mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-23 07:20:09 +07:00
3fc2579e6f
When testing in userspace, UBSAN pointed out that shifting into the sign bit is undefined behaviour. It doesn't really make sense to ask for the highest set bit of a negative value, so just turn the argument type into an unsigned int. Some architectures (eg ppc) already had it declared as an unsigned int, so I don't expect too many problems. Link: http://lkml.kernel.org/r/20181105221117.31828-1-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
236 lines
5.9 KiB
C
236 lines
5.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _PARISC_BITOPS_H
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#define _PARISC_BITOPS_H
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#ifndef _LINUX_BITOPS_H
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#error only <linux/bitops.h> can be included directly
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#endif
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#include <linux/compiler.h>
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#include <asm/types.h>
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#include <asm/byteorder.h>
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#include <asm/barrier.h>
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#include <linux/atomic.h>
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/*
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* HP-PARISC specific bit operations
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* for a detailed description of the functions please refer
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* to include/asm-i386/bitops.h or kerneldoc
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*/
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#if __BITS_PER_LONG == 64
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#define SHIFT_PER_LONG 6
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#else
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#define SHIFT_PER_LONG 5
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#endif
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#define CHOP_SHIFTCOUNT(x) (((unsigned long) (x)) & (BITS_PER_LONG - 1))
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/* See http://marc.theaimsgroup.com/?t=108826637900003 for discussion
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* on use of volatile and __*_bit() (set/clear/change):
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* *_bit() want use of volatile.
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* __*_bit() are "relaxed" and don't use spinlock or volatile.
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*/
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static __inline__ void set_bit(int nr, volatile unsigned long * addr)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long flags;
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addr += (nr >> SHIFT_PER_LONG);
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_atomic_spin_lock_irqsave(addr, flags);
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*addr |= mask;
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_atomic_spin_unlock_irqrestore(addr, flags);
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}
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static __inline__ void clear_bit(int nr, volatile unsigned long * addr)
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{
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unsigned long mask = ~(1UL << CHOP_SHIFTCOUNT(nr));
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unsigned long flags;
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addr += (nr >> SHIFT_PER_LONG);
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_atomic_spin_lock_irqsave(addr, flags);
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*addr &= mask;
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_atomic_spin_unlock_irqrestore(addr, flags);
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}
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static __inline__ void change_bit(int nr, volatile unsigned long * addr)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long flags;
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addr += (nr >> SHIFT_PER_LONG);
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_atomic_spin_lock_irqsave(addr, flags);
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*addr ^= mask;
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_atomic_spin_unlock_irqrestore(addr, flags);
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}
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static __inline__ int test_and_set_bit(int nr, volatile unsigned long * addr)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long old;
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unsigned long flags;
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int set;
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addr += (nr >> SHIFT_PER_LONG);
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_atomic_spin_lock_irqsave(addr, flags);
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old = *addr;
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set = (old & mask) ? 1 : 0;
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if (!set)
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*addr = old | mask;
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_atomic_spin_unlock_irqrestore(addr, flags);
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return set;
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}
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static __inline__ int test_and_clear_bit(int nr, volatile unsigned long * addr)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long old;
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unsigned long flags;
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int set;
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addr += (nr >> SHIFT_PER_LONG);
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_atomic_spin_lock_irqsave(addr, flags);
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old = *addr;
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set = (old & mask) ? 1 : 0;
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if (set)
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*addr = old & ~mask;
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_atomic_spin_unlock_irqrestore(addr, flags);
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return set;
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}
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static __inline__ int test_and_change_bit(int nr, volatile unsigned long * addr)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long oldbit;
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unsigned long flags;
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addr += (nr >> SHIFT_PER_LONG);
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_atomic_spin_lock_irqsave(addr, flags);
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oldbit = *addr;
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*addr = oldbit ^ mask;
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_atomic_spin_unlock_irqrestore(addr, flags);
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return (oldbit & mask) ? 1 : 0;
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}
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#include <asm-generic/bitops/non-atomic.h>
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#ifdef __KERNEL__
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/**
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* __ffs - find first bit in word. returns 0 to "BITS_PER_LONG-1".
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* @word: The word to search
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*
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* __ffs() return is undefined if no bit is set.
