/*
 * rountines to interface between internal 
 * and external notions of what the settings are
 */


# include "setup.h"

# define HIGHBYTE 0xff00

/*
 * Micro Decision specific offsets
 */

# define BIOS		0xf200
# define REVISION	(bios [0x3f]) /* REV byte */

/*
 * revision numbers
 */


# define MINIMUM	0x20	/* minimum acceptable rev. level */
# define MD11 		0x40


# define RAMDATY	0x42
# define SET		0x52

/*
 * offsets from ramdaty
 */


# define CBAUDOFF	(-6)
# define PBAUDOFF	(-5)
# define OLDDFLAG	(11)
# define NEWDFLAG	(0x12)



/*
 * bits
 */

# define HARDBIT	(1 << 4)
# define CENTBIT	(1 << 5)

/*
 * stuff having to do with the revision number
 */

# define REVISION	(bios [0x3f]) /* offset to REV byte */
# define MINIMUM	0x20	/* minimum acceptable rev. level */

static unsigned dflag = 0;

/*
 * block attempts to use with old versions of the system
 */

version ()
	{
	if (REVISION < MINIMUM)
		fatal ("Old version of CP/M\r\n$");

	if (REVISION >= MD11)
		dflag = NEWDFLAG;
	else
		dflag = OLDDFLAG;
	}

/*
 * determine the memory address of the BIOS
 * in memory
 */

findsys ()
	{
	unsigned *i;

	i = 1;
	bios = *i & HIGHBYTE;

	i = bios + RAMDATY;
	ramdaty = *i;
	}


/*
 * read the settings 
 * always from the currently running bios
 */

readsettings ()
	{
	cbaud = ramdaty [CBAUDOFF] % NBAUD;
	pbaud = ramdaty [PBAUDOFF] % NBAUD;


	if (ramdaty [dflag] & CENTBIT)
		ptype = CENTRONICS;
	else
		ptype = SERIAL;


	if (ramdaty [dflag] & HARDBIT)
		protocol = HARDHAND;
	else
		protocol = XONXOFF;
	}

writesettings (a)
	unsigned char *a;
	{
	a [CBAUDOFF] = cbaud;
	a [PBAUDOFF] = pbaud;

	a [dflag] &= ~(CENTBIT | HARDBIT);

	if (protocol == HARDHAND)
		a [dflag] |= HARDBIT;

	if (ptype == CENTRONICS)
		a [dflag] |= CENTBIT;
	}

softset ()
	{
	writesettings (ramdaty);
	bioset ();	/* call the bios to have appropriate settings made */
	}

hardset ()
	{
	biosread ();
	writesettings (ramdaty + (unsigned) biosbuf - (unsigned) bios);
	bioswrite ();
	}

sysinit ()
	{
	findsys ();
	version ();
	}