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Diffstat (limited to 'gdb/i386-stub.c')
| -rw-r--r-- | gdb/i386-stub.c | 927 |
1 files changed, 927 insertions, 0 deletions
diff --git a/gdb/i386-stub.c b/gdb/i386-stub.c new file mode 100644 index 0000000..768f00c --- /dev/null +++ b/gdb/i386-stub.c @@ -0,0 +1,927 @@ +/**************************************************************************** + + 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 $ + * + * Modified for 386 by Jim Kingdon, Cygnus Support. + * + * 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 external function exceptionHandler() is + * used to attach a specific handler to a specific 386 vector number. + * It should use the same privilege level it runs at. It should + * install it as an interrupt gate so that interrupts are masked + * while the handler runs. + * Also, need to assign exceptionHook and oldExceptionHook. + * + * 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> + +/************************************************************************ + * + * 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 */ + +/************************************************************************/ +/* 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 */ + +void waitabit(); + +static const char hexchars[]="0123456789abcdef"; + +/* Number of registers. */ +#define NUMREGS 16 + +/* Number of bytes of registers. */ +#define NUMREGBYTES (NUMREGS * 4) + +enum regnames {EAX, ECX, EDX, EBX, ESP, EBP, ESI, EDI, + PC /* also known as eip */, + PS /* also known as eflags */, + CS, SS, DS, ES, FS, GS}; + +/* + * these should not be static cuz they can be used outside this module + */ +int registers[NUMREGS]; + +#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; + +/*************************** ASSEMBLY CODE MACROS *************************/ +/* */ + +extern void +return_to_prog (); + +/* Restore the program's registers (including the stack pointer, which + means we get the right stack and don't have to worry about popping our + return address and any stack frames and so on) and return. */ +asm(".text"); +asm(".globl _return_to_prog"); +asm("_return_to_prog:"); +asm(" movw _registers+44, %ss"); +asm(" movl _registers+16, %esp"); +asm(" movl _registers+4, %ecx"); +asm(" movl _registers+8, %edx"); +asm(" movl _registers+12, %ebx"); +asm(" movl _registers+20, %ebp"); +asm(" movl _registers+24, %esi"); +asm(" movl _registers+28, %edi"); +asm(" movw _registers+48, %ds"); +asm(" movw _registers+52, %es"); +asm(" movw _registers+56, %fs"); +asm(" movw _registers+60, %gs"); +asm(" movl _registers+36, %eax"); +asm(" pushl %eax"); /* saved eflags */ +asm(" movl _registers+40, %eax"); +asm(" pushl %eax"); /* saved cs */ +asm(" movl _registers+32, %eax"); +asm(" pushl %eax"); /* saved eip */ +asm(" movl _registers, %eax"); +/* use iret to restore pc and flags together so + that trace flag works right. */ +asm(" iret"); + +#define BREAKPOINT() asm(" int $3"); + +/* Put the error code here just in case the user cares. */ +int gdb_i386errcode; +/* Likewise, the vector number here (since GDB only gets the signal + number through the usual means, and that's not very specific). */ +int gdb_i386vector = -1; + +/* GDB stores segment registers in 32-bit words (that's just the way + m-i386v.h is written). So zero the appropriate areas in registers. */ +#define SAVE_REGISTERS1() \ + asm ("movl %eax, _registers"); \ + asm ("movl %ecx, _registers+4"); \ + asm ("movl %edx, _registers+8"); \ + asm ("movl %ebx, _registers+12"); \ + asm ("movl %ebp, _registers+20"); \ + asm ("movl %esi, _registers+24"); \ + asm ("movl %edi, _registers+28"); \ + asm ("movw $0, %ax"); \ + asm ("movw %ds, _registers+48"); \ + asm ("movw %ax, _registers+50"); \ + asm ("movw %es, _registers+52"); \ + asm ("movw %ax, _registers+54"); \ + asm ("movw %fs, _registers+56"); \ + asm ("movw %ax, _registers+58"); \ + asm ("movw %gs, _registers+60"); \ + asm ("movw %ax, _registers+62"); +#define SAVE_ERRCODE() \ + asm ("popl %ebx"); \ + asm ("movl %ebx, _gdb_i386errcode"); +#define SAVE_REGISTERS2() \ + asm ("popl %ebx"); /* old eip */ \ + asm ("movl %ebx, _registers+32"); \ + asm ("popl %ebx"); /* old cs */ \ + asm ("movl %ebx, _registers+40"); \ + asm ("movw %ax, _registers+42"); \ + asm ("popl %ebx"); /* old eflags */ \ + asm ("movl %ebx, _registers+36"); \ + /* Now that we've done the pops, we can save the stack pointer."); */ \ + asm ("movw %ss, _registers+44"); \ + asm ("movw %ax, _registers+46"); \ + asm ("movl %esp, _registers+16"); + +/* See if mem_fault_routine is set, if so just IRET to that address. */ +#define CHECK_FAULT() \ + asm ("cmpl $0, _mem_fault_routine"); \ + asm ("jne mem_fault"); + +asm (".text"); +asm ("mem_fault:"); +/* OK to clobber temp registers; we're just going to end up in set_mem_err. */ +/* Pop error code from the stack and save it. */ +asm (" popl %eax"); +asm (" movl %eax, _gdb_i386errcode"); + +asm (" popl %eax"); /* eip */ +/* We don't want to return there, we want to return to the function + pointed to by mem_fault_routine instead. */ +asm (" movl _mem_fault_routine, %eax"); +asm (" popl %ecx"); /* cs (low 16 bits; junk in hi 16 bits). */ +asm (" popl %edx"); /* eflags */ + +/* Remove this stack frame; when we do the iret, we will be going to + the start of a function, so we want the stack to look just like it + would after a "call" instruction. */ +asm (" leave"); + +/* Push the stuff that iret wants. */ +asm (" pushl %edx"); /* eflags */ +asm (" pushl %ecx"); /* cs */ +asm (" pushl %eax"); /* eip */ + +/* Zero mem_fault_routine. */ +asm (" movl $0, %eax"); +asm (" movl %eax, _mem_fault_routine"); + +asm ("iret"); + +#define CALL_HOOK() asm("call _remcomHandler"); + +/* This function is called when a i386 exception occurs. It saves + * all the cpu regs in the _registers array, munges the stack a bit, + * and invokes an exception handler (remcom_handler). + * + * stack on entry: stack on exit: + * old eflags vector number + * old cs (zero-filled to 32 bits) + * old eip + * + */ +extern void _catchException3(); +asm(".text"); +asm(".globl __catchException3"); +asm("__catchException3:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $3"); +CALL_HOOK(); + +/* Same thing for exception 1. */ +extern void _catchException1(); +asm(".text"); +asm(".globl __catchException1"); +asm("__catchException1:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $1"); +CALL_HOOK(); + +/* Same thing for exception 0. */ +extern void _catchException0(); +asm(".text"); +asm(".globl __catchException0"); +asm("__catchException0:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $0"); +CALL_HOOK(); + +/* Same thing for exception 4. */ +extern void _catchException4(); +asm(".text"); +asm(".globl __catchException4"); +asm("__catchException4:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $4"); +CALL_HOOK(); + +/* Same thing for exception 5. */ +extern void _catchException5(); +asm(".text"); +asm(".globl __catchException5"); +asm("__catchException5:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $5"); +CALL_HOOK(); + +/* Same thing for exception 6. */ +extern void _catchException6(); +asm(".text"); +asm(".globl __catchException6"); +asm("__catchException6:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $6"); +CALL_HOOK(); + +/* Same thing for exception 7. */ +extern void _catchException7(); +asm(".text"); +asm(".globl __catchException7"); +asm("__catchException7:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $7"); +CALL_HOOK(); + +/* Same