/* include/asm-i386/rwlock.h * * Helpers used by both rw spinlocks and rw semaphores. * * Based in part on code from semaphore.h and * spinlock.h Copyright 1996 Linus Torvalds. * * Copyright 1999 Red Hat, Inc. * * Written by Benjamin LaHaise. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #ifndef _ASM_I386_RWLOCK_H #define _ASM_I386_RWLOCK_H #define RW_LOCK_BIAS 0x01000000 #define RW_LOCK_BIAS_STR "0x01000000" #define __build_read_lock(rw, helper) \ asm volatile(LOCK_PREFIX " subl $1,(%0)\n\t" \ "jns 1f\n" \ "call " helper "\n\t" \ "1:\n" \ ::"a" (rw) : "memory") #define __build_write_lock(rw, helper) \ asm volatile(LOCK_PREFIX " subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \ "jz 1f\n" \ "call " helper "\n\t" \ "1:\n" \ ::"a" (rw) : "memory") #endif