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Re: How should _Decimal64 and _Decimal128 be aligned on stack?

From: "H.J. Lu" <hjl dot tools at gmail dot com>
To: "Andrew Pinski" <pinskia at gmail dot com>
Cc: "IA32 System V Application Binary Interface" <ia32-abi at googlegroups dot com>, gcc at gcc dot gnu dot org
Date: Fri, 21 Mar 2008 21:00:25 -0700
Subject: Re: How should _Decimal64 and _Decimal128 be aligned on stack?
References: <5b2c4dff-3b96-488e-9556-d84f6b65b961@i12g2000prf.googlegroups.com> <de8d50360803211737y619b91bfl307f3845aadd67ab@mail.gmail.com>

On Fri, Mar 21, 2008 at 5:37 PM, Andrew Pinski <pinskia@gmail.com> wrote:
> On Fri, Mar 21, 2008 at 5:29 PM, H.J. <hjl.tools@gmail.com> wrote:
>  > When passing _Decimal64 or _Decimal128 to a function via stack, how
>  >  should they be aligned? Currently, gcc aligns them at 4byte boundary.
>  >  Is this desirable?
>
>  Shouldn't it always be 4 byte aligned because the SysV ABI only talks
>  about word alignment?
>

DFP is beyond i386 psABI. Gcc aligns _Decimal32 to 4 byte, _Decimal64 to 8 bytes
and _Decimal128 to 16bytes. The question is what is the best alignment for them
when passing to a functions.

H.J.

Follow-Ups:
- Re: How should _Decimal64 and _Decimal128 be aligned on stack?
  - From: Ben Elliston

References:
- How should _Decimal64 and _Decimal128 be aligned on stack?
  - From: H.J.
- Re: How should _Decimal64 and _Decimal128 be aligned on stack?
  - From: Andrew Pinski

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