MIPS: Implement __arch_bitrev* using bitswap for MIPSr6

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Release 6 of the MIPS architecture introduced the bitswap instruction,
which reverses the bits within each byte of a word. Make use of this
instruction to implement the __arch_bitrev* functions, which should be
faster for most MIPSr6 CPUs, reduces code size slightly and allows us to
avoid the lookup table used by the generic implementation, saving 256
bytes in the kernel binary by dropping that.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13204/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

This commit is contained in:

Paul Burton

2016-05-06 13:35:03 +01:00

committed by

Ralf Baechle

parent 015aa05f53

commit 87321fddae

2 changed files with 31 additions and 0 deletions

arch/mips/Kconfig

View File

@@ -2000,6 +2000,7 @@ config CPU_MIPSR2
 config CPU_MIPSR6
 	bool
 	default y if CPU_MIPS32_R6 || CPU_MIPS64_R6
 	select HAVE_ARCH_BITREVERSE
 	select MIPS_SPRAM
 config EVA