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#ifndef _ALPHA_BITOPS_H
#define _ALPHA_BITOPS_H
/*
* Copyright 1994, Linus Torvalds.
*/
/*
* These have to be done with inline assembly: that way the bit-setting
* is guaranteed to be atomic. All bit operations return 0 if the bit
* was cleared before the operation and != 0 if it was not.
*
* To get proper branch prediction for the main line, we must branch
* forward to code at the end of this object's .text section, then
* branch back to restart the operation.
*
* bit 0 is the LSB of addr; bit 64 is the LSB of (addr+1).
*/
extern __inline__ void set_bit(unsigned long nr, void * addr)
{
unsigned long oldbit;
unsigned long temp;
unsigned int * m = ((unsigned int *) addr) + (nr >> 5);
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" and %0,%3,%2\n"
" bne %2,2f\n"
" xor %0,%3,%0\n"
" stl_c %0,%1\n"
" beq %0,3f\n"
"2:\n"
".section .text2,\"ax\"\n"
"3: br 1b\n"
".previous"
:"=&r" (temp), "=m" (*m), "=&r" (oldbit)
:"Ir" (1UL << (nr & 31)), "m" (*m));
}
extern __inline__ void clear_bit(unsigned long nr, void * addr)
{
unsigned long oldbit;
unsigned long temp;
unsigned int * m = ((unsigned int *) addr) + (nr >> 5);
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" and %0,%3,%2\n\t"
" beq %2,2f\n\t"
" xor %0,%3,%0\n\t"
" stl_c %0,%1\n\t"
" beq %0,3f\n"
"2:\n"
".section .text2,\"ax\"\n"
"3: br 1b\n"
".previous"
:"=&r" (temp), "=m" (*m), "=&r" (oldbit)
:"Ir" (1UL << (nr & 31)), "m" (*m));
}
extern __inline__ void change_bit(unsigned long nr, void * addr)
{
unsigned long temp;
unsigned int * m = ((unsigned int *) addr) + (nr >> 5);
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" xor %0,%2,%0\n\t"
" stl_c %0,%1\n\t"
" beq %0,3f\n"
".section .text2,\"ax\"\n"
"3: br 1b\n"
".previous"
:"=&r" (temp), "=m" (*m)
:"Ir" (1UL << (nr & 31)), "m" (*m));
}
extern __inline__ unsigned long test_and_set_bit(unsigned long nr, void * addr)
{
unsigned long oldbit;
unsigned long temp;
unsigned int * m = ((unsigned int *) addr) + (nr >> 5);
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" and %0,%3,%2\n"
" bne %2,2f\n"
" xor %0,%3,%0\n"
" stl_c %0,%1\n"
" beq %0,3f\n"
"2:\n"
".section .text2,\"ax\"\n"
"3: br 1b\n"
".previous"
:"=&r" (temp), "=m" (*m), "=&r" (oldbit)
:"Ir" (1UL << (nr & 31)), "m" (*m));
return oldbit != 0;
}
extern __inline__ unsigned long test_and_clear_bit(unsigned long nr, void * addr)
{
unsigned long oldbit;
unsigned long temp;
unsigned int * m = ((unsigned int *) addr) + (nr >> 5);
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" and %0,%3,%2\n\t"
" beq %2,2f\n\t"
" xor %0,%3,%0\n\t"
" stl_c %0,%1\n\t"
" beq %0,3f\n"
"2:\n"
".section .text2,\"ax\"\n"
"3: br 1b\n"
".previous"
:"=&r" (temp), "=m" (*m), "=&r" (oldbit)
:"Ir" (1UL << (nr & 31)), "m" (*m));
return oldbit != 0;
}
extern __inline__ unsigned long test_and_change_bit(unsigned long nr, void * addr)
{
unsigned long oldbit;
unsigned long temp;
unsigned int * m = ((unsigned int *) addr) + (nr >> 5);
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" and %0,%3,%2\n\t"
" xor %0,%3,%0\n\t"
" stl_c %0,%1\n\t"
" beq %0,3f\n"
".section .text2,\"ax\"\n"
"3: br 1b\n"
".previous"
:"=&r" (temp), "=m" (*m), "=&r" (oldbit)
:"Ir" (1UL << (nr & 31)), "m" (*m));
return oldbit != 0;
}
extern __inline__ unsigned long test_bit(int nr, const void * addr)
{
return 1UL & (((const int *) addr)[nr >> 5] >> (nr & 31));
}
/*
* ffz = Find First Zero in word. Undefined if no zero exists,
* so code should check against ~0UL first..
*
* Do a binary search on the bits. Due to the nature of large
* constants on the alpha, it is worthwhile to split the search.
*/
extern inline unsigned long ffz_b(unsigned long x)
{
unsigned long sum = 0;
x = ~x & -~x; /* set first 0 bit, clear others */
if (x & 0xF0) sum += 4;
if (x & 0xCC) sum += 2;
if (x & 0xAA) sum += 1;
return sum;
}
extern inline unsigned long ffz(unsigned long word)
{
unsigned long bits, qofs, bofs;
__asm__("cmpbge %1,%2,%0" : "=r"(bits) : "r"(word), "r"(~0UL));
qofs = ffz_b(bits);
__asm__("extbl %1,%2,%0" : "=r"(bits) : "r"(word), "r"(qofs));
bofs = ffz_b(bits);
return qofs*8 + bofs;
}
/*
* Find next zero bit in a bitmap reasonably efficiently..
*/
extern inline unsigned long find_next_zero_bit(void * addr, unsigned long size, unsigned long offset)
{
unsigned long * p = ((unsigned long *) addr) + (offset >> 6);
unsigned long result = offset & ~63UL;
unsigned long tmp;
if (offset >= size)
return size;
size -= result;
offset &= 63UL;
if (offset) {
tmp = *(p++);
tmp |= ~0UL >> (64-offset);
if (size < 64)
goto found_first;
if (~tmp)
goto found_middle;
size -= 64;
result += 64;
}
while (size & ~63UL) {
if (~(tmp = *(p++)))
goto found_middle;
result += 64;
size -= 64;
}
if (!size)
return result;
tmp = *p;
found_first:
tmp |= ~0UL << size;
found_middle:
return result + ffz(tmp);
}
/*
* The optimizer actually does good code for this case..
*/
#define find_first_zero_bit(addr, size) \
find_next_zero_bit((addr), (size), 0)
#ifdef __KERNEL__
#define ext2_set_bit test_and_set_bit
#define ext2_clear_bit test_and_clear_bit
#define ext2_test_bit test_bit
#define ext2_find_first_zero_bit find_first_zero_bit
#define ext2_find_next_zero_bit find_next_zero_bit
/* Bitmap functions for the minix filesystem. */
#define minix_set_bit(nr,addr) test_and_set_bit(nr,addr)
#define minix_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
#define minix_test_bit(nr,addr) test_bit(nr,addr)
#define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
#endif /* __KERNEL__ */
#endif /* _ALPHA_BITOPS_H */
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