[PATCH v3 1/2] MIPS r6 support
Torbjörn Granlund
tg at gmplib.org
Tue Apr 16 13:43:04 UTC 2019
YunQiang Su <syq at debian.org> writes:
The situation is just you said: it is bad.
While we have to do it like this, since it is not for make r6
performance better,
while just make it work.
The r6 is not compatible with the previous ones: it drops some instructions....
Sure.
To make it work, one needs to disable existing assembly files and
longlong.h.
Then optionally do minimal r6/mul_1.asm, r6/addmul_1.asm,
r6/submul_1.asm, or whatever else is deemed important.
We have to do so is due to that, r6 removes the HI/LO registers, and
multu/dmultu at all.
In r6, it use GPR and mulu/muhu.
So, you can even claim that r6 is different arch with the pre-r6 ones.
Indeed, no compatibility either ways means new arch.
This path is only used on new r6 architectures, the pre-R6, like R4000,
continue to use the old code.
Yes, I understand that.
Please read my last letter again and make sure you understand the points
that I make there.
--
Torbjörn
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