#ifndef __PAB_H__
#define __PAB_H__

/*
	Defines to handle the PAB (peripheral access block) by 
	emulated device DSRS.  
	
	The PAB holds information sent to the DSR describing the
	device, filename, record, operation, etc., used in an
	I/O request.
	
	PABs are stored in the VDP RAM, and the emulated device code accesses
	the VDP RAM directly.  We must synchronize the VDP with the changes we
	make to it, so that the screen will be updated as necessary.
*/

/*	File operations (byte 0, opcode)*/
enum
{
	f_open,
	f_close,
	f_read,
	f_write,
	f_seek,
	f_load,
	f_save,
	f_delete,
	f_scratch,
	f_status
};

/*	File open codes (byte 1, pflags) */
enum
{
	m_openmode = 3 << 1,
	m_update = 0 << 1,
	m_output = 1 << 1,
	m_input = 2 << 1,
	m_append = 3 << 1
};

/*	Flags set for types of file access (byte 1, pflags)
	(0x80 never really used) */
enum
{
	fp_program = 0x80,
	fp_variable = 0x10,
	fp_internal = 0x8,
	fp_relative = 0x1
};

/*	Error codes (byte 1, pflags)*/
enum
{
	m_error	= 0x7 << 5,

	e_baddevice = 0x0,
	e_readonly = 1 << 5,
	e_badopenmode = 2 << 5,
	e_illegal = 3 << 5,
	e_outofspace = 4 << 5,
	e_endoffile	= 5 << 5,
	e_hardwarefailure = 6 << 5,
	e_badfiletype = 7 << 5
};

/*	Status codes */
enum
{
	st_filenotfound = 0x80,
	st_readonly = 0x40,
	st_internal = 0x10,
	st_program = 8,
	st_variable = 4,
	st_diskfull = 2,
	st_eof = 1
};


/*	This maps directly onto the VDP */
typedef struct
{
	u8	opcode;		/* file operation (f_xxx) */
	u8	pflags;		/* file access code (fp_xxx) + open mode (m_xxx) */
	u16	addr;		/* VDP record address */
	u8	preclen;	/* file record length */
	u8	charcount;	/* characters used in record */
	u16	recnum;		/* current record (seek position) */
	u8	scrnoffs;	/* screen offset (for CSx) */
	u8	namelen;	/* length of filename following */
	u8	name[0];	/* filename */
}	pabrec;

//extern	pabrec	*pabaddr;	/* VDP location of current PAB */

#endif