Link must point to http://lxr.linux.no/source/include/asm-i386/semaphore.h?v=2.6.10#L105 Sorry for that. Regards, om. On 4/13/06, Om Narasimhan <om.turyx@xxxxxxxxx> wrote: > Hi, > In the below code fragment, how does this escape an infinite loop > (line 116 down)? > From linux-2.6.16/include/asm-i386/semaphore.h ( > http://lxr.linux.no/ident?v=2.6.10;i=down ) > 105 static inline void down(struct semaphore * sem) > 106 { > might_sleep(); > __asm__ __volatile__( > "# atomic down operation\n\t" > LOCK "decl %0\n\t" /* --sem->count */ // locked and decremented. > "js 2f\n" // if sign is set jump to 2: > "1:\n" > LOCK_SECTION_START("") // starts a new section in elf, what > does this mean? > "2:\tlea %0,%%eax\n\t" // loads &sem (==&sem->count) into eax. > "call __down_failed\n\t" // this eventually returns when sem is acquired > 116 "jmp 1b\n" // goes back to 1: ... how would this function > ever return? > 117 LOCK_SECTION_END > :"=m" (sem->count) > : > :"memory","ax"); > } > > Any pointers/ideas? I checked the man pages of as. I did not quite > follow the .previous...etc directives. > > Regards, > Om. > -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
