Debugging with ANGEL

[Jens-Christian Lache <lache at tu-harburg dot de>]

I'm trying to debug an arm-elf program on a ARM7TDMI based
testboard with insight-5.0. I can download my own program,
but when debugging, I can not reach the breakpoint at main.

I receive the following message:

! Program received signal SIGTRAP, Trace/breakpoint trap

-> syscalls.c Line 65 
59	#ifdef ARM_RDI_MONITOR
60	
61	static inline int
62	do_AngelSWI (int reason, void * arg)
63	{
64	  int value;
65	  asm volatile ("mov r0, %1; mov r1, %2; swi %a3; mov %0, r0"
66	       : "=r" (value) /* Outputs */
67	       : "r" (reason), "r" (arg), "i" (AngelSWI) /* Inputs */
68	       : "r0", "r1", "lr"
69			/* Clobbers r0 and r1, and lr if in supervisor mode
70	*/);   return value;
71	}
72	#endif /* ARM_RDI_MONITOR */


Stack: initialise_monitor_handles
PC: 0x02018cb0

(newlib-1.8.2/newlib/libc/sys/arm/syscalls.c)

I can set breakpoints before the error occurs and step next. It looks like 
after every instruction there occurs a SWI (to do the communication with me I
guess). The line 65 in syscalls.c is executed quite often, but finally I loose
the connection and the board is deadlocked. 

When I set a breakpoint at 
 void initialise_monitor_handles(void)
the debugger shows an other strange behavior: It exectutes line 103-105:
  block[0] = (int) ":tt";
  block[2] = 3;     /* length of filename */
  block[1] = 0;     /* mode "r" */
and than it jumps back to line 103. It executes the lines one more
time, than executes line 108-110:
  block[0] = (int) ":tt";
  block[2] = 3;     /* length of filename */
  block[1] = 4;     /* mode "w" */
and jumps back to line 106:
  monitor_stdin = do_AngelSWI (AngelSWI_Reason_Open, block);
then it jumps to line 111:
  monitor_stdout = monitor_stderr = do_AngelSWI (AngelSWI_Reason_Open, block);
back to 106, line 65 and ciao bella...

Any hints? 

Jens-Christian


Jens-Christian Lache
Technische Universitaet Hamburg-Harburg
www.tu-harburg.de/~sejl1601
Mail:
lache@tu-harburg.de
lache@ngi.de
Tel.: 
+0491759610756