home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
OS/2 Shareware BBS: 10 Tools
/
10-Tools.zip
/
lxapi32.zip
/
Include
/
asm
/
semaphor.h
< prev
next >
Wrap
C/C++ Source or Header
|
2002-04-26
|
4KB
|
110 lines
/* $Id: semaphor.h,v 1.2 2002/04/26 23:09:21 smilcke Exp $ */
#ifndef _I386_SEMAPHORE_H
#define _I386_SEMAPHORE_H
/*
* SMP- and interrupt-safe semaphores..
*
* (C) Copyright 1996 Linus Torvalds
*
* Modified 1996-12-23 by Dave Grothe <dave@gcom.com> to fix bugs in
* the original code and to make semaphore waits
* interruptible so that processes waiting on
* semaphores can be killed.
* Modified 1999-02-14 by Andrea Arcangeli, split the sched.c helper
* functions in asm/sempahore-helper.h while fixing a
* potential and subtle race discovered by Ulrich Schmid
* in down_interruptible(). Since I started to play here I
* also implemented the `trylock' semaphore operation.
* 1999-07-02 Artur Skawina <skawina@geocities.com>
* Optimized "0(ecx)" -> "(ecx)" (the assembler does not
* do this). Changed calling sequences from push/jmp to
* traditional call/ret.
*
* If you would like to see an analysis of this implementation, please
* ftp to gcom.com and download the file
* /pub/linux/src/semaphore/semaphore-2.0.24.tar.gz.
*
*/
#include <asm/atomic.h>
#include <linux/spinlock.h>
struct semaphore {
atomic_t count;
int sleepers;
void * wait;
#if WAITQUEUE_DEBUG
long __magic;
#endif
};
#if WAITQUEUE_DEBUG
# define __SEM_DEBUG_INIT(name) \
, (int)&(name).__magic
#else
# define __SEM_DEBUG_INIT(name)
#endif
#define __SEMAPHORE_INITIALIZER(name,count) \
{ ATOMIC_INIT(count), 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
__SEM_DEBUG_INIT(name) }
#define __MUTEX_INITIALIZER(name) \
__SEMAPHORE_INITIALIZER(name,1)
#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
extern void sema_init (struct semaphore *sem, int val);
#if (defined(TARGET_OS2) && !defined(NOOS2LXAPI))
extern void (*init_MUTEX)(struct semaphore *sem);
extern void (*init_MUTEX_LOCKED)(struct semaphore *sem);
#else
void init_MUTEX (struct semaphore *sem);
void init_MUTEX_LOCKED (struct semaphore *sem);
#endif
void __down_failed(void /* special register calling convention */);
int __down_failed_interruptible(void /* params in registers */);
int __down_failed_trylock(void /* params in registers */);
void __up_wakeup(void /* special register calling convention */);
void __down(struct semaphore * sem);
int __down_interruptible(struct semaphore * sem);
int __down_trylock(struct semaphore * sem);
void __up(struct semaphore * sem);
/*
* This is ugly, but we want the default case to fall through.
* "down_failed" is a special asm handler that calls the C
* routine that actually waits. See arch/i386/lib/semaphore.S
*/
#if (defined(TARGET_OS2) && !defined(NOOS2LXAPI))
extern void (*down)(struct semaphore *sem);
#else
extern void down(struct semaphore * sem);
#endif
extern int down_interruptible(struct semaphore * sem);
extern int down_trylock(struct semaphore * sem);
/*
* Note! This is subtle. We jump to wake people up only if
* the semaphore was negative (== somebody was waiting on it).
* The default case (no contention) will result in NO
* jumps for both down() and up().
*/
#if (defined(TARGET_OS2) && !defined(NOOS2LXAPI))
extern void (*up)(struct semaphore *sem);
#else
extern void up(struct semaphore * sem);
#endif
#endif