Re: [Qemu-devel] [PATCH 3/4] hw/registerfields: add 64-bit extract/deposit macros

[Philippe Mathieu-Daudé]

Hi Francisco,

On 12/13/2017 06:37 PM, francisco iglesias wrote:
> On 13 December 2017 at 06:17, Philippe Mathieu-Daudé <address@hidden>
> wrote:
[...]
>>  /* Extract a field from an array of registers */
[...]
>> +#define FIELD_DP64(storage, reg, field, val) ({
>>  \
>> +    struct {
>> \
>> +        unsigned int v:R_ ## reg ## _ ## field ## _LENGTH;
>> \
>>
> 
> I'm just wondering if 'v' above maybe should be uint64_t? The size of
> unsigned int seems to be 'implementation defined' but I would guess 32 bits
> is not unsual. Basically wouldn't a field length > 32 above be problematic?

Good remark...

As per the standard bitfields access must be per 'unsigned'.
So with a LP64 data model we have sizeof(unsigned) = 32-bit, I wonder
how the compiler behaves.

I added the debian-win32 docker image to tests this kind of regressions,
but it seems the current toolchain used (mingw-w64) is now only a LLP64
model (I still need to verify).

I remember I somewhere have a Linux/X32 docker suite to test this
series. I'll give it a try (I doubt before this week-end).

Regards,

Phil.

>> +    } v = { .v = val };
>>  \
>> +    uint64_t d;
>>  \
>> +    d = deposit64((storage), R_ ## reg ## _ ## field ## _SHIFT,
>>  \
>> +                  R_ ## reg ## _ ## field ## _LENGTH, v.v);
>>  \
>> +    d; })
>>
>>  /* Deposit a field to array of registers.  */
>>  #define ARRAY_FIELD_DP32(regs, reg, field, val)
>>  \
>> --
>> 2.15.1

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