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- /*
- * $Id: bitops.h,v 1.11 1999/01/03 20:16:48 cort Exp $
- * bitops.h: Bit string operations on the ppc
- */
-
- #ifndef _PPC_BITOPS_H
- #define _PPC_BITOPS_H
-
- #include <asm/system.h>
- #include <asm/byteorder.h>
-
- extern void set_bit(int nr, volatile void *addr);
- extern void clear_bit(int nr, volatile void *addr);
- extern void change_bit(int nr, volatile void *addr);
- extern int test_and_set_bit(int nr, volatile void *addr);
- extern int test_and_clear_bit(int nr, volatile void *addr);
- extern int test_and_change_bit(int nr, volatile void *addr);
-
-
- /* Returns the number of 0's to the left of the most significant 1 bit */
- extern __inline__ int cntlzw(int bits)
- {
- int lz;
-
- asm ("cntlzw %0,%1" : "=r" (lz) : "r" (bits));
- return lz;
- }
-
- /*
- * These are if'd out here because using : "cc" as a constraint
- * results in errors from gcc. -- Cort
- * Besides, they need to be changed so we have both set_bit
- * and test_and_set_bit, etc.
- */
- #if 0
- extern __inline__ int set_bit(int nr, void * addr)
- {
- unsigned long old, t;
- unsigned long mask = 1 << (nr & 0x1f);
- unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
-
- __asm__ __volatile__(
- "1:lwarx %0,0,%3 \n\t"
- "or %1,%0,%2 \n\t"
- "stwcx. %1,0,%3 \n\t"
- "bne 1b \n\t"
- : "=&r" (old), "=&r" (t) /*, "=m" (*p)*/
- : "r" (mask), "r" (p)
- /*: "cc" */);
-
- return (old & mask) != 0;
- }
-
- extern __inline__ unsigned long clear_bit(unsigned long nr, void *addr)
- {
- unsigned long old, t;
- unsigned long mask = 1 << (nr & 0x1f);
- unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
-
- __asm__ __volatile__("\n\
- 1: lwarx %0,0,%3
- andc %1,%0,%2
- stwcx. %1,0,%3
- bne 1b"
- : "=&r" (old), "=&r" (t) /*, "=m" (*p)*/
- : "r" (mask), "r" (p)
- /*: "cc"*/);
-
- return (old & mask) != 0;
- }
-
- extern __inline__ unsigned long change_bit(unsigned long nr, void *addr)
- {
- unsigned long old, t;
- unsigned long mask = 1 << (nr & 0x1f);
- unsigned long *p = ((unsigned long *)addr) + (nr >> 5);
-
- __asm__ __volatile__("\n\
- 1: lwarx %0,0,%3
- xor %1,%0,%2
- stwcx. %1,0,%3
- bne 1b"
- : "=&r" (old), "=&r" (t) /*, "=m" (*p)*/
- : "r" (mask), "r" (p)
- /*: "cc"*/);
-
- return (old & mask) != 0;
- }
- #endif
-
- extern __inline__ unsigned long test_bit(int nr, __const__ volatile void *addr)
- {
- __const__ unsigned int *p = (__const__ unsigned int *) addr;
-
- return (p[nr >> 5] >> (nr & 0x1f)) & 1UL;
- }
-
- extern __inline__ int ffz(unsigned int x)
- {
- int n;
-
- if (x == ~0)
- return 32;
- x = ~x & (x+1); /* set LS zero to 1, other bits to 0 */
- __asm__ ("cntlzw %0,%1" : "=r" (n) : "r" (x));
- return 31 - n;
- }
-
- #ifdef __KERNEL__
-
- /*
- * ffs: find first bit set. This is defined the same way as
- * the libc and compiler builtin ffs routines, therefore
- * differs in spirit from the above ffz (man ffs).
- */
-
- #define ffs(x) generic_ffs(x)
-
- #if 0
- /* untested, someone with PPC knowledge? */
- /* From Alexander Kjeldaas <astor@guardian.no> */
- extern __inline__ int ffs(int x)
- {
- int result;
- asm ("cntlzw %0,%1" : "=r" (result) : "r" (x));
- return 32 - result; /* IBM backwards ordering of bits */
- }
- #endif
-
- /*
- * hweightN: returns the hamming weight (i.e. the number
- * of bits set) of a N-bit word
- */
-
- #define hweight32(x) generic_hweight32(x)
- #define hweight16(x) generic_hweight16(x)
- #define hweight8(x) generic_hweight8(x)
-
- #endif /* __KERNEL__ */
-
- /*
- * This implementation of find_{first,next}_zero_bit was stolen from
- * Linus' asm-alpha/bitops.h.
