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/* $Id: ioctl.h,v 1.3 2003/12/09 20:10:38 arjanv Exp $
*
* linux/ioctl.h for Linux by H.H. Bergman.
*/
#ifndef _ASMI386_IOCTL_H
#define _ASMI386_IOCTL_H
/* ioctl command encoding: 32 bits total, command in lower 16 bits,
* size of the parameter structure in the lower 14 bits of the
* upper 16 bits.
* Encoding the size of the parameter structure in the ioctl request
* is useful for catching programs compiled with old versions
* and to avoid overwriting user space outside the user buffer area.
* The highest 2 bits are reserved for indicating the ``access mode''.
* NOTE: This limits the max parameter size to 16kB -1 !
*/
/*
* The following is for compatibility across the various Linux
* platforms. The i386 ioctl numbering scheme doesn't really enforce
* a type field. De facto, however, the top 8 bits of the lower 16
* bits are indeed used as a type field, so we might just as well make
* this explicit here. Please be sure to use the decoding macros
* below from now on.
*/
#define _IOC_NRBITS 8
#define _IOC_TYPEBITS 8
#define _IOC_SIZEBITS 14
#define _IOC_DIRBITS 2
#define _IOC_NRMASK ((1 << _IOC_NRBITS)-1)
#define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS)-1)
#define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS)-1)
#define _IOC_DIRMASK ((1 << _IOC_DIRBITS)-1)
#define _IOC_NRSHIFT 0
#define _IOC_TYPESHIFT (_IOC_NRSHIFT+_IOC_NRBITS)
#define _IOC_SIZESHIFT (_IOC_TYPESHIFT+_IOC_TYPEBITS)
#define _IOC_DIRSHIFT (_IOC_SIZESHIFT+_IOC_SIZEBITS)
/*
* Direction bits.
*/
#define _IOC_NONE 0U
#define _IOC_WRITE 1U
#define _IOC_READ 2U
#define _IOC(dir,type,nr,size) \
(((dir) << _IOC_DIRSHIFT) | \
((type) << _IOC_TYPESHIFT) | \
((nr) << _IOC_NRSHIFT) | \
((size) << _IOC_SIZESHIFT))
/* used to create numbers */
#define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0)
#define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size))
#define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
#define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
/* used to decode ioctl numbers.. */
#define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
#define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
#define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
#define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
/* ...and for the drivers/sound files... */
#define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)
#define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)
#define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
#define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)
#define IOCSIZE_SHIFT (_IOC_SIZESHIFT)
#endif /* _ASMI386_IOCTL_H */
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