1025 lines
34 KiB
C
1025 lines
34 KiB
C
/****************************************************************************
|
||
|
||
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.
|
||
|
||
****************************************************************************/
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||
|
||
/****************************************************************************
|
||
* Header: remcom.c,v 1.34 91/03/09 12:29:49 glenne Exp $
|
||
*
|
||
* Module name: remcom.c $
|
||
* Revision: 1.34 $
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||
* Date: 91/03/09 12:29:49 $
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||
* 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
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||
* calls, this program cannot rely on using the supervisor stack so it
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||
* uses it's own stack area reserved in the int array remcomStack.
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||
*
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||
*************
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||
*
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||
* 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
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||
*
|
||
* mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN
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* MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN
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||
*
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||
* c Resume at current address SNN ( signal NN)
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||
* cAA..AA Continue at address AA..AA SNN
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||
*
|
||
* s Step one instruction SNN
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||
* sAA..AA Step one instruction from AA..AA SNN
|
||
*
|
||
* k kill
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||
*
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||
* ? What was the last sigval ? SNN (signal NN)
|
||
*
|
||
* All commands and responses are sent with a packet which includes a
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||
* 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
|
||
*
|
||
****************************************************************************/
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||
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#include <stdio.h>
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#include <string.h>
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#include <setjmp.h>
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/************************************************************************
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*
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* external low-level support routines
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||
*/
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||
typedef void (*ExceptionHook)(int); /* pointer to function with int parm */
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||
typedef void (*Function)(); /* pointer to a function */
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||
|
||
extern void putDebugChar(); /* write a single character */
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||
extern int getDebugChar(); /* read and return a single char */
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||
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||
extern Function exceptionHandler(); /* assign an exception handler */
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||
extern ExceptionHook exceptionHook; /* hook variable for errors/exceptions */
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||
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||
/************************/
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||
/* FORWARD DECLARATIONS */
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||
/************************/
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||
static void
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||
initializeRemcomErrorFrame ();
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||
|
||
/************************************************************************/
|
||
/* BUFMAX defines the maximum number of characters in inbound/outbound buffers*/
|
||
/* at least NUMREGBYTES*2 are needed for register packets */
|
||
#define BUFMAX 400
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||
|
||
static char initialized; /* boolean flag. != 0 means we've been initialized */
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||
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||
int remote_debug;
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||
/* debug > 0 prints ill-formed commands in valid packets & checksum errors */
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||
|
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static const char hexchars[]="0123456789abcdef";
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||
|
||
/* there are 180 bytes of registers on a 68020 w/68881 */
|
||
/* many of the fpa registers are 12 byte (96 bit) registers */
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#define NUMREGBYTES 180
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enum regnames {D0,D1,D2,D3,D4,D5,D6,D7,
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A0,A1,A2,A3,A4,A5,A6,A7,
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PS,PC,
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||
FP0,FP1,FP2,FP3,FP4,FP5,FP6,FP7,
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FPCONTROL,FPSTATUS,FPIADDR
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||
};
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||
|
||
|
||
/* We keep a whole frame cache here. "Why?", I hear you cry, "doesn't
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GDB handle that sort of thing?" Well, yes, I believe the only
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||
reason for this cache is to save and restore floating point state
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(fsave/frestore). A cleaner way to do this would be to make the
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fsave data part of the registers which GDB deals with like any
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other registers. This should not be a performance problem if the
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ability to read individual registers is added to the protocol. */
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||
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||
typedef struct FrameStruct
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||
{
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||
struct FrameStruct *previous;
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||
int exceptionPC; /* pc value when this frame created */
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||
int exceptionVector; /* cpu vector causing exception */
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||
short frameSize; /* size of cpu frame in words */
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||
short sr; /* for 68000, this not always sr */
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||
int pc;
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||
short format;
|
||
int fsaveHeader;
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||
int morejunk[0]; /* exception frame, fp save... */
|
||
} Frame;
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||
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||
#define FRAMESIZE 500
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int gdbFrameStack[FRAMESIZE];
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static Frame *lastFrame;
|
||
|
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/*
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||
* these should not be static cuz they can be used outside this module
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*/
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||
int registers[NUMREGBYTES/4];
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int superStack;
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||
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#define STACKSIZE 10000
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int remcomStack[STACKSIZE/sizeof(int)];
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static int* stackPtr = &remcomStack[STACKSIZE/sizeof(int) - 1];
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||
|
||
/*
|
||
* In many cases, the system will want to continue exception processing
|
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* when a continue command is given.
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* oldExceptionHook is a function to invoke in this case.
|
||
*/
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||
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||
static ExceptionHook oldExceptionHook;
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||
|
||
#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.
|
||
*/
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||
const short exceptionSize[] = { 4,4,6,4,4,4,4,4,29,10,16,46,12,4,4,4 };
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||
#endif
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||
|
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#ifdef mc68332
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||
static const short exceptionSize[] = { 4,4,6,4,4,4,4,4,4,4,4,4,16,4,4,4 };
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||
#endif
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||
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||
/************* jump buffer used for setjmp/longjmp **************************/
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||
jmp_buf remcomEnv;
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||
|
||
/*************************** ASSEMBLY CODE MACROS *************************/
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||
/* */
|
||
|
||
#ifdef __HAVE_68881__
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/* do an fsave, then remember the address to begin a restore from */
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#define SAVE_FP_REGS() asm(" fsave a0@-"); \
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asm(" fmovemx fp0-fp7,_registers+72"); \
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asm(" fmoveml fpcr/fpsr/fpi,_registers+168");
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#define RESTORE_FP_REGS() \
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asm(" \n\
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fmoveml _registers+168,fpcr/fpsr/fpi \n\
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fmovemx _registers+72,fp0-fp7 \n\
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cmpl #-1,a0@ | skip frestore flag set ? \n\
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||
beq skip_frestore \n\
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frestore a0@+ \n\
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||
skip_frestore: \n\
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||
");
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||
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||
#else
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#define SAVE_FP_REGS()
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#define RESTORE_FP_REGS()
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#endif /* __HAVE_68881__ */
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||
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void return_to_super();
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void return_to_user();
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||
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||
asm("
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||
.text
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.globl _return_to_super
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_return_to_super:
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||
movel _registers+60,sp /* get new stack pointer */
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||
movel _lastFrame,a0 /* get last frame info */
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||
bra return_to_any
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||
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||
.globl _return_to_user
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||
_return_to_user:
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||
movel _registers+60,a0 /* get usp */
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||
movel a0,usp /* set usp */
|
||
movel _superStack,sp /* get original stack pointer */
|
||
|
||
return_to_any:
|
||
movel _lastFrame,a0 /* get last frame info */
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||
movel a0@+,_lastFrame /* link in previous frame */
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||
addql #8,a0 /* skip over pc, vector#*/
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||
movew a0@+,d0 /* get # of words in cpu frame */
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||
addw d0,a0 /* point to end of data */
|
||
addw d0,a0 /* point to end of data */
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||
movel a0,a1
|
||
#
|
||
# copy the stack frame
|
||
subql #1,d0
|
||
copyUserLoop:
|
||
movew a1@-,sp@-
|
||
dbf d0,copyUserLoop
|
||
");
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||
RESTORE_FP_REGS()
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||
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
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||
__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();
|
||
}
|
||
|