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| -rw-r--r-- | pfinet/asm/bitops.h | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/pfinet/asm/bitops.h b/pfinet/asm/bitops.h new file mode 100644 index 00000000..ee339bd6 --- /dev/null +++ b/pfinet/asm/bitops.h @@ -0,0 +1,135 @@ +#ifndef _I386_BITOPS_H +#define _I386_BITOPS_H + +/* + * Copyright 1992, 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. + * + * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). + */ + +/* + * Some hacks to defeat gcc over-optimizations.. + */ +struct __dummy { unsigned long a[100]; }; +#define ADDR (*(struct __dummy *) addr) + +extern __inline__ int set_bit(int nr, void * addr) +{ + int oldbit; + + __asm__ __volatile__("btsl %2,%1\n\tsbbl %0,%0" + :"=r" (oldbit),"=m" (ADDR) + :"r" (nr)); + return oldbit; +} + +extern __inline__ int clear_bit(int nr, void * addr) +{ + int oldbit; + + __asm__ __volatile__("btrl %2,%1\n\tsbbl %0,%0" + :"=r" (oldbit),"=m" (ADDR) + :"r" (nr)); + return oldbit; +} + +extern __inline__ int change_bit(int nr, void * addr) +{ + int oldbit; + + __asm__ __volatile__("btcl %2,%1\n\tsbbl %0,%0" + :"=r" (oldbit),"=m" (ADDR) + :"r" (nr)); + return oldbit; +} + +/* + * This routine doesn't need to be atomic, but it's faster to code it + * this way. + */ +extern __inline__ int test_bit(int nr, void * addr) +{ + int oldbit; + + __asm__ __volatile__("btl %2,%1\n\tsbbl %0,%0" + :"=r" (oldbit) + :"m" (ADDR),"r" (nr)); + return oldbit; +} + +/* + * Find-bit routines.. + */ +extern inline int find_first_zero_bit(void * addr, unsigned size) +{ + int res; + + if (!size) + return 0; + __asm__(" + cld + movl $-1,%%eax + repe; scasl + je 1f + subl $4,%%edi + movl (%%edi),%%eax + notl %%eax + bsfl %%eax,%%edx + jmp 2f +1: xorl %%edx,%%edx +2: subl %%ebx,%%edi + shll $3,%%edi + addl %%edi,%%edx" + :"=d" (res) + :"c" ((size + 31) >> 5), "D" (addr), "b" (addr) + :"ax", "bx", "cx", "di"); + return res; +} + +extern inline int find_next_zero_bit (void * addr, int size, int offset) +{ + unsigned long * p = ((unsigned long *) addr) + (offset >> 5); + int set = 0, bit = offset & 31, res; + + if (bit) { + /* + * Look for zero in first byte + */ + __asm__(" + bsfl %1,%0 + jne 1f + movl $32, %0 +1: " + : "=r" (set) + : "r" (~(*p >> bit))); + if (set < (32 - bit)) + return set + offset; + set = 32 - bit; + p++; + } + /* + * No zero yet, search remaining full bytes for a zero + */ + res = find_first_zero_bit (p, size - 32 * (p - (unsigned long *) addr)); + return (offset + set + res); +} + +/* + * ffz = Find First Zero in word. Undefined if no zero exists, + * so code should check against ~0UL first.. + */ +extern inline unsigned long ffz(unsigned long word) +{ + __asm__("bsfl %1,%0" + :"=r" (word) + :"r" (~word)); + return word; +} + +#endif /* _I386_BITOPS_H */ |