Hi all, I just wanted to bring to the attention of the list the O32 FPXX ABI proposal: https://dmz-portal.mips.com/wiki/MIPS_O32_ABI_-_FR0_and_FR1_Interlinking This is the proposal that I mentioned in commit 06e2e88292e9 "MIPS: mark O32+FP64 experimental for now". The goal is to reduce fragmentation of the O32 ABI whilst allowing use of 64b FP registers (Status.FR=1) and the MIPS SIMD Architecture (MSA) which requires them. It removes the need for the EF_MIPS_FP64 flag and instead produces code which can safely be linked with existing FP32 binaries until such time as a new FP64-using binary becomes involved (either by being the executable or a linked shared library). That is, it preserves compatibility with existing binaries whilst allowing a gradual migration towards an FPXX/FP64 world. The proposal has been discussed on the GCC development mailing list: http://gcc.1065356.n5.nabble.com/RFC-Introducing-MIPS-O32-ABI-Extension-for-FR0-and-FR1-Interlinking-td1013453.html As it affects the kernel too, now would be a good time to raise any comments or suggestions. I have written patches to implement the requirements in the kernel (handling .MIPS.abiflags, currently emulated UFR support, HWCAP flags) and will post them to the list once discussion about O32 FPXX settles down, or sooner as an RFC if people are interested in that. Thanks, Paul
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