Fix for setting/clearing breaks take 2

[John Newlin]

My previous patch had a small bug in it.  It really works this time.  ;)

-john
>
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Index: hal/common/current/ChangeLog
===================================================================
RCS file: /cvs/ecos/ecos/packages/hal/common/current/ChangeLog,v
retrieving revision 1.103
diff -c -r1.103 ChangeLog
*** hal/common/current/ChangeLog	22 Apr 2004 15:26:33 -0000	1.103
--- hal/common/current/ChangeLog	21 May 2004 22:18:31 -0000
***************
*** 1,3 ****
--- 1,13 ----
+ 2004-05-19  John Newlin <jnewlin@stretchinc.com>
+ 
+ 	* src/hal_stub.c:
+ 	(cyg_hal_gdb_interrupt) 
+ 	(cyg_hal_gdb_remove_break): Changed both to use
+ 	_read_mem_safe/__write_mem_safe for inserting a breakpoint, and
+ 	restoring the original instruction.
+ 	The Xtensa architecture (and others maybe?) can have unaligned
+ 	instructions, which caused unaligned load/store exception.
+ 	
  2004-04-22  Jani Monoses <jani@iv.ro>
  
  	 * cdl/hal.cdl :
Index: hal/common/current/src/hal_stub.c
===================================================================
RCS file: /cvs/ecos/ecos/packages/hal/common/current/src/hal_stub.c,v
retrieving revision 1.38
diff -c -r1.38 hal_stub.c
*** hal/common/current/src/hal_stub.c	6 May 2003 21:00:20 -0000	1.38
--- hal/common/current/src/hal_stub.c	21 May 2004 22:18:31 -0000
***************
*** 281,286 ****
--- 281,288 ----
  void 
  cyg_hal_gdb_interrupt (target_register_t pc)
  {
+     t_inst break_inst = HAL_BREAKINST;
+ 
      CYGARC_HAL_SAVE_GP();
  
      // Clear flag that we Continued instead of Stepping
***************
*** 290,298 ****
          cyg_hal_gdb_remove_break( (target_register_t)break_buffer.targetAddr );
  
      if (NULL == break_buffer.targetAddr) {
!         break_buffer.targetAddr = (t_inst*) pc;
!         break_buffer.savedInstr = *(t_inst*)pc;
!         *(t_inst*)pc = (t_inst)HAL_BREAKINST;
  
          __data_cache(CACHE_FLUSH);
          __instruction_cache(CACHE_FLUSH);
--- 292,306 ----
          cyg_hal_gdb_remove_break( (target_register_t)break_buffer.targetAddr );
  
      if (NULL == break_buffer.targetAddr) {
! 	// Not always safe to read/write directly to program
! 	// memory due to possibly unaligned instruction, use the
! 	// provided memory functions instead.
! 	__read_mem_safe(&break_buffer.savedInstr, (t_inst*)pc, HAL_BREAKINST_SIZE);
! 	__write_mem_safe(&break_inst, (t_inst*)pc, HAL_BREAKINST_SIZE);
! 
! 	// Save the PC where we put the break, so we can remove
! 	// it after the target takes the break.
! 	break_buffer.targetAddr = (t_inst*)pc;
  
          __data_cache(CACHE_FLUSH);
          __instruction_cache(CACHE_FLUSH);
***************
*** 308,314 ****
          return 0;
  
      if ((t_inst*)pc == break_buffer.targetAddr) {
!         *(t_inst*)pc = break_buffer.savedInstr;
          break_buffer.targetAddr = NULL;
  
          __data_cache(CACHE_FLUSH);
--- 316,323 ----
          return 0;
  
      if ((t_inst*)pc == break_buffer.targetAddr) {
! 
! 	__write_mem_safe(&break_buffer.savedInstr, (t_inst*)pc, HAL_BREAKINST_SIZE);
          break_buffer.targetAddr = NULL;
  
          __data_cache(CACHE_FLUSH);