Re: [PATCH v2 5/5] tests/tcg: add user version of dumb-as-bricks semiconsole test

[Richard Henderson]

On 1/8/20 12:27 AM, Alex Bennée wrote:
> 
> Richard Henderson <address@hidden> writes:
> 
>> On 12/21/19 12:22 AM, Alex Bennée wrote:
>>> +#if defined(__arm__)
>>> +    register uintptr_t t asm("r0") = type;
>>> +    register uintptr_t a0 asm("r1") = arg0;
>>> +    asm("svc 0xab"
>>> +        : "=r" (t)
>>> +        : "r" (t), "r" (a0));
>>
>> This is the #ifdef __thumb__ svc code.  Are you enforcing that with
>> command-line arguments?
> 
> No it is dealing with aarch64 vs 32 bit and the __arm__ is a compiler
> symbol. 

I know that.  But you're obviously assuming that the arm compiler is defaulting
to thumb mode, not arm mode, otherwise this doesn't work.

You need to test

#ifdef __arm__
# ifdef __thumb__
#  define SVC  "svc 0xab"
# else
#  define SVC  "svc 0x123456"
# endif
    register ...
    asm(SVC : ...);
#else
    // aarch64
#endif

And run the compiler with -mthumb and -marm to test both.


r~