- */
- #define find_first_zero_bit(addr, size) \
- find_next_zero_bit((addr), (size), 0)
-
- extern __inline__ unsigned long find_next_zero_bit(void * addr,
- unsigned long size, unsigned long offset)
- {
- unsigned int * p = ((unsigned int *) addr) + (offset >> 5);
- unsigned int result = offset & ~31UL;
- unsigned int tmp;
-
- if (offset >= size)
- return size;
- size -= result;
- offset &= 31UL;
- if (offset) {
- tmp = *p++;
- tmp |= ~0UL >> (32-offset);
- if (size < 32)
- goto found_first;
- if (tmp != ~0U)
- goto found_middle;
- size -= 32;
- result += 32;
- }
- while (size >= 32) {
- if ((tmp = *p++) != ~0U)
- goto found_middle;
- result += 32;
- size -= 32;
- }
- if (!size)
- return result;
- tmp = *p;
- found_first:
- tmp |= ~0UL << size;
- found_middle:
- return result + ffz(tmp);
- }
-
-
- #define _EXT2_HAVE_ASM_BITOPS_
-
- #ifdef __KERNEL__
- /*
- * test_and_{set,clear}_bit guarantee atomicity without
- * disabling interrupts.
- */
- #define ext2_set_bit(nr, addr) test_and_set_bit((nr) ^ 0x18, addr)
- #define ext2_clear_bit(nr, addr) test_and_clear_bit((nr) ^ 0x18, addr)
-
- #else
- extern __inline__ int ext2_set_bit(int nr, void * addr)
- {
- int mask;
- unsigned char *ADDR = (unsigned char *) addr;
- int oldbit;
-
- ADDR += nr >> 3;
- mask = 1 << (nr & 0x07);
- oldbit = (*ADDR & mask) ? 1 : 0;
- *ADDR |= mask;
- return oldbit;
- }
-
- extern __inline__ int ext2_clear_bit(int nr, void * addr)
- {
- int mask;
- unsigned char *ADDR = (unsigned char *) addr;
- int oldbit;
-
- ADDR += nr >> 3;
- mask = 1 << (nr & 0x07);
- oldbit = (*ADDR & mask) ? 1 : 0;
- *ADDR = *ADDR & ~mask;
- return oldbit;
- }
- #endif /* __KERNEL__ */
-
- extern __inline__ int ext2_test_bit(int nr, __const__ void * addr)
- {
- __const__ unsigned char *ADDR = (__const__ unsigned char *) addr;
-
- return (ADDR[nr >> 3] >> (nr & 7)) & 1;
- }
-
- /*
- * This implementation of ext2_find_{first,next}_zero_bit was stolen from
- * Linus' asm-alpha/bitops.h and modified for a big-endian machine.
- */
-
- #define ext2_find_first_zero_bit(addr, size) \
- ext2_find_next_zero_bit((addr), (size), 0)
-
- extern __inline__ unsigned long ext2_find_next_zero_bit(void *addr,
- unsigned long size, unsigned long offset)
- {
- unsigned int *p = ((unsigned int *) addr) + (offset >> 5);
- unsigned int result = offset & ~31UL;
- unsigned int tmp;
-
- if (offset >= size)
- return size;
- size -= result;
- offset &= 31UL;
- if (offset) {
- tmp = cpu_to_le32p(p++);
- tmp |= ~0UL >> (32-offset);
- if (size < 32)
- goto found_first;
- if (tmp != ~0U)
- goto found_middle;
- size -= 32;
- result += 32;
- }
- while (size >= 32) {
- if ((tmp = cpu_to_le32p(p++)) != ~0U)
- goto found_middle;
- result += 32;
- size -= 32;
- }
- if (!size)
- return result;
- tmp = cpu_to_le32p(p);
- found_first:
- tmp |= ~0U << size;
- found_middle:
- return result + ffz(tmp);
- }
-
- /* Bitmap functions for the minix filesystem. */
- #define minix_set_bit(nr,addr) ext2_set_bit(nr,addr)
- #define minix_clear_bit(nr,addr) ext2_clear_bit(nr,addr)
- #define minix_test_bit(nr,addr) ext2_test_bit(nr,addr)
- #define minix_find_first_zero_bit(addr,size) ext2_find_first_zero_bit(addr,size)
-
- #endif /* _PPC_BITOPS_H */
-