/*
   =============================================================================
	glcinit.c -- LCD drivers for the Epson GLC controller chip
	Version 5 -- 1988-08-03 -- D.N. Lynx Crowe
	(c) Copyright 1987, 1988 -- D.N. Lynx Crowe

	GLCinit()

		Initializes the GLC.

	unsigned
	GLCcrc(row, col)
	unsigned row, col;

		Positions the GLC cursor at ('row', 'col') preparatory
		to writing text.  Returns the calculated cursor address.

	unsigned
	GLCcxy(x, y)
	unsigned x, y;

		Positions the GLC cursor at ('x', 'y') preparatory to
		writing graphics.  Returns a bit mask for the pixel.
		Leaves the cursor address in lcdcurs.
		Limits:  0 LE x LE 511,  0 LE y LE 63.

	GLCwrts(s)
	char *s;

		Writes the character string pointed to by 's' at the
		current cursor position on the LCD display.
		Cursor must start and end on the same line.
		No error checks are done.

	GLCtext(row, col, s)
	unsigned row, col;
	char *s;

		Sets the GLC cursor to ('row', 'col'), then writes the
		character string pointed to by 's'.
		Cursor must start and end on the same line.
		No error checks are done.

	GLCdisp(dsp, crs, blk1, blk2, blk3)
	short dsp, crs, blk1, blk2, blk3;

		Sets the overall display, cursor and block status values.

	GLCcurs(crs)
	short crs;

		Turns the cursor on or off.
   =============================================================================
*/

/* 
*/

#include "stddefs.h"
#include "hwdefs.h"
#include "glcdefs.h"

uint16_t	lcdbase;	/* LCD graphics base address */
uint16_t	lcdbit;		/* LCD graphics pixel bit mask */
uint16_t	lcdcol;		/* LCD text column */
uint16_t	lcdctl1;	/* LCD display control -- command */
uint16_t	lcdctl2;	/* LCD display control -- data */
uint16_t	lcdcurs;	/* LCD graphics pixel byte address */
uint16_t	lcdrow;		/* LCD text row */
uint16_t	lcdx;		/* LCD graphics x */
uint16_t	lcdy;		/* LCD graphics y */

/* GLC initialization values */

int8_t glc_is1[] = { 0x12, 0x05, 0x07, 0x54, 0x58, 0x3F, 0x55, 0x00 };
int8_t glc_is2[] = { 0x00, 0x00, 0x3F, 0x00, 0x20, 0x3F, 0x00, 0x00 };

/* 
*/

/*
   =============================================================================
	GLCdisp(dsp, crs, blk1, blk2, blk3) -- set GLC display status
	Sets the overall display, cursor and block status values.
   =============================================================================
*/

void GLCdisp(int16_t dsp, int16_t crs, int16_t blk1, int16_t blk2, int16_t blk3)
{
	register int16_t val;

	val = ((blk3 & 3) << 6) | ((blk2 & 3) << 4) | ((blk1 & 3) << 2) |
		(crs & 3);

	lcdctl1 = G_DSPCTL | (dsp & 1);
	lcdctl2 = val;

	LCD_WC = lcdctl1;
	LCD_WD = lcdctl2;

}

/*
   =============================================================================
	GLCcurs() -- turns the cursor on or off
   =============================================================================
*/

void GLCcurs(int16_t crs)
{
	lcdctl2 = (crs & 3) | (lcdctl2 & ~3);

	LCD_WC = lcdctl1;
	LCD_WD = lcdctl2;
}

/* 
*/

/*
   =============================================================================
	GLCinit() -- initialize GLC
	Initializes the GLC.
   =============================================================================
*/

void GLCinit(void)
{
	register int16_t	i;
	register int32_t ic;
	register int8_t *gp;

	lcdbase = G_PLANE2;	/* set defaults for graphics variables */
	lcdx = 0;
	lcdy = 0;
	lcdbit = 0x01;

	lcdrow = 0;		/* set default for text variables */
	lcdcol = 0;

	lcdctl1 = G_DSPCTL;
	lcdctl2 = 0;

	LCD_WC = G_INIT;	/* initialize the GLC */
	gp = &glc_is1[0];

	for (i = 0; i < 8; i++)
		LCD_WD= *gp++;

	LCD_WC = G_SETSAD;	/* setup scroll registers */
	gp = &glc_is2[0];

	for (i = 0; i < 8; i++)
		LCD_WD = *gp++;

	LCD_WC = G_HSCRL;	/* clear the horizontal scroll counter */
	LCD_WD = 0;

