution and "break" into - the debugger. */ - -void -breakpoint () -{ - if (initialized) - BREAKPOINT (); -} |