double argument casting

[Kalle Olavi Niemitalo]

Jorge PEREZ <jorge.perez@invia.fr> writes:

> Thanks Cedric, I actually checked the ABI (SYSTEM V APPLICATION BINARY
> INTERFACE) but couldn't find any information regarding the calling
> convention when casts should be made, it also seems to differ from GCC
> to LLVM, no idea why though :(

psABI3rd.pdf (System V Application Binary Interface, SPARC®
Processor Supplement, Third Edition) page 3-14 stipulates:

# Functions pass all integer-valued arguments as words, expanding
# signed or unsigned bytes and halfwords as needed.

I understand this to mean that the caller should expand the
values.  There is similar wording on page 3P-12 of SCD.2.4.ps.Z
(SPARC Compliance Definition 2.4, 32/64 bits, August 1998),
for the 64-bit psABI:

# Each argument value of integral type smaller than an extended
# word will be widened by the caller to an extended word
# according to the signed-ness of the argument type.

But I don't know whether GCC and LLVM purport to conform to
these ABIs on SPARC.