	LCD_WC = G_OVRLAY;	/* setup the display mode */
	LCD_WD = 0x08;

	GLCdisp(G_OFF, G_B2, G_ON, G_ON, G_OFF);

/* 
*/
	LCD_WC = G_CRSWR;	/* set cursor at (0,0) in G_PLANE1 */
	LCD_WD = G_PLANE1 & 0xFF;
	LCD_WD = (G_PLANE1 >> 8) & 0xFF;

	LCD_WC = G_CRSMRT;	/* set cursor motion forward */

	LCD_WC = G_MWRITE;	/* write zeros to GLC RAM */

	for (ic = 0; ic < 65536L; ic++)
		LCD_WD = 0;

	LCD_WC = G_CRSWR;	/* set cursor to (0,0) in G_PLANE1 */
	LCD_WD = G_PLANE1 & 0xFF;
	LCD_WD = (G_PLANE1 >> 8) & 0xFF;

	LCD_WC = G_CRSFRM;	/* setup a blinking underline cursor */
	LCD_WD = 0x04;
	LCD_WD = 0x06;

	/* enable display */

	GLCdisp(G_ON, G_B2, G_ON, G_ON, G_OFF);
}

/* 
*/

/*
   =============================================================================
	GLCcrc(row, col) -- position GLC text cursor
	Positions the GLC cursor at ('row', 'col') preparatory
	to writing text.  Returns calculated cursor address.
   =============================================================================
*/

uint16_t GLCcrc(uint16_t row, uint16_t col)
{
	uint16_t curad;

	curad = col + (row * 85);	/* calculate cursor location */

	LCD_WC = G_CRSWR;		/* send cursor address to GLC */
	LCD_WD = curad & 0xFF;
	LCD_WD = (curad >> 8) & 0xFF;

	lcdrow = row;			/* set text cursor variables */
	lcdcol = col;

	return(curad);			/* return calculated cursor address */
}

/* 
*/

/*
   =============================================================================
	GLCcxy(x, y) -- position GLC graphics cursor
	Positions the GLC cursor at ('x', 'y') preparatory to
	writing graphics.  Returns a bit mask for the pixel.
	Leaves cursor address in lcdcurs.
	Limits:  0 LE x LE 511,  0 LE y LE 63.
   =============================================================================
*/

uint16_t GLCcxy(uint16_t x, uint16_t y)
{
	register uint16_t curad, xby6;

	/* calculate cursor address */

	xby6 = x % 6;
	curad = lcdbase + (85 * (63 - y)) + (x / 6) + (xby6 >> 3);
	lcdcurs = curad;

	/* send cursor address to GLC */

	LCD_WC = G_CRSWR;
	LCD_WD = curad & 0xFF;
	LCD_WD = (curad >> 8) & 0xFF;

	/* set graphics variables */

	lcdx = x;
	lcdy = y;

	/* calculate bit mask */

	lcdbit = 0x01 << (xby6 & 0x07);

	return(lcdbit);
}

/* 
*/

/*
   =============================================================================
	GLCwrts(s) -- write text string to GLC
	Writes the character string pointed to by 's' at the
	current cursor position on the LCD display.
	Cursor must start and end on the same line.
	No error checks are done.
   =============================================================================
*/

void GLCwrts(int8_t *s)
{
	LCD_WC = G_CRSMRT;	/* set cursor motion =  right */

	LCD_WC = G_MWRITE;	/* set to write data */

	while (*s) {		/* write string to GLC */

		LCD_WD = *s++;
		lcdcol++;	/* keep column variable up to date */
	}
}

/* 
*/

/*
   =============================================================================
	GLCtext(row, col, s) -- position GLC cursor and write text
	Sets the GLC cursor to ('row', 'col'), then writes the
	character string pointed to by 's'.
	Cursor must start and end on the same line.
	No error checks are done.
   =============================================================================
*/

void GLCtext(uint16_t row, uint16_t col, int8_t *s)
{
	register uint16_t curad;

	curad = col + (row * 85);	/* calculate cursor address */

	LCD_WC = G_CRSWR;		/* send cursor address to GLC */
	LCD_WD = curad & 0xFF;
	LCD_WD = (curad >> 8) & 0xFF;

	lcdrow = row;			/* set GLC text cursor variables */
	lcdcol = col;

	LCD_WC = G_CRSMRT;		/* set cursor motion = right */

	LCD_WC = G_MWRITE;		/* set to write data */

	while (*s) {			/* write string to GLC */

		LCD_WD = *s++;
		lcdcol++;		/* keep cursor column up to date */
	}
}