Re: [Qemu-devel] [PATCH] target/m68k: Change fpu_rom from const static array to switch

[Laurent Vivier]

Le 04/09/2017 à 15:54, Kamil Rytarowski a écrit :
> On 04.09.2017 02:27, Philippe Mathieu-Daudé wrote:
>> On 09/03/2017 02:05 PM, Laurent Vivier wrote:
>>> Le 03/09/2017 à 18:31, Kamil Rytarowski a écrit :
>>>> GCC 4.7.2 on SunOS reports that the values assigned to array members
>>>> are not
>>>> real constants:
>>>>
>>>> target/m68k/fpu_helper.c:32:5: error: initializer element is not
>>>> constant
>>>> target/m68k/fpu_helper.c:32:5: error: (near initialization for
>>>> 'fpu_rom[0]')
>>>> rules.mak:66: recipe for target 'target/m68k/fpu_helper.o' failed
>>>>
>>>> Convert the array to switch() to workaround the issue.
>>>
>>> I don't like the idea. It's really an array and should be managed as an
>>> array.
>>
>> I agree with Laurent.
>>
>>>
>>> Could you try to use make_floatx80_init() instead of make_floatx80() ?
>>
>> I guess the problem comes from the macro which cast as not const:
>>
>> #define make_floatx80(exp, mant) ((floatx80) { mant, exp })
>>
> 
> Adding const to make_floatx80 - ((const floatx80) { mant, exp }) - does
> not fix the problem.
> 
>> make_floatx80_init() doesn't cast so it might work,
>> else we could add a macro such const_floatx80():
>>
>> #define const_floatx80(exp, mant) ((const floatx80) { mant, exp })
> 
> Switching make_floatx80() to make_floatx80_init() in works.
> 
> How about floatx80_zero, floatx80_one etc? We cannot translate them to
> make_floatx80_init() as this breaks in other parts of the code in
> functions like:
> 
> void helper_fldpi_ST0(CPUX86State *env)
> {
>     ST0 = floatx80_pi;
> }
> 
> -- target/i386/fpu_helper.c
> 

You can:

either replace the "#define floatx80_pi make_floatx80(...)" by a "const
floatx80 floatx80_pi = make_floatx80_init(...)"

or replace all the macros in the m68k/fpu_helper.c array by
make_floatx80_init(...)

Thanks,
Laurent

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