thing for exception 8. */ +extern void _catchException8(); +asm(".text"); +asm(".globl __catchException8"); +asm("__catchException8:"); +SAVE_REGISTERS1(); +SAVE_ERRCODE(); +SAVE_REGISTERS2(); +asm ("pushl $8"); +CALL_HOOK(); + +/* Same thing for exception 9. */ +extern void _catchException9(); +asm(".text"); +asm(".globl __catchException9"); +asm("__catchException9:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $9"); +CALL_HOOK(); + +/* Same thing for exception 10. */ +extern void _catchException10(); +asm(".text"); +asm(".globl __catchException10"); +asm("__catchException10:"); +SAVE_REGISTERS1(); +SAVE_ERRCODE(); +SAVE_REGISTERS2(); +asm ("pushl $10"); +CALL_HOOK(); + +/* Same thing for exception 12. */ +extern void _catchException12(); +asm(".text"); +asm(".globl __catchException12"); +asm("__catchException12:"); +SAVE_REGISTERS1(); +SAVE_ERRCODE(); +SAVE_REGISTERS2(); +asm ("pushl $12"); +CALL_HOOK(); + +/* Same thing for exception 16. */ +extern void _catchException16(); +asm(".text"); +asm(".globl __catchException16"); +asm("__catchException16:"); +SAVE_REGISTERS1(); +SAVE_REGISTERS2(); +asm ("pushl $16"); +CALL_HOOK(); + +/* For 13, 11, and 14 we have to deal with the CHECK_FAULT stuff. */ + +/* Same thing for exception 13. */ +extern void _catchException13 (); +asm (".text"); +asm (".globl __catchException13"); +asm ("__catchException13:"); +CHECK_FAULT(); +SAVE_REGISTERS1(); +SAVE_ERRCODE(); +SAVE_REGISTERS2(); +asm ("pushl $13"); +CALL_HOOK(); + +/* Same thing for exception 11. */ +extern void _catchException11 (); +asm (".text"); +asm (".globl __catchException11"); +asm ("__catchException11:"); +CHECK_FAULT(); +SAVE_REGISTERS1(); +SAVE_ERRCODE(); +SAVE_REGISTERS2(); +asm ("pushl $11"); +CALL_HOOK(); + +/* Same thing for exception 14. */ +extern void _catchException14 (); +asm (".text"); +asm (".globl __catchException14"); +asm ("__catchException14:"); +CHECK_FAULT(); +SAVE_REGISTERS1(); +SAVE_ERRCODE(); +SAVE_REGISTERS2(); +asm ("pushl $14"); +CALL_HOOK(); + +/* + * remcomHandler is a front end for handle_exception. It moves the + * stack pointer into an area reserved for debugger use. + */ +asm("_remcomHandler:"); +asm(" popl %eax"); /* pop off return address */ +asm(" popl %eax"); /* get the exception number */ +asm(" movl _stackPtr, %esp"); /* move to remcom stack area */ +asm(" pushl %eax"); /* push exception onto stack */ +asm(" call _handle_exception"); /* this never returns */ + +void _returnFromException() +{ + return_to_prog (); +} + +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); +} + + +/* scan for the sequence $<data>#<checksum> */ +void getpacket(buffer) +char * buffer; +{ + unsigned char checksum; + unsigned char xmitcsum; + int i; + int count; + char ch; + + do { + /* wait around for the start character, ignore all other characters */ + while ((ch = (getDebugChar() & 0x7f)) != '$'); + checksum = 0; + xmitcsum = -1; + + count = 0; + + /* now, read until a # or end of buffer is found */ + while (count < BUFMAX) { + ch = getDebugChar() & 0x7f; + if (ch == '#') break; + checksum = checksum + ch; + buffer[count] = ch; + count = count + 1; + } + buffer[count] = 0; + + if (ch == '#') { + xmitcsum = hex(getDebugChar() & 0x7f) << 4; + xmitcsum += hex(getDebugChar() & 0x7f); + if ((remote_debug ) && (checksum != xmitcsum)) { + fprintf (stderr ,"bad checksum. My count = 0x%x, sent=0x%x. buf=%s\n", + checksum,xmitcsum,buffer); + } + + if (checksum != xmitcsum) 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] ); + /* remove sequence chars from buffer */ + count = strlen(buffer); + for (i=3; i <= count; i++) buffer[i-3] = buffer[i]; + } + } + } + } while (checksum != xmitcsum); + +} + +/* 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() & 0x7f) != '+'); + +} + +char