/* simple low-level device driver for a KS0108 controlled LCD 
 *
 * 29.03.06 - new version for TinyMips
 * 13.10.00 - first version, copied from Claas' graphics.c
 */

#include "ks0108.h"


// fixed address for the LCDAdapter subdesign
//
//#define BASEADDR 0x00080000
#define BASEADDR 0xa0080000


// bits 0..7 connected to display D0..D7, bit 8 connected to RS, etc.
//
#define DATA_MASK   0x00ff
#define RS_MASK     0x0100
#define RW_MASK     0x0200       
#define CHIP1_MASK  0x0400
#define CHIP2_MASK  0x0800
#define NR_MASK     0x1000
#define ENAMASK     0x2000

// because the chip-selects are active low, these appear inverted...
#define CHIP1       0x0800
#define CHIP2       0x0400

#define DISPLAYON   0x103e
#define SETPAGEADR  0x10b0
#define SETBYTEADR  0x1040
#define SETSTARTADR 0x10c0
#define WRITE       0x1100

int internalColor = 1;
int xpos = 0;
int ypos = 0;
int chipselect = CHIP1;

unsigned char charset[128][7] = {
  { 0,0,0,0,0,0,0 },		// 0
  { 0,0,0,0,0,0,0 },		// 1
  { 0,0,0,0,0,0,0 },		// 2
  { 0,0,0,0,0,0,0 },		// 3
  { 0,0,0,0,0,0,0 },		// 4
  { 0,0,0,0,0,0,0 },		// 5
  { 0,0,0,0,0,0,0 },		// 6
  { 0,0,0,0,0,0,0 },		// 7
  { 0,0,0,0,0,0,0 },		// 8
  { 0,0,0,0,0,0,0 },		// 9
  { 0,0,0,0,0,0,0 },		// 10
  { 0,0,0,0,0,0,0 },		// 11
  { 0,0,0,0,0,0,0 },		// 12
  { 0,0,0,0,0,0,0 },		// 13
  { 0,0,0,0,0,0,0 },		// 14
  { 0,0,0,0,0,0,0 },		// 15
  { 0,0,0,0,0,0,0 },		// 16
  { 0,0,0,0,0,0,0 },		// 17
  { 0,0,0,0,0,0,0 },		// 18
  { 0,0,0,0,0,0,0 },		// 19
  { 0,0,0,0,0,0,0 },		// 20
  { 0,0,0,0,0,0,0 },		// 21
  { 0,0,0,0,0,0,0 },		// 22
  { 0,0,0,0,0,0,0 },		// 23
  { 0,0,0,0,0,0,0 },		// 24
  { 0,0,0,0,0,0,0 },		// 25
  { 0,0,0,0,0,0,0 },		// 26
  { 0,0,0,0,0,0,0 },		// 27
  { 0,0,0,0,0,0,0 },		// 28
  { 0,0,0,0,0,0,0 },		// 29
  { 0,0,0,0,0,0,0 },		// 30
  { 0,0,0,0,0,0,0 },		// 31
  { 3, 0, 0, 0, 0, 0, 0 },	// Space
  { 3, 47, 0, 0, 0, 0, 0 }, 	// !
  { 4, 3, 0, 3, 0, 0, 0 }, 	// "
  { 6, 20, 62, 20, 62, 20, 0 }, // #
  { 6, 4, 42, 107, 42, 16, 0 }, // $
  { 6, 38, 22, 8, 52, 50, 0 }, 	// %
  { 6, 26, 37, 37, 26, 40, 0 }, // &
  { 3, 2, 1, 0, 0, 0, 0 }, 	// '
  { 3, 30, 33, 0, 0, 0, 0 }, 	// (
  { 3, 33, 30, 0, 0, 0, 0 }, 	// )
  { 6, 42, 28, 62, 28, 42, 0 }, // *
  { 6, 8, 8, 62, 8, 8, 0 },	// +
  { 3, 64, 32, 0, 0, 0, 0 }, 	// ,
  { 6, 8, 8, 8, 8, 8, 0 }, 	// -
  { 3, 32, 0, 0, 0, 0, 0 }, 	// .
  { 4, 48, 12, 3, 0, 0, 0 }, 	// /
  { 5, 30, 37, 35, 30, 0, 0 }, // 0
  { 5, 4, 34, 63, 32, 0, 0 }, 	// 1
  { 5, 34, 49, 41, 38, 0, 0 }, // 2
  { 5, 18, 33, 37, 26, 0, 0 }, // 3
  { 5, 8, 12, 10, 63, 0, 0 }, 	// 4
  { 5, 23, 37, 37, 25, 0, 0 }, // 5
