387 lines
9.9 KiB
C
387 lines
9.9 KiB
C
/* asm/bitops.h for Linux/CRIS
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*
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* TODO: asm versions if speed is needed
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*
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* All bit operations return 0 if the bit was cleared before the
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* operation and != 0 if it was not.
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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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#ifndef _CRIS_BITOPS_H
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#define _CRIS_BITOPS_H
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/* Currently this is unsuitable for consumption outside the kernel. */
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#ifdef __KERNEL__
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#include <asm/arch/bitops.h>
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#include <asm/system.h>
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#include <asm/atomic.h>
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#include <linux/compiler.h>
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/*
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* Some hacks to defeat gcc over-optimizations..
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*/
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struct __dummy { unsigned long a[100]; };
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#define ADDR (*(struct __dummy *) addr)
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#define CONST_ADDR (*(const struct __dummy *) addr)
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/*
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* set_bit - Atomically 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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* This function is atomic and may not be reordered. See __set_bit()
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* if you do not require the atomic guarantees.
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* Note that @nr may be almost arbitrarily large; this function is not
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* restricted to acting on a single-word quantity.
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*/
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#define set_bit(nr, addr) (void)test_and_set_bit(nr, addr)
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#define __set_bit(nr, addr) (void)__test_and_set_bit(nr, addr)
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/*
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* clear_bit - Clears a bit in memory
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* @nr: Bit to clear
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* @addr: Address to start counting from
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*
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* clear_bit() is atomic and may not be reordered. However, it does
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* not contain a memory barrier, so if it is used for locking purposes,
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* you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
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* in order to ensure changes are visible on other processors.
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*/
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#define clear_bit(nr, addr) (void)test_and_clear_bit(nr, addr)
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#define __clear_bit(nr, addr) (void)__test_and_clear_bit(nr, addr)
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/*
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* change_bit - Toggle a bit in memory
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* @nr: Bit to change
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* @addr: Address to start counting from
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*
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* change_bit() is atomic and may not be reordered.
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* Note that @nr may be almost arbitrarily large; this function is not
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* restricted to acting on a single-word quantity.
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*/
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#define change_bit(nr, addr) (void)test_and_change_bit(nr, addr)
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/*
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* __change_bit - Toggle a bit in memory
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* @nr: the bit to change
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* @addr: the address to start counting from
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*
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* Unlike change_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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#define __change_bit(nr, addr) (void)__test_and_change_bit(nr, addr)
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/**
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* test_and_set_bit - Set a bit and return its old value
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* @nr: Bit to set
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* @addr: Address to count from
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*
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* This operation is atomic and cannot be reordered.
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* It also implies a memory barrier.
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*/
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extern inline int test_and_set_bit(int nr, volatile unsigned long *addr)
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{
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unsigned int mask, retval;
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unsigned long flags;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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cris_atomic_save(addr, flags);
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retval = (mask & *adr) != 0;
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*adr |= mask;
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cris_atomic_restore(addr, flags);
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local_irq_restore(flags);
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return retval;
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}
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extern inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
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{
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unsigned int mask, retval;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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retval = (mask & *adr) != 0;
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*adr |= mask;
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return retval;
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}
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/*
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* clear_bit() doesn't provide any barrier for the compiler.
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*/
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#define smp_mb__before_clear_bit() barrier()
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#define smp_mb__after_clear_bit() barrier()
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/**
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* test_and_clear_bit - Clear a bit and return its old value
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* @nr: Bit to clear
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* @addr: Address to count from
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*
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* This operation is atomic and cannot be reordered.
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* It also implies a memory barrier.
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*/
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extern inline int test_and_clear_bit(int nr, volatile unsigned long *addr)
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{
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unsigned int mask, retval;
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unsigned long flags;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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cris_atomic_save(addr, flags);
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retval = (mask & *adr) != 0;
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*adr &= ~mask;
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cris_atomic_restore(addr, flags);
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return retval;
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}
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/**
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* __test_and_clear_bit - Clear a bit and return its old value
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* @nr: Bit to clear
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* @addr: Address to count from
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*
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* This operation is non-atomic and can be reordered.
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* If two examples of this operation race, one can appear to succeed
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* but actually fail. You must protect multiple accesses with a lock.
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*/
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extern inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
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{
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unsigned int mask, retval;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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retval = (mask & *adr) != 0;
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*adr &= ~mask;
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return retval;
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}
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/**
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* test_and_change_bit - Change a bit and return its old value
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* @nr: Bit to change
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* @addr: Address to count from
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*
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* This operation is atomic and cannot be reordered.