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*
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* 32-bit fast __ffs by LaMont Jones "lamont At hp com".
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* 64-bit enhancement by Grant Grundler "grundler At parisc-linux org".
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* (with help from willy/jejb to get the semantics right)
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*
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* This algorithm avoids branches by making use of nullification.
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* One side effect of "extr" instructions is it sets PSW[N] bit.
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* How PSW[N] (nullify next insn) gets set is determined by the
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* "condition" field (eg "<>" or "TR" below) in the extr* insn.
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* Only the 1st and one of either the 2cd or 3rd insn will get executed.
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* Each set of 3 insn will get executed in 2 cycles on PA8x00 vs 16 or so
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* cycles for each mispredicted branch.
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*/
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static __inline__ unsigned long __ffs(unsigned long x)
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{
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unsigned long ret;
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__asm__(
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#ifdef CONFIG_64BIT
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" ldi 63,%1\n"
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" extrd,u,*<> %0,63,32,%%r0\n"
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" extrd,u,*TR %0,31,32,%0\n" /* move top 32-bits down */
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" addi -32,%1,%1\n"
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#else
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" ldi 31,%1\n"
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#endif
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" extru,<> %0,31,16,%%r0\n"
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" extru,TR %0,15,16,%0\n" /* xxxx0000 -> 0000xxxx */
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" addi -16,%1,%1\n"
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" extru,<> %0,31,8,%%r0\n"
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" extru,TR %0,23,8,%0\n" /* 0000xx00 -> 000000xx */
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" addi -8,%1,%1\n"
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" extru,<> %0,31,4,%%r0\n"
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" extru,TR %0,27,4,%0\n" /* 000000x0 -> 0000000x */
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" addi -4,%1,%1\n"
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" extru,<> %0,31,2,%%r0\n"
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" extru,TR %0,29,2,%0\n" /* 0000000y, 1100b -> 0011b */
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" addi -2,%1,%1\n"
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" extru,= %0,31,1,%%r0\n" /* check last bit */
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" addi -1,%1,%1\n"
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: "+r" (x), "=r" (ret) );
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return ret;
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}
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#include <asm-generic/bitops/ffz.h>
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/*
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* ffs: find first bit set. returns 1 to BITS_PER_LONG or 0 (if none set)
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* This is defined the same way as the libc and compiler builtin
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* ffs routines, therefore differs in spirit from the above ffz (man ffs).
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*/
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static __inline__ int ffs(int x)
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{
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return x ? (__ffs((unsigned long)x) + 1) : 0;
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}
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/*
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* fls: find last (most significant) bit set.
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* fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
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*/
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static __inline__ int fls(unsigned int x)
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{
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int ret;
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if (!x)
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return 0;
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__asm__(
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" ldi 1,%1\n"
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" extru,<> %0,15,16,%%r0\n"
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" zdep,TR %0,15,16,%0\n" /* xxxx0000 */
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" addi 16,%1,%1\n"
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" extru,<> %0,7,8,%%r0\n"
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" zdep,TR %0,23,24,%0\n" /* xx000000 */
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" addi 8,%1,%1\n"
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" extru,<> %0,3,4,%%r0\n"
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" zdep,TR %0,27,28,%0\n" /* x0000000 */
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" addi 4,%1,%1\n"
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" extru,<> %0,1,2,%%r0\n"
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" zdep,TR %0,29,30,%0\n" /* y0000000 (y&3 = 0) */
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" addi 2,%1,%1\n"
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" extru,= %0,0,1,%%r0\n"
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" addi 1,%1,%1\n" /* if y & 8, add 1 */
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: "+r" (x), "=r" (ret) );
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return ret;
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}
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#include <asm-generic/bitops/__fls.h>
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#include <asm-generic/bitops/fls64.h>
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#include <asm-generic/bitops/hweight.h>
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#include <asm-generic/bitops/lock.h>
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#include <asm-generic/bitops/sched.h>
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#endif /* __KERNEL__ */
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#include <asm-generic/bitops/find.h>
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#ifdef __KERNEL__
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#include <asm-generic/bitops/le.h>
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#include <asm-generic/bitops/ext2-atomic-setbit.h>
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#endif /* __KERNEL__ */
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#endif /* _PARISC_BITOPS_H */
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