  { 5, 30, 37, 37, 24, 0, 0 }, // 6
  { 5, 1, 57, 5, 3, 0, 0 }, 	// 7
  { 5, 26, 37, 37, 26, 0, 0 }, // 8
  { 5, 18, 37, 37, 30, 0, 0 }, // 9
  { 3, 54, 0, 0, 0, 0, 0 }, 	// :
  { 3, 96, 54, 0, 0, 0, 0 }, 	// ;
  { 4, 8, 20, 34, 0, 0, 0 }, 	// <
  { 5, 20, 20, 20, 20, 0, 0 },	// =
  { 4, 34, 20, 8, 0, 0, 0 }, 	// >
  { 6, 2, 1, 41, 5, 2, 0 }, 	// ?
  { 6, 30, 33, 45, 41, 6, 0 }, 	// @
  { 5, 62, 5, 5, 62, 0, 0 },	// A
  { 5, 63, 37, 37, 26, 0, 0 },	// B
  { 5, 30, 33, 33, 18, 0, 0 },	// C
  { 5, 63, 33, 33, 30, 0, 0 },	// D
  { 5, 63, 37, 37, 33, 0, 0 },	// E
  { 5, 63, 5, 5, 1, 0, 0 },	// F
  { 5, 30, 33, 41, 26, 0, 0 },	// G
  { 5, 63, 4, 4, 63, 0, 0 }, 	// H
  { 4, 33, 63, 33, 0, 0, 0 }, 	// I
  { 5, 33, 65, 65, 63, 0, 0 },	// J
  { 5, 63, 12, 18, 33, 0, 0 },	// K
  { 5, 63, 32, 32, 32, 0, 0 },	// L
  { 6, 63, 2, 4, 2, 63, 0 },	// M
  { 5, 63, 6, 24, 63, 0, 0 }, 	// N
  { 5, 30, 33, 33, 30, 0, 0 },	// O
  { 5, 63, 5, 5, 2, 0, 0 }, 	// P
  { 5, 30, 33, 17, 46, 0, 0 },	// Q
  { 5, 63, 13, 21, 34, 0, 0 }, 	// R
  { 5, 18, 37, 37, 24, 0, 0 },	// S
  { 4, 1, 63, 1, 0, 0, 0 }, 	// T
  { 5, 31, 32, 32, 31, 0, 0 },	// U
  { 6, 3, 12, 48, 12, 3, 0 }, 	// V
  { 6, 31, 32, 16, 32, 31, 0 }, // W
  { 6, 49, 10, 4, 10, 49, 0 },	// X
  { 6, 1, 2, 60, 2, 1, 0 }, 	// Y
  { 5, 49, 41, 37, 35, 0, 0 },	// Z
  { 3, 63, 33, 0, 0, 0, 0 },	// [
  { 6, 2, 4, 8, 16, 32, 0 },	// Backslash
  { 3, 33, 63, 0, 0, 0, 0 },	// ]
  { 4, 2, 1, 2, 0, 0, 0 },	// ^
  { 5, 64, 64, 64, 64, 0, 0 },	// _
  { 3, 1, 2, 0, 0, 0, 0 }, 	// ´
  { 5, 24, 36, 36, 56, 0, 0 },	// a
  { 5, 63, 36, 36, 24, 0, 0 },	// b
  { 4, 24, 36, 36, 0, 0, 0 },	// c
  { 5, 24, 36, 36, 63, 0, 0 },	// d
  { 5, 24, 44, 44, 40, 0, 0 },	// e
  { 4, 16, 126, 17, 0, 0, 0 },	// f
  { 5, 8, 84, 84, 40, 0, 0 },	// g
  { 5, 63, 4, 4, 56, 0, 0 }, 	// h
  { 3, 29, 32, 0, 0, 0, 0 }, 	// i
  { 4, 64, 64, 61, 0, 0, 0 },	// j
  { 5, 63, 8, 20, 34, 0, 0 },	// k
  { 3, 31, 32, 0, 0, 0, 0 }, 	// l
  { 6, 60, 4, 60, 4, 56, 0 },	// m
  { 5, 60, 4, 4, 56, 0, 0 }, 	// n
  { 5, 24, 36, 36, 24, 0, 0 }, 	// o
  { 5, 124, 36, 36, 24, 0, 0 }, // p
  { 5, 24, 36, 36, 124, 0, 0 }, // q
  { 4, 60, 4, 8, 0, 0, 0 }, 	// r
  { 5, 40, 44, 44, 20, 0, 0 }, 	// s
  { 4, 4, 30, 36, 0, 0, 0 }, 	// t
  { 5, 28, 32, 32, 60, 0, 0 }, 	// u
  { 5, 12, 48, 48, 12, 0, 0 }, 	// v
  { 6, 28, 32, 28, 32, 28, 0 }, // w
  { 5, 36, 24, 24, 36, 0, 0 },	// x
  { 5, 12, 80, 80, 60, 0, 0 }, 	// y
  { 5, 36, 52, 44, 36, 0, 0 }, 	// z
  { 4, 4, 30, 33, 0, 0, 0 },	// {
  { 4, 0, 63, 0, 0, 0, 0 },	// |
  { 4, 33, 30, 4, 0, 0, 0 },	// }
  { 5, 2, 1, 2, 1, 0, 0 },	// ~
  { 6, 85, 170, 85, 170, 85, 170 }	// 127
};


