root/arch/parisc/include/asm/bitops.h

INCLUDED FROM

DEFINITIONS

1. set_bit
2. clear_bit
3. change_bit
4. test_and_set_bit
5. test_and_clear_bit
6. test_and_change_bit
7. __ffs
8. ffs
9. fls

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _PARISC_BITOPS_H
   3 #define _PARISC_BITOPS_H
   4 
   5 #ifndef _LINUX_BITOPS_H
   6 #error only <linux/bitops.h> can be included directly
   7 #endif
   8 
   9 #include <linux/compiler.h>
  10 #include <asm/types.h>
  11 #include <asm/byteorder.h>
  12 #include <asm/barrier.h>
  13 #include <linux/atomic.h>
  14 
  15 /*
  16  * HP-PARISC specific bit operations
  17  * for a detailed description of the functions please refer
  18  * to include/asm-i386/bitops.h or kerneldoc
  19  */
  20 
  21 #if __BITS_PER_LONG == 64
  22 #define SHIFT_PER_LONG 6
  23 #else
  24 #define SHIFT_PER_LONG 5
  25 #endif
  26 
  27 #define CHOP_SHIFTCOUNT(x) (((unsigned long) (x)) & (BITS_PER_LONG - 1))
  28 
  29 
  30 /* See http://marc.theaimsgroup.com/?t=108826637900003 for discussion
  31  * on use of volatile and __*_bit() (set/clear/change):
  32  *      *_bit() want use of volatile.
  33  *      __*_bit() are "relaxed" and don't use spinlock or volatile.
  34  */
  35 
  36 static __inline__ void set_bit(int nr, volatile unsigned long * addr)
  37 {
  38         unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
  39         unsigned long flags;
  40 
  41         addr += (nr >> SHIFT_PER_LONG);
  42         _atomic_spin_lock_irqsave(addr, flags);
  43         *addr |= mask;
  44         _atomic_spin_unlock_irqrestore(addr, flags);
  45 }
  46 
  47 static __inline__ void clear_bit(int nr, volatile unsigned long * addr)
  48 {
  49         unsigned long mask = ~(1UL << CHOP_SHIFTCOUNT(nr));
  50         unsigned long flags;
  51 
  52         addr += (nr >> SHIFT_PER_LONG);
  53         _atomic_spin_lock_irqsave(addr, flags);
  54         *addr &= mask;
  55         _atomic_spin_unlock_irqrestore(addr, flags);
  56 }
  57 
  58 static __inline__ void change_bit(int nr, volatile unsigned long * addr)
  59 {
  60         unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
  61         unsigned long flags;
  62 
  63         addr += (nr >> SHIFT_PER_LONG);
  64         _atomic_spin_lock_irqsave(addr, flags);
  65         *addr ^= mask;
  66         _atomic_spin_unlock_irqrestore(addr, flags);
  67 }
  68 
  69 static __inline__ int test_and_set_bit(int nr, volatile unsigned long * addr)
  70 {
  71         unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
  72         unsigned long old;
  73         unsigned long flags;
  74         int set;
  75 
  76         addr += (nr >> SHIFT_PER_LONG);
  77         _atomic_spin_lock_irqsave(addr, flags);
  78         old = *addr;
  79         set = (old & mask) ? 1 : 0;
  80         if (!set)
  81                 *addr = old | mask;
  82         _atomic_spin_unlock_irqrestore(addr, flags);
  83 
  84         return set;
  85 }
  86 
  87 static __inline__ int test_and_clear_bit(int nr, volatile unsigned long * addr)
  88 {
  89         unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
  90         unsigned long old;
  91         unsigned long flags;
  92         int set;
  93 
  94         addr += (nr >> SHIFT_PER_LONG);
  95         _atomic_spin_lock_irqsave(addr, flags);
  96         old = *addr;
  97         set = (old & mask) ? 1 : 0;
  98         if (set)
  99                 *addr = old & ~mask;
 100         _atomic_spin_unlock_irqrestore(addr, flags);
 101 
 102         return set;
 103 }
 104 
 105 static __inline__ int test_and_change_bit(int nr, volatile unsigned long * addr)
 106 {
 107         unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
 108         unsigned long oldbit;
 109         unsigned long flags;
 110 
 111         addr += (nr >> SHIFT_PER_LONG);
 112         _atomic_spin_lock_irqsave(addr, flags);
 113         oldbit = *addr;
 114         *addr = oldbit ^ mask;
 115         _atomic_spin_unlock_irqrestore(addr, flags);
 116 
 117         return (oldbit & mask) ? 1 : 0;
 118 }
 119 
 120 #include <asm-generic/bitops/non-atomic.h>
 121 
 122 #ifdef __KERNEL__
 123 
 124 /**
 125  * __ffs - find first bit in word. returns 0 to "BITS_PER_LONG-1".
 126  * @word: The word to search
 127  *
