Re: [Qemu-devel] [Qemu-ppc] [PATCH for-1.1 0/3] tcg/ppc: AREG0 support and Darwin fixes

[Andreas Färber]

Am 08.05.2012 21:42, schrieb Alexander Graf:
> 
> On 08.05.2012, at 21:29, Andreas Färber wrote:
> 
>> On patch 3/3 he didn't like my alignment macro. I don't have a better
>> one though, suggestions or patches welcome. Ideal might be some
>> ROUND_TO_ODD() macro, but the problem is that for Darwin/AIX where it's
>> no-op it shouldn't result in a "statement without effect" warning.
>> Therefore my do { } while (0) as opposed to ir = MACRO(ir).
> 
> static inline int round_reg_i64(int input_reg)
> {
> #ifdef WHATEVER_CONDITION
>     if (input_reg % 2) {
>         reg++;
>     }
> #endif
> 
>     return reg;
> }
> 
> [...]
> 
>   ir = round_reg_i64(ir);

I think he didn't like the mod check either but the suggestion
<malc> [...] reg += reg & TCG_TARGET_CALL_ALIGN_ARGS [...]
doesn't work well when TCG_TARGET_CALL_ALIGN_ARGS is undefined.
And defining it with value 0 seems unsafe to me.

What about the following? (untested)

static inline int tcg_target_call_align_i64_reg(int reg)
{
#ifdef TCG_TARGET_CALL_ALIGN_ARGS
    /* Round up to next odd register */
    return (reg & ~1) + 1;
#else
    return reg;
#endif
}

Andreas

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