//video gen and sound
//D.5 is sync:1000 ohm + diode to 75 ohm resistor
//D.6 is video:330 ohm + diode to 75 ohm resistor  
//C.0 is sound

#pragma regalloc-    //I allocate the registers myself
#pragma optsize-     //optimize for speed
                    
#include <Mega32.h>   
#include <stdio.h>
#include <stdlib.h> 
#include <math.h> 
#include <delay.h>   

//cycles = 63.625 * 16 Note NTSC is 63.55 
//but this line duration makes each frame exactly 1/60 sec
//which is nice for keeping a realtime clock 
#define lineTime 1018
 
#define begin {
#define end   }
#define ScreenTop 30
#define ScreenBot 230
#define T0reload 256-60
#define MaxBlocks 14
#define width 126

//NOTE that v1 to v8 and i must be in registers!  
register char v1 @4; 
register char v2 @5;
register char v3 @6;
register char v4 @7;
register char v5 @8;
register char v6 @9;
register char v7 @10;
register char v8 @11; 
register int i @12;

#pragma regalloc+ 

char syncON, syncOFF; 
int LineCount, score;
unsigned int frame_count;
int time; 

//animation
char s;
int dx, dy;
unsigned int calcx, calcy;
char screenx, screeny;
unsigned int speed;
char out1[20], out2[20];
char level,bricks_remaining;
unsigned char paddle_position;
unsigned char platform_width;
unsigned char old_paddle_position;
unsigned char lives,brick_value,miss_penalty;
char startover,game_start;

char screen[1600]; //, t, ts[10]; 
char level_str[4]; 
char ball_str[4];
char bricks_str[5];
char end_game_str[18];
void calc_speed(void);
void setup_level(void);
void clear_screen(void);

char boot_str1[] = "ARKANOID";
char boot_str2[] = "BY";
char boot_str3[] = "RICHARD";
char boot_str4[] = "BALLANTYNE";
char boot_str5[] = "AND";
char boot_str6[] = "DAVID";
char boot_str7[] = "FRANKFORD";
			
//Point plot lookup table
flash char pos[8]={0x80,0x40,0x20,0x10,0x08,0x04,0x02,0x01};			