void setColor(int color)
{
  internalColor = color;
}


/* 
 * our current LCDAdapter just acts like a parallel port.
 * To generate the required falling-edge on the E (clk) pin,
 * we write the actual command argument twice, first with E
 * asserted and right again with E deasserted.
 */
inline void command(int value)
{
  int *adr;
  
  adr = (int*) BASEADDR;

  *adr = value |  ENAMASK;
  *adr = value & ~ENAMASK;
  *adr = value |  ENAMASK;

}


void enableDisplay(int on)
{
  command(DISPLAYON | on);
}


void clearDisplay()
{
  int x=0;
  int y=0;
  int *adr;
  
  command( SETBYTEADR );
  for (y=0; y<8; y++) {
    command( SETPAGEADR | y );
    for (x=0; x<64; x++) {
      command( WRITE );
    }
  }
}


/** draw the least significant byte of 'value' at the given position */
void drawByte( int x, int y, int value ) {
  // int page = y >> 3;
  int chip = (x >= 64) ? CHIP2 : CHIP1;
  command(SETPAGEADR | y); // page
  command(SETBYTEADR | x);
  command(WRITE | chip | (value&0xff) );
}


void setPixel(int x, int y)
{
  int page = y >> 3;
  int bit = y & 7;
  int writeval = 1 << bit;

  int chip = (x >= 64) ? CHIP2 : CHIP1;
  
  command(SETPAGEADR | page);
  command(SETBYTEADR | x);
  command(WRITE | chip | writeval);
}


void horizLine(int x, int y, int length)
{
  int page = y >> 3;
  int bit = y & 7;
  int writeval = 1 << bit;
  int i=0;
  
  command(SETPAGEADR | page);
  command(SETBYTEADR | x);
  for (i=0; i<length; i++) {
    command(WRITE | CHIP1 | writeval);
  }
}


