spin_lock_irqsave的宏展開

er

Redhat9+VPC
展開前:

    spin_lock_irqsave(&devc->lock, flags);
展開后:
do { do { __asm__ __volatile__("pushfl ; popl %0":"=g" (flags): ); __asm__ __volatile__("cli": : :"memory"); } while(0);; (void)(&devc->lock); } while (0);
展開過程:
#define spin_lock_irqsave(lock, flags)        do { local_irq_save(flags); spin_lock(lock); } while (0)
#define local_irq_save(x)    __save_and_cli(x)
#define __save_and_cli(x)    do { __save_flags(x); __cli(); } while(0);
#define __save_flags(x)        __asm__ __volatile__("pushfl ; popl %0":"=g" (x): /* no input */)
#define __cli()         __asm__ __volatile__("cli": : :"memory")
#define spin_lock(lock)        (void)(lock) /* Not "unused variable". */


本文來自ChinaUnix博客，如果查看原文請點：http://blog.chinaunix.net/u/117/showart_317231.html