include/asm-ppc/bitops.h

   1 /*
   2  * $Id: bitops.h,v 1.11 1999/01/03 20:16:48 cort Exp $
   3  * bitops.h: Bit string operations on the ppc
   4  */
   5
   6 #ifndef _PPC_BITOPS_H
   7 #define _PPC_BITOPS_H
   8
   9 #include <asm/system.h>
  10 #include <asm/byteorder.h>
  11
  12 extern void set_bit(int nr, volatile void *addr);
  13 extern void clear_bit(int nr, volatile void *addr);
  14 extern void change_bit(int nr, volatile void *addr);
  15 extern int test_and_set_bit(int nr, volatile void *addr);
  16 extern int test_and_clear_bit(int nr, volatile void *addr);
  17 extern int test_and_change_bit(int nr, volatile void *addr);
  18
  19
  20 /* Returns the number of 0's to the left of the most significant 1 bit */
  21 extern __inline__  int cntlzw(int bits)
  22 {
  23         int lz;
  24
  25         asm ("cntlzw %0,%1" : "=r" (lz) : "r" (bits));
  26         return lz;
  27 }
  28
  29 /*
  30  * These are if'd out here because using : "cc" as a constraint
  31  * results in errors from gcc. -- Cort
  32  * Besides, they need to be changed so we have both set_bit
  33  * and test_and_set_bit, etc.
  34  */
  35 #if 0
  36 extern __inline__ int set_bit(int nr, void * addr)
  37 {
  38         unsigned long old, t;
  39         unsigned long mask = 1 << (nr & 0x1f);
  40         unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
  41
  42         __asm__ __volatile__(
  43                 "1:lwarx %0,0,%3 \n\t"
  44                 "or     %1,%0,%2 \n\t"
  45                 "stwcx. %1,0,%3 \n\t"
  46                 "bne    1b \n\t"
  47                 : "=&r" (old), "=&r" (t)        /*, "=m" (*p)*/
  48                 : "r" (mask), "r" (p)
  49                 /*: "cc" */);
  50
  51         return (old & mask) != 0;
  52 }
  53
  54 extern __inline__  unsigned long clear_bit(unsigned long nr, void *addr)
  55 {
  56         unsigned long old, t;
  57         unsigned long mask = 1 << (nr & 0x1f);
  58         unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
  59
  60         __asm__ __volatile__("\n\
  61 1:      lwarx   %0,0,%3
  62         andc    %1,%0,%2
  63         stwcx.  %1,0,%3
  64         bne     1b"
  65         : "=&r" (old), "=&r" (t)        /*, "=m" (*p)*/
  66         : "r" (mask), "r" (p)
  67       /*: "cc"*/);
  68
  69         return (old & mask) != 0;
  70 }
  71
  72 extern __inline__ unsigned long change_bit(unsigned long nr, void *addr)
  73 {
  74         unsigned long old, t;
  75         unsigned long mask = 1 << (nr & 0x1f);
  76         unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
  77
  78         __asm__ __volatile__("\n\
  79 1:      lwarx   %0,0,%3
  80         xor     %1,%0,%2
  81         stwcx.  %1,0,%3
  82         bne     1b"
  83         : "=&r" (old), "=&r" (t)        /*, "=m" (*p)*/
  84         : "r" (mask), "r" (p)
  85       /*: "cc"*/);
  86
  87         return (old & mask) != 0;
  88 }
  89 #endif
  90
  91 extern __inline__ unsigned long test_bit(int nr, __const__ volatile void *addr)
  92 {
  93         __const__ unsigned int *p = (__const__ unsigned int *) addr;
  94
  95         return (p[nr >> 5] >> (nr & 0x1f)) & 1UL;
  96 }
  97
  98 extern __inline__ int ffz(unsigned int x)
  99 {
 100         int n;
 101
 102         if (x == ~0)
 103                 return 32;
 104         x = ~x & (x+1);         /* set LS zero to 1, other bits to 0 */
 105         __asm__ ("cntlzw %0,%1" : "=r" (n) : "r" (x));
 106         return 31 - n;
 107 }
 108
 109 #ifdef __KERNEL__
 110
 111 /*
 112  * ffs: find first bit set. This is defined the same way as
 113  * the libc and compiler builtin ffs routines, therefore
 114  * differs in spirit from the above ffz (man ffs).
 115  */
 116
 117 #define ffs(x) generic_ffs(x)
 118
 119 #if 0
 120 /* untested, someone with PPC knowledge? */
 121 /* From Alexander Kjeldaas <astor@guardian.no> */
 122 extern __inline__ int ffs(int x)
 123 {
 124         int result;
 125         asm ("cntlzw %0,%1" : "=r" (result) : "r" (x));
 126         return 32 - result; /* IBM backwards ordering of bits */
 127 }
 128 #endif
 129
 130 /*
 131  * hweightN: returns the hamming weight (i.e. the number
 132  * of bits set) of a N-bit word
 133  */
 134
 135 #define hweight32(x) generic_hweight32(x)
 136 #define hweight16(x) generic_hweight16(x)
 137 #define hweight8(x) generic_hweight8(x)
 138
 139 #endif /* __KERNEL__ */
 140
 141 /*
 142  * This implementation of find_{first,next}_zero_bit was stolen from
 143  * Linus' asm-alpha/bitops.h.