remcomInBuffer[BUFMAX]; +char remcomOutBuffer[BUFMAX]; +static short error; + + +void debug_error(format, parm) +char * format; +char * parm; +{ + if (remote_debug) fprintf (stderr,format,parm); +} + +/* Address of a routine to RTE to if we get a memory fault. */ +static void (*volatile mem_fault_routine)() = NULL; + +/* Indicate to caller of mem2hex or hex2mem that there has been an + error. */ +static volatile int mem_err = 0; + +void +set_mem_err () +{ + mem_err = 1; +} + +/* These are separate functions so that they are so short and sweet + that the compiler won't save any registers (if there is a fault + to mem_fault, they won't get restored, so there better not be any + saved). */ +int +get_char (addr) + char *addr; +{ + return *addr; +} + +void +set_char (addr, val) + char *addr; + int val; +{ + *addr = val; +} + +/* convert the memory pointed to by mem into hex, placing result in buf */ +/* return a pointer to the last char put in buf (null) */ +/* If MAY_FAULT is non-zero, then we should set mem_err in response to + a fault; if zero treat a fault like any other fault in the stub. */ +char* mem2hex(mem, buf, count, may_fault) +char* mem; +char* buf; +int count; +int may_fault; +{ + int i; + unsigned char ch; + + if (may_fault) + mem_fault_routine = set_mem_err; + for (i=0;i<count;i++) { + ch = get_char (mem++); + if (may_fault && mem_err) + return (buf); + *buf++ = hexchars[ch >> 4]; + *buf++ = hexchars[ch % 16]; + } + *buf = 0; + if (may_fault) + mem_fault_routine = NULL; + 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, may_fault) +char* buf; +char* mem; +int count; +int may_fault; +{ + int i; + unsigned char ch; + + if (may_fault) + mem_fault_routine = set_mem_err; + for (i=0;i<count;i++) { + ch = hex(*buf++) << 4; + ch = ch + hex(*buf++); + set_char (mem++, ch); + if (may_fault && mem_err) + return (mem); + } + if (may_fault) + mem_fault_routine = NULL; + return(mem); +} + +/* this function takes the 386 exception vector and attempts to + translate this number into a unix compatible signal value */ +int computeSignal( exceptionVector ) +int exceptionVector; +{ + int sigval; + switch (exceptionVector) { + case 0 : sigval = 8; break; /* divide by zero */ + case 1 : sigval = 5; break; /* debug exception */ + case 3 : sigval = 5; break; /* breakpoint */ + case 4 : sigval = 16; break; /* into instruction (overflow) */ + case 5 : sigval = 16; break; /* bound instruction */ + case 6 : sigval = 4; break; /* Invalid opcode */ + case 7 : sigval = 8; break; /* coprocessor not available */ + case 8 : sigval = 7; break; /* double fault */ + case 9 : sigval = 11; break; /* coprocessor segment overrun */ + case 10 : sigval = 11; break; /* Invalid TSS */ + case 11 : sigval = 11; break; /* Segment not present */ + case 12 : sigval = 11; break; /* stack exception */ + case 13 : sigval = 11; break; /* general protection */ + case 14 : sigval = 11; break; /* page fault */ + case 16 : sigval = 7; break; /* coprocessor error */ + 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; + int addr, length; + char * ptr; + int newPC; + + gdb_i386vector = exceptionVector; + + 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); + + while (1==1) { + error = 0; + remcomOutBuffer[0] = 0; + getpacket(remcomInBuffer); + switch (remcomInBuffer[0]) { + 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, 0); + break; + case 'G' : /* set the value of the CPU registers - return OK */ + hex2mem(&remcomInBuffer[1], (char*) registers, NUMREGBYTES, 0); + strcpy(remcomOutBuffer,"OK"); + break; + case 'P' : /* set the value of a single CPU register - return OK */ + { + int regno; + + ptr = &remcomInBuffer[1]; + if (hexToInt (&ptr, ®no) && *ptr++ == '=') + if (regno >= 0 && regno < NUMREGS) + { + hex2mem (ptr, (char *)®isters[regno], 4, 0); + strcpy(remcomOutBuffer,"OK"); + break; + } + + strcpy (remcomOutBuffer, "E01"); + break; + } + + /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ + case 'm' : + /* TRY TO READ %x,%x. IF SUCCEED, SET PTR = 0 */ + ptr = &remcomInBuffer[1]; + if (hexToInt(&ptr,&addr)) + if (*(ptr++) == ',') + if (hexToInt(&ptr,&length)) + { + ptr = 0; + mem_err = 0; + mem2hex((char*) addr, remcomOutBuffer, length, 1); + if (mem_err) { + strcpy (remcomOutBuffer, "E03"); + debug_error ("memory fault"); + } + } + + if (ptr) + { + strcpy(remcomOutBuffer,"E01"); + debug_error("malformed read memory command: %s",remcomInBuffer); + } + break; + + /* MAA..AA,LLLL: Write LLLL bytes at address AA.AA return OK */ + case 'M' : + /* TRY TO READ '%x,%x:'. IF SUCCEED, SET PTR = 0 */ + ptr = &remcomInBuffer[1]; + if (hexToInt(&ptr,&addr)) + if (*(ptr++) == ',') + if (hexToInt(&ptr,&length)) + if (*(ptr++) == ':') + { + mem_err = 0; + hex2mem(ptr, (char*) addr, length, 1); + + if (mem_err) { + strcpy (remcomOutBuffer, "E03"); + debug_error ("memory fault"); + } else { + strcpy(remcomOutBuffer,"OK"); + } + + ptr = 0; + } + if (ptr) + { + strcpy(remcomOutBuffer,"E02"); + debug_error("malformed write memory command: %s",remcomInBuffer); + } + break; + + /* cAA..AA Continue at address AA..AA(optional) */ + /* sAA..AA Step one instruction from AA..AA(optional) */ + case 'c' : + case 's' : + /* try to read optional parameter, pc unchanged if no parm */ + ptr = &remcomInBuffer[1]; + if (hexToInt(&ptr,&addr)) + registers[ PC ] = addr; + + newPC = registers[ PC]; + + /* clear the trace bit */ + registers[ PS ] &= 0xfffffeff; + + /* set the trace bit if we're stepping */ + if (remcomInBuffer[0] == 's') registers[ PS ] |= 0x100; + + /* + * 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 0 + /* Don't really think we need this, except maybe for protection + exceptions. */ + /* + * invoke the previous handler. + */ + if (oldExceptionHook) + (*oldExceptionHook) (frame->exceptionVector); + newPC = registers[ PC ]; /* pc may have changed */ +#endif /* 0 */ + + _returnFromException(); /* this is a jump */ + + break; + + /* kill the program */ + case 'k' : /* do nothing */ +#if 0 + /* Huh? This doesn't look like "nothing". + m68k-stub.c and sparc-stub.c don't have it. */ + BREAKPOINT(); +#endif + break; + } /* switch */ + + /* reply to the request */ + putpacket(remcomOutBuffer); + } +} + +/* this function is used to set up exception handlers for tracing and + breakpoints */ +void set_debug_traps() +{ +extern void remcomHandler(); +int exception; + + stackPtr = &remcomStack[STACKSIZE/sizeof(int) - 1]; + + exceptionHandler (0, _catchException0); + exceptionHandler (1, _catchException1); + exceptionHandler (3, _catchException3); + exceptionHandler (4, _catchException4); + exceptionHandler (5, _catchException5); + exceptionHandler (6, _catchException6); + exceptionHandler (7, _catchException7); + exceptionHandler (8, _catchException8); + exceptionHandler (9, _catchException9); + exceptionHandler (10, _catchException10); + exceptionHandler (11, _catchException11); + exceptionHandler (12, _catchException12); + exceptionHandler (13, _catchException13); + exceptionHandler (14, _catchException14); + exceptionHandler (16, _catchException16); + + if (exceptionHook != remcomHandler) + { + oldExceptionHook = exceptionHook; + exceptionHook = remcomHandler; + } + + /* In case GDB is started before us, ack any packets (presumably + "$?#xx") sitting there. */ + putDebugChar ('+'); + + 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) +#if 0 + handle_exception(3); +#else + BREAKPOINT(); +#endif + waitabit(); +} + +int waitlimit = 1000000; + +void +waitabit() +{ + int i; + for (i = 0; i < waitlimit; i++) ; +} |