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/*
* $Id: bitops.h,v 1.12 2000/02/09 03:28:31 davem 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__ int test_bit(int nr, __const__ volatile void *addr)
{
__const__ unsigned int *p = (__const__ unsigned int *) addr;
return ((p[nr >> 5] >> (nr & 0x1f)) & 1) != 0;
}
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 */
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