 144  */
 145 #define find_first_zero_bit(addr, size) \
 146         find_next_zero_bit((addr), (size), 0)
 147
 148 extern __inline__ unsigned long find_next_zero_bit(void * addr,
 149         unsigned long size, unsigned long offset)
 150 {
 151         unsigned int * p = ((unsigned int *) addr) + (offset >> 5);
 152         unsigned int result = offset & ~31UL;
 153         unsigned int tmp;
 154
 155         if (offset >= size)
 156                 return size;
 157         size -= result;
 158         offset &= 31UL;
 159         if (offset) {
 160                 tmp = *p++;
 161                 tmp |= ~0UL >> (32-offset);
 162                 if (size < 32)
 163                         goto found_first;
 164                 if (tmp != ~0U)
 165                         goto found_middle;
 166                 size -= 32;
 167                 result += 32;
 168         }
 169         while (size >= 32) {
 170                 if ((tmp = *p++) != ~0U)
 171                         goto found_middle;
 172                 result += 32;
 173                 size -= 32;
 174         }
 175         if (!size)
 176                 return result;
 177         tmp = *p;
 178 found_first:
 179         tmp |= ~0UL << size;
 180 found_middle:
 181         return result + ffz(tmp);
 182 }
 183
 184
 185 #define _EXT2_HAVE_ASM_BITOPS_
 186
 187 #ifdef __KERNEL__
 188 /*
 189  * test_and_{set,clear}_bit guarantee atomicity without
 190  * disabling interrupts.
 191  */
 192 #define ext2_set_bit(nr, addr)          test_and_set_bit((nr) ^ 0x18, addr)
 193 #define ext2_clear_bit(nr, addr)        test_and_clear_bit((nr) ^ 0x18, addr)
 194
 195 #else
 196 extern __inline__ int ext2_set_bit(int nr, void * addr)
 197 {
 198         int             mask;
 199         unsigned char   *ADDR = (unsigned char *) addr;
 200         int oldbit;
 201
 202         ADDR += nr >> 3;
 203         mask = 1 << (nr & 0x07);
 204         oldbit = (*ADDR & mask) ? 1 : 0;
 205         *ADDR |= mask;
 206         return oldbit;
 207 }
 208
 209 extern __inline__ int ext2_clear_bit(int nr, void * addr)
 210 {
 211         int             mask;
 212         unsigned char   *ADDR = (unsigned char *) addr;
 213         int oldbit;
 214
 215         ADDR += nr >> 3;
 216         mask = 1 << (nr & 0x07);
 217         oldbit = (*ADDR & mask) ? 1 : 0;
 218         *ADDR = *ADDR & ~mask;
 219         return oldbit;
 220 }
 221 #endif  /* __KERNEL__ */
 222
 223 extern __inline__ int ext2_test_bit(int nr, __const__ void * addr)
 224 {
 225         __const__ unsigned char *ADDR = (__const__ unsigned char *) addr;
 226
 227         return (ADDR[nr >> 3] >> (nr & 7)) & 1;
 228 }
 229
 230 /*
 231  * This implementation of ext2_find_{first,next}_zero_bit was stolen from
 232  * Linus' asm-alpha/bitops.h and modified for a big-endian machine.
 233  */
 234
 235 #define ext2_find_first_zero_bit(addr, size) \
 236         ext2_find_next_zero_bit((addr), (size), 0)
 237
 238 extern __inline__ unsigned long ext2_find_next_zero_bit(void *addr,
 239         unsigned long size, unsigned long offset)
 240 {
 241         unsigned int *p = ((unsigned int *) addr) + (offset >> 5);
 242         unsigned int result = offset & ~31UL;
 243         unsigned int tmp;
 244
 245         if (offset >= size)
 246                 return size;
 247         size -= result;
 248         offset &= 31UL;
 249         if (offset) {
 250                 tmp = cpu_to_le32p(p++);
 251                 tmp |= ~0UL >> (32-offset);
 252                 if (size < 32)
 253                         goto found_first;
 254                 if (tmp != ~0U)
 255                         goto found_middle;
 256                 size -= 32;
 257                 result += 32;
 258         }
 259         while (size >= 32) {
 260                 if ((tmp = cpu_to_le32p(p++)) != ~0U)
 261                         goto found_middle;
 262                 result += 32;
 263                 size -= 32;
 264         }
 265         if (!size)
 266                 return result;
 267         tmp = cpu_to_le32p(p);
 268 found_first:
 269         tmp |= ~0U << size;
 270 found_middle:
 271         return result + ffz(tmp);
 272 }
 273
 274 /* Bitmap functions for the minix filesystem.  */
 275 #define minix_set_bit(nr,addr) ext2_set_bit(nr,addr)
 276 #define minix_clear_bit(nr,addr) ext2_clear_bit(nr,addr)
 277 #define minix_test_bit(nr,addr) ext2_test_bit(nr,addr)
 278 #define minix_find_first_zero_bit(addr,size) ext2_find_first_zero_bit(addr,size)
 279
 280 #endif /* _PPC_BITOPS_H */