Matthias Klose <d...@debian.org> writes: > On 06/29/2015 07:57 PM, YunQiang Su wrote: > > On Mon, 22 Jun 2015 19:02:29 +0200 Geert Stappers <stapp...@stappers.nl> > > wrote: > >> Control: retitle -1 gcc-5-mips-32-fpxx > >> Control: tag -1 patch > >> > >> > > > > Any consider of this patch? > > Please could somebody clarify, if this bumps hardware requirements to newer > CPU > versions, or makes some hardware obsolete? I know we still keep some > longsoon2 > work arounds in binutils/gcc. Is there anything more required, like > rebuilding > packages?
The transitional FP ABI extensions (FPXX, FP64A and finally FP64) are designed around compatibility so that staged migration is possible. Moving to FPXX by default is step1 to get packages away from FP32 which is the historic/current default. Moving just from FP32 to FPXX itself and keeping MIPS II as the ISA has no negative impact on users, there would be a slight change in code generation but the code would work on all systems it already works on and be compatible with all pre-built packages. As far as I can see the patch does not change the ISA but instead just modifies the scheduling to use a more recent CPU (it will equate to a 4KC instead of an R6000). There will be no MIPS32 instructions generated and the code will be 100% compatible with other pre-built packages. With this change in place then I would hope you can move to binutils 2.25, , glibc 2.21 and kernel headers 4.1 if this has not already happened. It is important that glibc is rebuilt after all the other changes so that all the new forwards compatibility features are in place. Other packages can progress more leisurely but the more rebuilds that happen the more compatible debian will be with new FPU features in modern MIPS processors. In particular this paves the way for MSA SIMD to be usable in debian in the future. Hope I didn't ramble too much, it's a very big carefully designed plan. Thanks, Matthew