 128  * __ffs() return is undefined if no bit is set.
 129  *
 130  * 32-bit fast __ffs by LaMont Jones "lamont At hp com".
 131  * 64-bit enhancement by Grant Grundler "grundler At parisc-linux org".
 132  * (with help from willy/jejb to get the semantics right)
 133  *
 134  * This algorithm avoids branches by making use of nullification.
 135  * One side effect of "extr" instructions is it sets PSW[N] bit.
 136  * How PSW[N] (nullify next insn) gets set is determined by the 
 137  * "condition" field (eg "<>" or "TR" below) in the extr* insn.
 138  * Only the 1st and one of either the 2cd or 3rd insn will get executed.
 139  * Each set of 3 insn will get executed in 2 cycles on PA8x00 vs 16 or so
 140  * cycles for each mispredicted branch.
 141  */
 142 
 143 static __inline__ unsigned long __ffs(unsigned long x)
 144 {
 145         unsigned long ret;
 146 
 147         __asm__(
 148 #ifdef CONFIG_64BIT
 149                 " ldi       63,%1\n"
 150                 " extrd,u,*<>  %0,63,32,%%r0\n"
 151                 " extrd,u,*TR  %0,31,32,%0\n"   /* move top 32-bits down */
 152                 " addi    -32,%1,%1\n"
 153 #else
 154                 " ldi       31,%1\n"
 155 #endif
 156                 " extru,<>  %0,31,16,%%r0\n"
 157                 " extru,TR  %0,15,16,%0\n"      /* xxxx0000 -> 0000xxxx */
 158                 " addi    -16,%1,%1\n"
 159                 " extru,<>  %0,31,8,%%r0\n"
 160                 " extru,TR  %0,23,8,%0\n"       /* 0000xx00 -> 000000xx */
 161                 " addi    -8,%1,%1\n"
 162                 " extru,<>  %0,31,4,%%r0\n"
 163                 " extru,TR  %0,27,4,%0\n"       /* 000000x0 -> 0000000x */
 164                 " addi    -4,%1,%1\n"
 165                 " extru,<>  %0,31,2,%%r0\n"
 166                 " extru,TR  %0,29,2,%0\n"       /* 0000000y, 1100b -> 0011b */
 167                 " addi    -2,%1,%1\n"
 168                 " extru,=  %0,31,1,%%r0\n"      /* check last bit */
 169                 " addi    -1,%1,%1\n"
 170                         : "+r" (x), "=r" (ret) );
 171         return ret;
 172 }
 173 
 174 #include <asm-generic/bitops/ffz.h>
 175 
 176 /*
 177  * ffs: find first bit set. returns 1 to BITS_PER_LONG or 0 (if none set)
 178  * This is defined the same way as the libc and compiler builtin
 179  * ffs routines, therefore differs in spirit from the above ffz (man ffs).
 180  */
 181 static __inline__ int ffs(int x)
 182 {
 183         return x ? (__ffs((unsigned long)x) + 1) : 0;
 184 }
 185 
 186 /*
 187  * fls: find last (most significant) bit set.
 188  * fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
 189  */
 190 
 191 static __inline__ int fls(unsigned int x)
 192 {
 193         int ret;
 194         if (!x)
 195                 return 0;
 196 
 197         __asm__(
 198         "       ldi             1,%1\n"
 199         "       extru,<>        %0,15,16,%%r0\n"
 200         "       zdep,TR         %0,15,16,%0\n"          /* xxxx0000 */
 201         "       addi            16,%1,%1\n"
 202         "       extru,<>        %0,7,8,%%r0\n"
 203         "       zdep,TR         %0,23,24,%0\n"          /* xx000000 */
 204         "       addi            8,%1,%1\n"
 205         "       extru,<>        %0,3,4,%%r0\n"
 206         "       zdep,TR         %0,27,28,%0\n"          /* x0000000 */
 207         "       addi            4,%1,%1\n"
 208         "       extru,<>        %0,1,2,%%r0\n"
 209         "       zdep,TR         %0,29,30,%0\n"          /* y0000000 (y&3 = 0) */
 210         "       addi            2,%1,%1\n"
 211         "       extru,=         %0,0,1,%%r0\n"
 212         "       addi            1,%1,%1\n"              /* if y & 8, add 1 */
 213                 : "+r" (x), "=r" (ret) );
 214 
 215         return ret;
 216 }
 217 
 218 #include <asm-generic/bitops/__fls.h>
 219 #include <asm-generic/bitops/fls64.h>
 220 #include <asm-generic/bitops/hweight.h>
 221 #include <asm-generic/bitops/lock.h>
 222 #include <asm-generic/bitops/sched.h>
 223 
 224 #endif /* __KERNEL__ */
 225 
 226 #include <asm-generic/bitops/find.h>
 227 
 228 #ifdef __KERNEL__
 229 
 230 #include <asm-generic/bitops/le.h>
 231 #include <asm-generic/bitops/ext2-atomic-setbit.h>
 232 
 233 #endif  /* __KERNEL__ */
 234 
 235 #endif /* _PARISC_BITOPS_H */