diff options
Diffstat (limited to 'c/src/lib/libbsp/i386/shared/comm/i386-stub.c')
| -rw-r--r-- | c/src/lib/libbsp/i386/shared/comm/i386-stub.c | 937 |
1 files changed, 937 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/i386/shared/comm/i386-stub.c b/c/src/lib/libbsp/i386/shared/comm/i386-stub.c new file mode 100644 index 0000000000..d4fd60ad9b --- /dev/null +++ b/c/src/lib/libbsp/i386/shared/comm/i386-stub.c @@ -0,0 +1,937 @@ +/* + * This is the gdb i386 remote debug stub from gdb 4.XX. + * + * $Id$ + */ + +/**************************************************************************** + + 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. + * Modified for RTEMS by Aleksey Romanov, Quality Quorum, Inc. + * + * 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 + */ +extern int putDebugChar (int ch); /* write a single character */ +extern int getDebugChar (void); /* read and return a single char */ + +/* assign an exception handler */ +extern void exceptionHandler (int, void (*handler) (void)); + +/************************************************************************/ +/* 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 bytes of registers. */ +#define NUMREGBYTES 64 +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[NUMREGBYTES / 4]; + +#define STACKSIZE 10000 +int remcomStack[STACKSIZE / sizeof (int)]; +static int *stackPtr = &remcomStack[STACKSIZE / sizeof (int) - 1]; + +/*************************** ASSEMBLY CODE MACROS *************************/ +/* */ + +extern void + return_to_prog (void); + +/* 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 (void) +{ + return_to_prog (); +} + +int +hex (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 $<data>#<checksum> */ +void +getpacket (char *buffer) +{ + unsigned char checksum; + unsigned char xmitcsum; + int i; + int count; + char ch; + + do + { + /* wait around for the start character, ignore all other characters */ + while ((ch = (getDebugChar () & 0x7f)) != '$'); + 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 (char *buffer) +{ + unsigned char checksum; + int count; + char ch; + + /* $<packet info>#<checksum>. */ + do + { + putDebugChar ('$'); + checksum = 0; + count = 0; + + while ((ch = buffer[count])) + { + if (!putDebugChar (ch)) + return; + 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) (void) = NULL; + +/* Indicate to caller of mem2hex or hex2mem that there has been an + error. */ +static volatile int mem_err = 0; + +void +set_mem_err (void) +{ + 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 (char *addr) +{ + return *addr; +} + +void +set_char (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 (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 (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 (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; + + /* 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; + + _returnFromException (); /* this is a jump */ + + break; + + /* kill the program */ + case 'k': /* do nothing */ + 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 (void) +{ + extern void remcomHandler (); + + 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); + + /* 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 (void) +{ + if (initialized) + { + BREAKPOINT (); + } + waitabit (); +} + +int waitlimit = 1000000; + +void +waitabit (void) +{ + int i; + for (i = 0; i < waitlimit; i++); +} + + + + + |