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Replaced "return;" statements associated with bx_guard.special_unwind_stack

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hack with longjmp() back to cpu.cc main decode loop, and added a
  check in there to return control when bx_guard.special_unwind_stack
  is set (compiling with debugger enabled only).

If in the debugger you try to execute further instructions
  (which you shouldn't), other fields need to be reset I would
  think, such as EXT and errorno, and have to make sure ESP/EIP
  are corrected properly.  Basically, this hack is only good
  for examining the current situation of a nasty fault.
This commit is contained in:
Kevin Lawton 2002-10-06 22:08:18 +00:00
parent c6350caa48
commit d7a16521c4
3 changed files with 21 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
bochs/cpu/cpu.cc
View File

@ -1,5 +1,5 @@
/////////////////////////////////////////////////////////////////////////
// $Id: cpu.cc,v 1.63 2002-10-05 14:51:25 kevinlawton Exp $
// $Id: cpu.cc,v 1.64 2002-10-06 22:08:18 kevinlawton Exp $
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001 MandrakeSoft S.A.
@ -131,6 +131,15 @@ BX_CPU_C::cpu_loop(Bit32s max_instr_count)
(void) setjmp( BX_CPU_THIS_PTR jmp_buf_env );
#endif
#if BX_DEBUGGER
// If the exception() routine has encountered a nasty fault scenario,
// the debugger may request that control is returned to it so that
// the situation may be examined.
if (bx_guard.special_unwind_stack) {
return;
}
#endif
// We get here either by a normal function call, or by a longjmp
// back from an exception() call. In either case, commit the
// new EIP/ESP, and set up other environmental fields. This code

5
bochs/cpu/cpu.h
View File

@ -1,5 +1,5 @@
/////////////////////////////////////////////////////////////////////////
// $Id: cpu.h,v 1.98 2002-10-05 14:51:25 kevinlawton Exp $
// $Id: cpu.h,v 1.99 2002-10-06 22:08:18 kevinlawton Exp $
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001 MandrakeSoft S.A.
@ -2515,7 +2515,8 @@ union {
BX_SMF void interrupt(Bit8u vector, Boolean is_INT, Boolean is_error_code,
Bit16u error_code);
#if BX_CPU_LEVEL >= 2
BX_SMF void exception(unsigned vector, Bit16u error_code, Boolean is_INT);
BX_SMF void exception(unsigned vector, Bit16u error_code, Boolean is_INT)
BX_CPP_AttrNoReturn();
#endif
BX_SMF int int_number(bx_segment_reg_t *seg);
BX_SMF void shutdown_cpu(void);

17
bochs/cpu/exception.cc
View File

@ -1,5 +1,5 @@
/////////////////////////////////////////////////////////////////////////
// $Id: exception.cc,v 1.26 2002-10-06 18:05:21 kevinlawton Exp $
// $Id: exception.cc,v 1.27 2002-10-06 22:08:18 kevinlawton Exp $
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001 MandrakeSoft S.A.
@ -806,11 +806,14 @@ BX_CPU_C::exception(unsigned vector, Bit16u error_code, Boolean is_INT)
Bit8u exception_type;
unsigned prev_errno;
invalidate_prefetch_q();
UNUSED(is_INT);
#if BX_DEBUGGER
if (bx_guard.special_unwind_stack) {
BX_INFO (("exception() returning early because special_unwind_stack is set"));
return;
}
longjmp(BX_CPU_THIS_PTR jmp_buf_env, 1); // go back to main decode loop
}
#endif
#if BX_EXTERNAL_DEBUGGER
@ -822,11 +825,7 @@ BX_CPU_C::exception(unsigned vector, Bit16u error_code, Boolean is_INT)
//trap_debugger(1);
#endif
BX_INSTR_EXCEPTION(CPU_ID, vector);
invalidate_prefetch_q();
UNUSED(is_INT);
BX_DEBUG(("exception(%02x h)", (unsigned) vector));
@ -846,7 +845,7 @@ BX_CPU_C::exception(unsigned vector, Bit16u error_code, Boolean is_INT)
#if BX_DEBUGGER
bx_guard.special_unwind_stack = true;
#endif
return;
longjmp(BX_CPU_THIS_PTR jmp_buf_env, 1); // go back to main decode loop
}
/* careful not to get here with curr_exception[1]==DOUBLE_FAULT */
@ -859,7 +858,7 @@ BX_CPU_C::exception(unsigned vector, Bit16u error_code, Boolean is_INT)
#if BX_DEBUGGER
bx_guard.special_unwind_stack = true;
#endif
return;
longjmp(BX_CPU_THIS_PTR jmp_buf_env, 1); // go back to main decode loop
}
/* ??? this is not totally correct, should be done depending on