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Re: Calling convention that gets frame pointer register clobbered
- From: Jim Wilson <wilson at specifixinc dot com>
- To: Etienne Lorrain <etienne_lorrain at yahoo dot fr>
- Cc: gcc at gcc dot gnu dot org
- Date: 05 Jan 2004 12:45:03 -0800
- Subject: Re: Calling convention that gets frame pointer register clobbered
- References: <20040105133454.45980.qmail@web11802.mail.yahoo.com>
On Mon, 2004-01-05 at 05:34, Etienne Lorrain wrote:
> I am not sure, but I think that GCC manage BLKmode objects in registers
> by having their _address_ in register.
> Just for my curiosity, a question you may know how to answer: When a
> function returns a structure (bigger than 32 bits) - does it return
> a BLKmode object?
There is no relationship between constraints and calling conventions.
They are completely different things. Using a register constraint means
that the entire object is to be loaded into the register. This is true
for all targets, regardless of what the ABI says about the object.
How a structure is returned is target dependent. It is dictated by the
target's ABI. Different targets do it different ways. Some load
BLKmode objects into a register, some load the address. This has
nothing to do with constraints.
--
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com