[ECOS] Re: ARM arch: unknown asm insn "mrc" in v5T_semantics()

[Daniel Néri]

Mark Salter <msalter@redhat.com> writes:

>>>>>> Heiko Panther writes:
>
>> I'm targetting an ARM7 TDMI processor, and gcc 3.3.2 complains about 
>> this inline asm instruction from function arm_stub.h:v5T_semantics().
>
>>      asm volatile ("mrc  p15,0,%0,c0,c0,0\n"
>> 		  : "=r" (id) : /* no inputs */);
>
>> What's up with this insn, I can't find it in the reference. And what 
>> should I correct to make it work?
>
> Which reference? It is covered in the ARM Architectural Reference Manual.
> The instruction reads the CPU ID register and is valid for all ARM cpus.

It doesn't "compile" in Thumb mode though. I'm not sure if it helps
Heiko, but I have the following quick fix in my tree:


static int
v5T_semantics(void)
{
#ifdef CYGINT_HAL_ARM_ARCH_ARM7
    return 0;
#else
    unsigned id;

    asm volatile ("mrc  p15,0,%0,c0,c0,0\n"
		  : "=r" (id) : /* no inputs */);

    return ((id >> 16) & 0xff) >= 5;
#endif
}


Regards
  --Daniel


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