SPARC _ISR_Handler questions
Aleix Conchillo Flaqué
aconchillo at ieec.fcr.es
Fri Mar 17 15:05:06 UTC 2006
regarding my second question, I've just read about
CPU_ISR_PASSES_FRAME_POINTER. If it is defined with a 1 value then
the ISR_Handler_entry has a second parameter to the interrupt stack
In the case of SPARC, it is defined as (in cpukit/score/cpu/sparc/
#define CPU_ISR_PASSES_FRAME_POINTER 0
Does this means that the second argument (%o1) in cpu_asm.S could be
Thanks in advance... again.
On 17 Mar 2006, at 14:54, Aleix Conchillo Flaqué wrote:
> I'm trying to implement my own _ISR_Handler (without threading or
> context switching) and I'm looking the RTEMS _ISR_Handler
> (cpu_asm.S) code. There two things I don't understand:
> 1. At the beginning of the routine, the %l1 (PC) is saved into %l6,
> but %l6 I think it is not used anymore. Why it needs to be keeped?
> Or... where it is used?
> 2. When calling the user's handler (call %g4, 0), one argument must
> be given in %o0 which is the vector number. This is fine as the
> ISR_Handler_entry type is defined with this argument. But a second
> argument (%o1) is passed, more concretelly the code reads: o1 = 2nd
> arg = address of the ISF WAS LOADED... I don't see how the user's
> handler know about this argument. I don't understand why is it passed.
> Thanks in advance.
> Best regards,
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