| #ifndef _ASM_BITOPS_H |
| /* |
| * Copyright 1992, Linus Torvalds. |
| */ |
| |
| #ifdef i386 |
| /* |
| * These have to be done with inline assembly: that way the bit-setting |
| * is guaranteed to be atomic. All bitoperations 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; |
| } |
| |
| /* |
| * 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; |
| } |
| |
| #else |
| /* |
| * For the benefit of those who are trying to port Linux to another |
| * architecture, here are some C-language equivalents. You should |
| * recode these in the native assmebly language, if at all possible. |
| * To guarantee atomicity, these routines call cli() and sti() to |
| * disable interrupts while they operate. (You have to provide inline |
| * routines to cli() and sti().) |
| * |
| * Also note, these routines assume that you have 32 bit integers. |
| * You will have to change this if you are trying to port Linux to the |
| * Alpha architecture or to a Cray. :-) |
| * |
| * C language equivalents written by Theodore Ts'o, 9/26/92 |
| */ |
| |
| extern inline int set_bit(int nr,int * addr) |
| { |
| int mask, retval; |
| |
| addr += nr >> 5; |
| mask = 1 << (nr & 0x1f); |
| cli(); |
| retval = (mask & *addr) != 0; |
| *addr |= mask; |
| sti(); |
| return retval; |
| } |
| |
| extern inline int clear_bit(int nr, int * addr) |
| { |
| int mask, retval; |
| |
| addr += nr >> 5; |
| mask = 1 << (nr & 0x1f); |
| cli(); |
| retval = (mask & *addr) == 0; |
| *addr &= ~mask; |
| sti(); |
| return retval; |
| } |
| |
| extern inline int test_bit(int nr, int * addr) |
| { |
| int mask; |
| |
| addr += nr >> 5; |
| mask = 1 << (nr & 0x1f); |
| return ((mask & *addr) != 0); |
| } |
| #endif /* i386 */ |
| #endif /* _ASM_BITOPS_H */ |