forked from luck/tmp_suning_uos_patched
87321fddae
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>
31 lines
569 B
C
31 lines
569 B
C
#ifndef __MIPS_ASM_BITREV_H__
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#define __MIPS_ASM_BITREV_H__
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#include <linux/swab.h>
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static __always_inline __attribute_const__ u32 __arch_bitrev32(u32 x)
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{
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u32 ret;
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asm("bitswap %0, %1" : "=r"(ret) : "r"(__swab32(x)));
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return ret;
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}
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static __always_inline __attribute_const__ u16 __arch_bitrev16(u16 x)
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{
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u16 ret;
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asm("bitswap %0, %1" : "=r"(ret) : "r"(__swab16(x)));
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return ret;
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}
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static __always_inline __attribute_const__ u8 __arch_bitrev8(u8 x)
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{
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u8 ret;
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asm("bitswap %0, %1" : "=r"(ret) : "r"(x));
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return ret;
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}
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#endif /* __MIPS_ASM_BITREV_H__ */
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