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https://github.com/brain-hackers/u-boot-brain
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c1d1bfa583
UBIFS requires fls(), which is not defined for arm (and some other architectures) and this patch adds it. The implementation is taken from Linux and is generic. ffs() is also defined for those that miss it. Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
156 lines
3.0 KiB
C
156 lines
3.0 KiB
C
#ifndef _LINUX_BITOPS_H
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#define _LINUX_BITOPS_H
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#include <asm/types.h>
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/*
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* ffs: find first bit set. This is defined the same way as
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* the libc and compiler builtin ffs routines, therefore
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* differs in spirit from the above ffz (man ffs).
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*/
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static inline int generic_ffs(int x)
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{
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int r = 1;
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if (!x)
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return 0;
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if (!(x & 0xffff)) {
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x >>= 16;
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r += 16;
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}
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if (!(x & 0xff)) {
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x >>= 8;
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r += 8;
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}
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if (!(x & 0xf)) {
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x >>= 4;
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r += 4;
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}
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if (!(x & 3)) {
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x >>= 2;
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r += 2;
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}
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if (!(x & 1)) {
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x >>= 1;
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r += 1;
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}
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return r;
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}
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/**
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* fls - find last (most-significant) bit set
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* @x: the word to search
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*
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* This is defined the same way as ffs.
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* Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
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*/
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static inline int generic_fls(int x)
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{
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int r = 32;
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if (!x)
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return 0;
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if (!(x & 0xffff0000u)) {
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x <<= 16;
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r -= 16;
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}
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if (!(x & 0xff000000u)) {
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x <<= 8;
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r -= 8;
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}
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if (!(x & 0xf0000000u)) {
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x <<= 4;
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r -= 4;
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}
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if (!(x & 0xc0000000u)) {
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x <<= 2;
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r -= 2;
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}
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if (!(x & 0x80000000u)) {
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x <<= 1;
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r -= 1;
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}
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return r;
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}
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/*
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* hweightN: returns the hamming weight (i.e. the number
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* of bits set) of a N-bit word
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*/
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static inline unsigned int generic_hweight32(unsigned int w)
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{
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unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555);
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res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
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res = (res & 0x0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F);
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res = (res & 0x00FF00FF) + ((res >> 8) & 0x00FF00FF);
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return (res & 0x0000FFFF) + ((res >> 16) & 0x0000FFFF);
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}
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static inline unsigned int generic_hweight16(unsigned int w)
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{
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unsigned int res = (w & 0x5555) + ((w >> 1) & 0x5555);
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res = (res & 0x3333) + ((res >> 2) & 0x3333);
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res = (res & 0x0F0F) + ((res >> 4) & 0x0F0F);
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return (res & 0x00FF) + ((res >> 8) & 0x00FF);
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}
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static inline unsigned int generic_hweight8(unsigned int w)
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{
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unsigned int res = (w & 0x55) + ((w >> 1) & 0x55);
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res = (res & 0x33) + ((res >> 2) & 0x33);
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return (res & 0x0F) + ((res >> 4) & 0x0F);
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}
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#define BIT_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
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#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
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#include <asm/bitops.h>
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/* linux/include/asm-generic/bitops/non-atomic.h */
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#ifndef __set_bit
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# define __set_bit generic_set_bit
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#endif
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#ifndef __clear_bit
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# define __clear_bit generic_clear_bit
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#endif
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#ifndef ffs
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# define ffs generic_ffs
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#endif
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#ifndef fls
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# define fls generic_fls
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#endif
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/**
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* __set_bit - Set a bit in memory
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* @nr: the bit to set
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* @addr: the address to start counting from
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*
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* Unlike set_bit(), this function is non-atomic and may be reordered.
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* If it's called on the same region of memory simultaneously, the effect
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* may be that only one operation succeeds.
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*/
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static inline void generic_set_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long mask = BIT_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
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*p |= mask;
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}
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static inline void generic_clear_bit(int nr, volatile unsigned long *addr)
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{
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unsigned long mask = BIT_MASK(nr);
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unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
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*p &= ~mask;
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}
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#endif
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