//define some character bitmaps
//5x7 characters
flash char bitmap[38][7]={ 
	//0
	0b01110000,
	0b10001000,
	0b10011000,
	0b10101000,
	0b11001000,
	0b10001000,
	0b01110000,
	//1
	0b00100000,
	0b01100000,
	0b00100000,
	0b00100000,
	0b00100000,
	0b00100000,
	0b01110000,  
	//2
	0b01110000,
	0b10001000,
	0b00001000,
	0b00010000,
	0b00100000,
	0b01000000,
	0b11111000,
    //3
	0b11111000,
	0b00010000,
	0b00100000,
	0b00010000,
	0b00001000,
	0b10001000,
	0b01110000,
	//4
	0b00010000,
	0b00110000,
	0b01010000,
	0b10010000,
	0b11111000,
	0b00010000,
	0b00010000,
	//5
	0b11111000,
	0b10000000,
	0b11110000,
	0b00001000,
	0b00001000,
	0b10001000,
	0b01110000,
	//6
	0b01000000,
	0b10000000,
	0b10000000,
	0b11110000,
	0b10001000,
	0b10001000,
	0b01110000,
	//7
	0b11111000,
	0b00001000,
	0b00010000,
	0b00100000,
	0b01000000,
	0b10000000,
	0b10000000,
	//8
	0b01110000,
	0b10001000,
	0b10001000,
	0b01110000,
	0b10001000,
	0b10001000,
	0b01110000,
	//9
	0b01110000,
	0b10001000,
	0b10001000,
	0b01111000,
	0b00001000,
	0b00001000,
	0b00010000,  
	//A
	0b01110000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b11111000,
	0b10001000,
	0b10001000,
	//B
	0b11110000,
	0b10001000,
	0b10001000,
	0b11110000,
	0b10001000,
	0b10001000,
	0b11110000,
	//C
	0b01110000,
	0b10001000,
	0b10000000,
	0b10000000,
	0b10000000,
	0b10001000,
	0b01110000,
	//D
	0b11110000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b11110000,
	//E
	0b11111000,
	0b10000000,
	0b10000000,
	0b11111000,
	0b10000000,
	0b10000000,
	0b11111000,
	//F
	0b11111000,
	0b10000000,
	0b10000000,
	0b11111000,
	0b10000000,
	0b10000000,
	0b10000000,
	//G
	0b01110000,
	0b10001000,
	0b10000000,
	0b10011000,
	0b10001000,
	0b10001000,
	0b01110000,
	//H
	0b10001000,
	0b10001000,
	0b10001000,
	0b11111000,
	0b10001000,
	0b10001000,
	0b10001000,
	//I
	0b01110000,
	0b00100000,
	0b00100000,
	0b00100000,
	0b00100000,
	0b00100000,
	0b01110000,
	//J
	0b00111000,
	0b00010000,
	0b00010000,
	0b00010000,
	0b00010000,
	0b10010000,
	0b01100000,
	//K
	0b10001000,
	0b10010000,
	0b10100000,
	0b11000000,
	0b10100000,
	0b10010000,
	0b10001000,
	//L
	0b10000000,
	0b10000000,
	0b10000000,
	0b10000000,
	0b10000000,
	0b10000000,
	0b11111000,
	//M
	0b10001000,
	0b11011000,
	0b10101000,
	0b10101000,
	0b10001000,
	0b10001000,
	0b10001000,
	//N
	0b10001000,
	0b10001000,
	0b11001000,
	0b10101000,
	0b10011000,
	0b10001000,
	0b10001000,
	//O
	0b01110000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b01110000,
	//P
	0b11110000,
	0b10001000,
	0b10001000,
	0b11110000,
	0b10000000,
	0b10000000,
	0b10000000,
	//Q
	0b01110000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b10101000,
	0b10010000,
	0b01101000,
	//R
	0b11110000,
	0b10001000,
	0b10001000,
	0b11110000,
	0b10100000,
	0b10010000,
	0b10001000,
	//S
	0b01111000,
	0b10000000,
	0b10000000,
	0b01110000,
	0b00001000,
	0b00001000,
	0b11110000,
	//T
	0b11111000,
	0b00100000,
	0b00100000,
	0b00100000,
	0b00100000,
	0b00100000,
	0b00100000,
	//U
	0b10001000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b01110000,
	//V
	0b10001000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b01010000,
	0b00100000,
	//W
	0b10001000,
	0b10001000,
	0b10001000,
	0b10101000,
	0b10101000,
	0b10101000,
	0b01010000,
	//X
	0b10001000,
	0b10001000,
	0b01010000,
	0b00100000,
	0b01010000,
	0b10001000,
	0b10001000,
	//Y
	0b10001000,
	0b10001000,
	0b10001000,
	0b01010000,
	0b00100000,
	0b00100000,
	0b00100000,
	//Z
	0b11111000,
	0b00001000,
	0b00010000,
	0b00100000,
	0b01000000,
	0b10000000,
	0b11111000,
	//figure1
	0b00000000,
	0b00000000,
	0b00000000,
	0b00000000,
	0b00000000,
	0b00000000,
	0b00000000,
	//figure2
	0b00000000,
	0b00000000,
	0b00000000,
	0b00000000,
	0b00000000,
	0b00000000,
	0b00000000};


