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https://github.com/smaeul/u-boot.git
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726a802fda
Since ARMv5, the clz instruction allows for efficient implementation of ffs/fls with builtins. Until ARMv7 (with Thumb-2), this instruction is only available in ARM mode. LTO makes it difficult to force specific functions to be in ARM mode, as it is effectively a form of very aggressive inlining. To work around this, fls/ffs are implemented in assembly for ARMv5 and ARMv6 when compiling U-Boot in Thumb mode. Overall, this saves around 75 bytes per call. This code is synced with v5.15 of the Linux kernel. Signed-off-by: Sean Anderson <sean.anderson@seco.com> Reviewed-by: Tom Rini <trini@konsulko.com>
211 lines
4.9 KiB
C
211 lines
4.9 KiB
C
/*
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* Copyright 1995, Russell King.
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* Various bits and pieces copyrights include:
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* Linus Torvalds (test_bit).
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*
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* bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
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*
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* Please note that the code in this file should never be included
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* from user space. Many of these are not implemented in assembler
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* since they would be too costly. Also, they require priviledged
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* instructions (which are not available from user mode) to ensure
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* that they are atomic.
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*/
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#ifndef __ASM_ARM_BITOPS_H
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#define __ASM_ARM_BITOPS_H
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#if __LINUX_ARM_ARCH__ < 5
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#include <asm-generic/bitops/__ffs.h>
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#include <asm-generic/bitops/__fls.h>
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#include <asm-generic/bitops/fls.h>
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#else
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#define PLATFORM_FFS
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#define PLATFORM_FLS
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#if !IS_ENABLED(CONFIG_HAS_THUMB2) && CONFIG_IS_ENABLED(SYS_THUMB_BUILD)
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unsigned long __fls(unsigned long word);
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unsigned long __ffs(unsigned long word);
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int fls(unsigned int x);
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int ffs(int x);
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#else
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#include <asm-generic/bitops/builtin-__fls.h>
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#include <asm-generic/bitops/builtin-__ffs.h>
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#include <asm-generic/bitops/builtin-fls.h>
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#include <asm-generic/bitops/builtin-ffs.h>
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#endif
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#endif
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#include <asm-generic/bitops/fls64.h>
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#ifdef __KERNEL__
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#ifndef __ASSEMBLY__
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#include <linux/bitops.h>
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#endif
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#include <asm/proc-armv/system.h>
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#define smp_mb__before_clear_bit() do { } while (0)
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#define smp_mb__after_clear_bit() do { } while (0)
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/*
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* Function prototypes to keep gcc -Wall happy.
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*/
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extern void set_bit(int nr, volatile void * addr);
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extern void clear_bit(int nr, volatile void * addr);
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extern void change_bit(int nr, volatile void * addr);
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static inline void __change_bit(int nr, volatile void *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 int __test_and_set_bit(int nr, volatile void *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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unsigned long old = *p;
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*p = old | mask;
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return (old & mask) != 0;
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}
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static inline int test_and_set_bit(int nr, volatile void * addr)
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{
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unsigned long flags = 0;
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int out;
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local_irq_save(flags);
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out = __test_and_set_bit(nr, addr);
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local_irq_restore(flags);
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return out;
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}
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static inline int __test_and_clear_bit(int nr, volatile void *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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unsigned long old = *p;
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*p = old & ~mask;
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return (old & mask) != 0;
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}
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static inline int test_and_clear_bit(int nr, volatile void * addr)
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{
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unsigned long flags = 0;
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int out;
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local_irq_save(flags);
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out = __test_and_clear_bit(nr, addr);
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local_irq_restore(flags);
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return out;
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}
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extern int test_and_change_bit(int nr, volatile void * addr);
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static inline int __test_and_change_bit(int nr, volatile void *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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unsigned long old = *p;
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*p = old ^ mask;
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return (old & mask) != 0;
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}
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/*
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* This routine doesn't need to be atomic.
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*/
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static inline int test_bit(int nr, const void * addr)
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{
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return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
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}
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static inline int __ilog2(unsigned int x)
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{
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return fls(x) - 1;
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}
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#define ffz(x) __ffs(~(x))
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static inline int find_next_zero_bit(void *addr, int size, int offset)
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{
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unsigned long *p = ((unsigned long *)addr) + (offset / BITS_PER_LONG);
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unsigned long result = offset & ~(BITS_PER_LONG - 1);
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset &= (BITS_PER_LONG - 1);
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if (offset) {
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tmp = *(p++);
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tmp |= ~0UL >> (BITS_PER_LONG - offset);
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if (size < BITS_PER_LONG)
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goto found_first;
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if (~tmp)
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goto found_middle;
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size -= BITS_PER_LONG;
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result += BITS_PER_LONG;
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}
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while (size & ~(BITS_PER_LONG - 1)) {
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tmp = *(p++);
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if (~tmp)
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goto found_middle;
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result += BITS_PER_LONG;
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size -= BITS_PER_LONG;
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}
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if (!size)
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return result;
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tmp = *p;
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found_first:
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tmp |= ~0UL << size;
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found_middle:
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return result + ffz(tmp);
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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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#define hweight32(x) generic_hweight32(x)
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#define hweight16(x) generic_hweight16(x)
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#define hweight8(x) generic_hweight8(x)
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#define find_first_zero_bit(addr, size) \
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find_next_zero_bit((addr), (size), 0)
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#define ext2_set_bit test_and_set_bit
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#define ext2_clear_bit test_and_clear_bit
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#define ext2_test_bit test_bit
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#define ext2_find_first_zero_bit find_first_zero_bit
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#define ext2_find_next_zero_bit find_next_zero_bit
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/* Bitmap functions for the minix filesystem. */
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#define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
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#define minix_set_bit(nr,addr) set_bit(nr,addr)
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#define minix_test_and_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
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#define minix_test_bit(nr,addr) test_bit(nr,addr)
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#define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
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#endif /* __KERNEL__ */
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#endif /* _ARM_BITOPS_H */
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