void vertLine(int x, int y, int length)
{
  int startPage = y >> 3;
  int startBit = y & 7;
  int endPage = (y+length) >> 3;
  int endBit = (y+length) & 7;
  int startval = 0;
  int writeval = 0xff;
  int endval = 0;
  int i=0;
  
  if (startPage == endPage) {
    writeval = (1 << endBit) - (1 << startBit);
    command(SETBYTEADR | x);
    command(SETPAGEADR | startPage);
    command(WRITE | CHIP1 | writeval);
  } else {
    startval = 0x100 - (1 << startBit);
    endval = (1 << endBit) - 1;
    command(SETBYTEADR | x);
    command(SETPAGEADR | startPage);
    command(WRITE | CHIP1 | startval);
    for (i=startPage+1; i<endPage; i++) {
      command(SETBYTEADR | x);
      command(SETPAGEADR | i);
      command(WRITE | CHIP1 | 0xff);
    }
    command(SETBYTEADR | x);
    command(SETPAGEADR | endPage);
    command(WRITE | CHIP1 | endval);
  }
}    
    
  
void setTextPos(int x, int y)
{
  x = x*5;
  if (x >= 64) {
    chipselect = CHIP2;
    x = x & 63;
  } else {
    chipselect = CHIP1;
  }
  ypos = y;
  xpos = x;
}


void text(char *string)
{
  int j;
  int value;
  int len;
  char ch;
  
  
  command(SETBYTEADR | xpos);
  command(SETPAGEADR | ypos);

  while (*string) {
    ch = *string & 127;
    len = charset[ch][0];
    if ((ch == 10) || ((xpos+len >= 64) && (chipselect == CHIP2))) {
      if (ch != 10) {
        string--;
      }
      len = 64-xpos;
      for (j=0; j<len; j++) {
        command( WRITE | chipselect );
      }
      xpos = 0;
      command( SETBYTEADR );
      if (chipselect == CHIP1) {
        for (j=0; j<64; j++) {
          command( WRITE | CHIP2 );
        }
      }
      ypos = (ypos + 1) & 7;
      command( SETPAGEADR | ypos );
      chipselect = CHIP1;
    } else {
      for (j=1; j<=len; j++) {
        command( WRITE | chipselect | charset[ch][j] );
        xpos++;
        if (xpos > 63) {
          xpos = 0;
          command( SETBYTEADR );
          chipselect = CHIP2;
        } 
      }
    }
    string++;
  }
}  


void bigtext(char *string)
{
  int j;
  int value;
  int len;
  char ch;
  int *adr;
  
  adr = (int*) BASEADDR;
  
  command(SETBYTEADR | xpos);
  command(SETPAGEADR | ypos);

  while (*string) {
    ch = *string & 127;
    len = charset[ch][0];
    if ((ch == 10) || ((xpos+(len*2) >= 64) && (chipselect == CHIP2))) {
      if (ch != 10) {
        string--;
      }
      len = 64-xpos;
      for (j=0; j<len; j++) {
        *adr = WRITE | chipselect;
      }
      xpos = 0;
      *adr = SETBYTEADR;
      if (chipselect == CHIP1) {
        for (j=0; j<64; j++) {
          *adr = WRITE | CHIP2;
        }
      }
      ypos = (ypos + 1) & 7;
      *adr = SETPAGEADR | ypos;
      chipselect = CHIP1;
    } else {
      for (j=1; j<=len; j++) {
        *adr = WRITE | chipselect | charset[ch][j];
        xpos++;
        if (xpos > 63) {
          xpos = 0;
          *adr = SETBYTEADR;
          chipselect = CHIP2;
        } 
        *adr = WRITE | chipselect | charset[ch][j];
        xpos++;
        if (xpos > 63) {
          xpos = 0;
          *adr = SETBYTEADR;
          chipselect = CHIP2;
        } 
      }
    }
    string++;
  }
}