From: Chen Gang <firstname.lastname@example.org>
To: Peter Maydell <email@example.com>
Cc: Chris Metcalf <firstname.lastname@example.org>,
Richard Henderson <email@example.com>
Subject: Re: [Qemu-devel] [PATCH 1/4] target-tilegx: Add fpu header file
Date: Fri, 13 Nov 2015 00:28:05 +0800 [thread overview]
Message-ID: <BLU436-SMTP162541DE50C7604210AC580B9120@phx.gbl> (raw)
On 11/13/15 00:10, Peter Maydell wrote:
> On 12 November 2015 at 16:04, Chen Gang <firstname.lastname@example.org> wrote:
>> On 11/12/15 22:34, Richard Henderson wrote:
>>> On 11/08/2015 06:43 AM, 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; /* exp, 0x9e: 31 + TILEGX_F_EXP_FZERO */
>>>> + uint64_t uiknown0 : 2; /* unknown */
>>> I would really rather you didn't use bitfields, because of exactly this sort of endianness problem. Because, really, you can't trust this layout. But I won't press this point, because it is complicated enough already.
>> Because of endianess issues, for me, I don't like bit fields either. But
>> I can not find any other simpler ways than current.
>> OK, I shall remove them.
>>>> +#pragma pack(pop)
>>> Huh? What are you attempting to do here?
>> It is for matching "#pragma pack(push, 1)" which is above all related
>> struct/unions in this header file.
> 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.
OK, thanks, although it means I have to rewrite most of code, and test
them again. I shall try to send patch v2 within the next week.
Chen Gang (陈刚)
Open, share, and attitude like air, water, and life which God blessed
next prev parent reply other threads:[~2015-11-12 16:25 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-08 5:42 [Qemu-devel] [PATCH 0/4] Implment fpu floating point instructions Chen Gang
2015-11-08 5:43 ` [Qemu-devel] [PATCH 1/4] target-tilegx: Add fpu header file Chen Gang
2015-11-12 14:34 ` Richard Henderson
2015-11-12 16:04 ` Chen Gang
2015-11-12 16:10 ` Peter Maydell
2015-11-12 16:28 ` Chen Gang [this message]
2015-11-08 5:44 ` [Qemu-devel] [PATCH 2/4] target-tilegx: Implement fpu single floating point Chen Gang
2015-11-12 14:36 ` Richard Henderson
2015-11-12 16:12 ` Chen Gang
2015-11-12 16:18 ` Richard Henderson
2015-11-12 16:29 ` Chen Gang
2015-11-08 5:46 ` [Qemu-devel] [PATCH 3/4] target-tilegx: Implement fpu fdouble " Chen Gang
2015-11-08 5:47 ` [Qemu-devel] [PATCH 4/4] target-tilegx: Let fpu implementation code can be built and used Chen Gang
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