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Date: Fri, 13 Nov 2015 00:28:05 +0800
From: Chen Gang <xili_gchen_5257@hotmail.com>
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Subject: Re: [Qemu-devel] [PATCH 1/4] target-tilegx: Add fpu header file
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>, qemu-devel <qemu-devel@nongnu.org>, Richard Henderson <rth@twiddle.net>

On 11/13/15 00:10=2C Peter Maydell wrote:
> On 12 November 2015 at 16:04=2C Chen Gang <xili_gchen_5257@hotmail.com> w=
rote:
>> On 11/12/15 22:34=2C Richard Henderson wrote:
>>> On 11/08/2015 06:43 AM=2C Chen Gang wrote:
>>>
>>>> +#if !defined(HOST_WORDS_BIGENDIAN)
>>>> +    /* According to float(uns)sisf2 and float(uns)sidf2 in gcc tilegx=
.md */
>>>> +    uint64_t exp : 8=3B             /* exp=2C 0x9e: 31 + TILEGX_F_EXP=
_FZERO */
>>>> +    uint64_t uiknown0 : 2=3B        /* unknown */
>>>
>>> I would really rather you didn't use bitfields=2C because of exactly th=
is sort of endianness problem.  Because=2C really=2C you can't trust this l=
ayout.  But I won't press this point=2C because it is complicated enough al=
ready.
>>>
>>
>> Because of endianess issues=2C for me=2C I don't like bit fields either.=
 But
>> I can not find any other simpler ways than current.
>=20
>> OK=2C I shall remove them.
>>
>>>> +#pragma pack(pop)
>>>
>>> Huh?  What are you attempting to do here?
>>>
>>
>> It is for matching "#pragma pack(push=2C 1)" which is above all related
>> struct/unions in this header file.
>=20
> Please don't use 'pragma pack' or bitfields. If you need to pack
> and unpack things from a target-CPU defined field use bit operations
> and/or extract32/deposit32/extract64/deposit64.
>=20

OK=2C thanks=2C although it means I have to rewrite most of code=2C and tes=
t
them again. I shall try to send patch v2 within the next week.

Thanks.
--=20
Chen Gang (=E9=99=88=E5=88=9A)

Open=2C share=2C and attitude like air=2C water=2C and life which God bless=
ed