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* It also implies a memory barrier.
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*/
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extern inline int test_and_change_bit(int nr, volatile unsigned long *addr)
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{
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unsigned int mask, retval;
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unsigned long flags;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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cris_atomic_save(addr, flags);
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retval = (mask & *adr) != 0;
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*adr ^= mask;
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cris_atomic_restore(addr, flags);
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return retval;
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}
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/* WARNING: non atomic and it can be reordered! */
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extern inline int __test_and_change_bit(int nr, volatile unsigned long *addr)
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{
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unsigned int mask, retval;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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retval = (mask & *adr) != 0;
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*adr ^= mask;
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return retval;
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}
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/**
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* test_bit - Determine whether a bit is set
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* @nr: bit number to test
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* @addr: Address to start counting from
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*
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* This routine doesn't need to be atomic.
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*/
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extern inline int test_bit(int nr, const volatile unsigned long *addr)
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{
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unsigned int mask;
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unsigned int *adr = (unsigned int *)addr;
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adr += nr >> 5;
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mask = 1 << (nr & 0x1f);
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return ((mask & *adr) != 0);
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}
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/*
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* Find-bit routines..
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*/
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/*
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* Since we define it "external", it collides with the built-in
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* definition, which doesn't have the same semantics. We don't want to
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* use -fno-builtin, so just hide the name ffs.
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*/
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#define ffs kernel_ffs
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/*
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* fls: find last bit set.
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*/
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#define fls(x) generic_fls(x)
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/*
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* hweightN - returns the hamming weight of a N-bit word
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* @x: the word to weigh
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*
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* The Hamming Weight of a number is the total number of bits set in it.
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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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/**
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* find_next_zero_bit - find the first zero bit in a memory region
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* @addr: The address to base the search on
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* @offset: The bitnumber to start searching at
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* @size: The maximum size to search
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*/
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extern inline int find_next_zero_bit (const unsigned long * addr, int size, int offset)
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{
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unsigned long *p = ((unsigned long *) addr) + (offset >> 5);
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unsigned long result = offset & ~31UL;
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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 &= 31UL;
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if (offset) {
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tmp = *(p++);
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tmp |= ~0UL >> (32-offset);
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if (size < 32)
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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 -= 32;
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result += 32;
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}
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while (size & ~31UL) {
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if (~(tmp = *(p++)))
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goto found_middle;
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result += 32;
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size -= 32;
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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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* find_next_bit - find the first set bit in a memory region
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* @addr: The address to base the search on
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* @offset: The bitnumber to start searching at
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* @size: The maximum size to search
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*/
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static __inline__ int find_next_bit(const unsigned long *addr, int size, int offset)
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{
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unsigned long *p = ((unsigned long *) addr) + (offset >> 5);
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unsigned long result = offset & ~31UL;
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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 &= 31UL;
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if (offset) {
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tmp = *(p++);
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tmp &= (~0UL << offset);
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if (size < 32)
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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 -= 32;
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result += 32;
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}
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while (size & ~31UL) {
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if ((tmp = *(p++)))
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goto found_middle;
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result += 32;
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size -= 32;
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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 >> (32 - size));
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if (tmp == 0UL) /* Are any bits set? */
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return result + size; /* Nope. */
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found_middle:
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return result + __ffs(tmp);
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}
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/**
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* find_first_zero_bit - find the first zero bit in a memory region
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* @addr: The address to start the search at
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* @size: The maximum size to search
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*
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* Returns the bit-number of the first zero bit, not the number of the byte
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* containing a bit.
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*/
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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 find_first_bit(addr, size) \
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find_next_bit((addr), (size), 0)
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#define ext2_set_bit test_and_set_bit
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#define ext2_set_bit_atomic(l,n,a) test_and_set_bit(n,a)
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#define ext2_clear_bit test_and_clear_bit
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#define ext2_clear_bit_atomic(l,n,a) test_and_clear_bit(n,a)
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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_set_bit(nr,addr) test_and_set_bit(nr,addr)
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#define minix_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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extern inline int sched_find_first_bit(const unsigned long *b)
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{
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if (unlikely(b[0]))
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return __ffs(b[0]);
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if (unlikely(b[1]))
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return __ffs(b[1]) + 32;
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if (unlikely(b[2]))
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return __ffs(b[2]) + 64;
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if (unlikely(b[3]))
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return __ffs(b[3]) + 96;
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if (b[4])
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return __ffs(b[4]) + 128;
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return __ffs(b[5]) + 32 + 128;
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}
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#endif /* __KERNEL__ */
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#endif /* _CRIS_BITOPS_H */
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