Call __builtin_gcn_get_stack_limit and __builtin_gcn_first_call_this_thread_p
to reduce dependency on some register/layout assumptions by using the new
GCC mainline (GCC 13) builtins, if they are available. If not, the existing
code is used.
s[0:3] contain a descriptor used to set up the initial value of the
stack, but only the lower 48 bits of s[0:1] are currently used.
The reent marker is currently set in s3, but by stashing it in the
upper 16 bits of s[0:1] instead, s3 can be freed up for other purposes.
From: Andrew Stubbs <ams@codesourcery.com>
Fix a bug in which the high-part of 64-bit values are being corrupted, leading
to erroneous stack overflow errors. The problem was only that the mixed-size
calculations are being treated as signed when they should be unsigned.
These missing includes were causing build warnings, but also a real bug in
which the "size" parameter to "write" was being passed in 32-bit, whereas it
ought to be 64-bit. This led to intermittent bad behaviour.
Add support for the AMD GCN GPU architecture. This is primarily intended for
use with OpenMP and OpenACC offloading. It can also be used for stand-alone
programs, but this is intended mostly for testing the compiler and is not
expected to be useful in general.
The GPU architecture is highly parallel, and therefore Newlib must be
configured to use dynamic re-entrancy, and thread-safe malloc.
The only I/O available is a via a shared-memory interface provided by libgomp
and the gcn-run tool included with GCC. At this time this is limited to
stdout, argc/argv, and the return code.
Tobias Burnus
Kwok Cheung Yeung
Jeff Johnston
Andrew Stubbs