NEWS for MIPS ABIs

* NEWS: Announce support for new MIPS ABI extensions.
This commit is contained in:
Matthew Fortune 2015-01-06 15:06:14 +00:00
parent 8116321f65
commit 28c38448de
1 changed files with 20 additions and 0 deletions

20
NEWS
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@ -53,6 +53,26 @@ Version 2.21
* Merged gettext 0.19.3 into the intl subdirectory. This fixes building
with newer versions of bison.
* Support for MIPS o32 FPXX, FP64A and FP64 ABI Extensions.
The original MIPS o32 hard-float ABI requires an FPU where double-precision
registers overlay two consecutive single-precision registers. MIPS32R2
introduced a new FPU mode (FR=1) where double-precision registers extend the
corresponding single-precision registers which is incompatible with the
o32 hard-float ABI. The MIPS SIMD ASE and the MIPSR6 architecture both
require the use of FR=1 making a transition necessary. New o32 ABI
extensions enable users to migrate over time from the original o32 ABI
through to the updated o32 FP64 ABI. To achieve this the dynamic linker now
tracks the ABI of any loaded object and verifies that new objects are
compatible. Mode transitions will also be requested as required and
unsupportable objects will be rejected. The ABI checks include both soft and
hard float ABIs for o32, n32 and n64.
GCC 5 with GNU binutils 2.25 onwards:
It is strongly recommended that all o32 system libraries are built using the
new o32 FPXX ABI (-mfpxx) to facilitate the transition as this is compatible
with the original and all new o32 ABI extensions. Configure a MIPS GCC
compiler using --with-fp-32=xx to set this by default.
Version 2.20