//================================ 
//3x5 font numbers, then letters
//packed two per definition for fast 
//copy to the screen at x-position divisible by 4
flash char smallbitmap[39][5]={ 
	//0
    0b11101110,
	0b10101010,
	0b10101010,
	0b10101010,
	0b11101110,
	//1
	0b01000100,
	0b11001100,
	0b01000100,
	0b01000100,
	0b11101110,
	//2
	0b11101110,
	0b00100010,
	0b11101110,
	0b10001000,
	0b11101110,
	//3
	0b11101110,
	0b00100010,
	0b11101110,
	0b00100010,
	0b11101110,
	//4
	0b10101010,
	0b10101010,
	0b11101110,
	0b00100010,
	0b00100010,
	//5
	0b11101110,
	0b10001000,
	0b11101110,
	0b00100010,
	0b11101110,
	//6
	0b11001100,
	0b10001000,
	0b11101110,
	0b10101010,
	0b11101110,
	//7
	0b11101110,
	0b00100010,
	0b01000100,
	0b10001000,
	0b10001000,
	//8
	0b11101110,
	0b10101010,
	0b11101110,
	0b10101010,
	0b11101110,
	//9
	0b11101110,
	0b10101010,
	0b11101110,
	0b00100010,
	0b01100110,
	//:
	0b00000000,
	0b01000100,
	0b00000000,
	0b01000100,
	0b00000000,
	//=
	0b00000000,
	0b11101110,
	0b00000000,
	0b11101110,
	0b00000000,
	//blank
	0b00000000,
	0b00000000,
	0b00000000,
	0b00000000,
	0b00000000,
	//A
	0b11101110,
	0b10101010,
	0b11101110,
	0b10101010,
	0b10101010,
	//B
	0b11001100,
	0b10101010,
	0b11101110,
	0b10101010,
	0b11001100,
	//C
	0b11101110,
	0b10001000,
	0b10001000,
	0b10001000,
	0b11101110,
	//D
	0b11001100,
	0b10101010,
	0b10101010,
	0b10101010,
	0b11001100,
	//E
	0b11101110,
	0b10001000,
	0b11101110,
	0b10001000,
	0b11101110,
	//F
	0b11101110,
	0b10001000,
	0b11101110,
	0b10001000,
	0b10001000,
	//G
	0b11101110,
	0b10001000,
	0b10001000,
	0b10101010,
	0b11101110,
	//H
	0b10101010,
	0b10101010,
	0b11101110,
	0b10101010,
	0b10101010,
	//I
	0b11101110,
	0b01000100,
	0b01000100,
	0b01000100,
	0b11101110,
	//J
	0b00100010,
	0b00100010,
	0b00100010,
	0b10101010,
	0b11101110,
	//K
	0b10001000,
	0b10101010,
	0b11001100,
	0b11001100,
	0b10101010,
	//L
	0b10001000,
	0b10001000,
	0b10001000,
	0b10001000,
	0b11101110,
	//M
	0b10101010,
	0b11101110,
	0b11101110,
	0b10101010,
	0b10101010,
	//N
	0b00000000,
	0b11001100,
	0b10101010,
	0b10101010,
	0b10101010,
	//O
	0b01000100,
	0b10101010,
	0b10101010,
	0b10101010,
	0b01000100,
	//P
	0b11101110,
	0b10101010,
	0b11101110,
	0b10001000,
	0b10001000,
	//Q
	0b01000100,
	0b10101010,
	0b10101010,
	0b11101110,
	0b01100110,
	//R
	0b11101110,
	0b10101010,
	0b11001100,
	0b11101110,
	0b10101010,
	//S
	0b11101110,
	0b10001000,
	0b11101110,
	0b00100010,
	0b11101110,
	//T
	0b11101110,
	0b01000100,
	0b01000100,
	0b01000100,
	0b01000100, 
	//U
	0b10101010,
	0b10101010,
	0b10101010,
	0b10101010,
	0b11101110, 
	//V
	0b10101010,
	0b10101010,
	0b10101010,
	0b10101010,
	0b01000100,
	//W
	0b10101010,
	0b10101010,
	0b11101110,
	0b11101110,
	0b10101010,
	//X
	0b00000000,
	0b10101010,
	0b01000100,
	0b01000100,
	0b10101010,
	//Y
	0b10101010,
	0b10101010,
	0b01000100,
	0b01000100,
	0b01000100,
	//Z
	0b11101110,
	0b00100010,
	0b01000100,
	0b10001000,
	0b11101110
	};
	
flash char level1[14][2] = {
	 {8, 38}, {16, 38}, {24, 38}, {32, 38}, {40, 38}, {48, 38}, {56, 38}, {64, 38},
	 {72, 38}, {80, 38}, {88, 38}, {96, 38}, {104, 38}, {112, 38}
};

flash char level2[28][2] = {
	 {8, 38}, {16, 38}, {24, 38}, {32, 38}, {40, 38}, {48, 38}, {56, 38}, {64, 38},
	 {72, 38}, {80, 38}, {88, 38}, {96, 38}, {104, 38}, {112, 38},
	 {8, 34}, {16, 34}, {24, 34}, {32, 34}, {40, 34}, {48, 34}, {56, 34}, {64, 34},
	 {72, 34}, {80, 34}, {88, 34}, {96, 34}, {104, 34}, {112, 34}
};

flash char level3[42][2] = {
	 {8, 38}, {16, 38}, {24, 38}, {32, 38}, {40, 38}, {48, 38}, {56, 38}, {64, 38},
	 {72, 38}, {80, 38}, {88, 38}, {96, 38}, {104, 38}, {112, 38},
	 {8, 34}, {16, 34}, {24, 34}, {32, 34}, {40, 34}, {48, 34}, {56, 34}, {64, 34},
	 {72, 34}, {80, 34}, {88, 34}, {96, 34}, {104, 34}, {112, 34},
	 {8, 30}, {16, 30}, {24, 30}, {32, 30}, {40, 30}, {48, 30}, {56, 30}, {64, 30},
	 {72, 30}, {80, 30}, {88, 30}, {96, 30}, {104, 30}, {112, 30}
};

flash char level4[56][2] = {
	 {8, 38}, {16, 38}, {24, 38}, {32, 38}, {40, 38}, {48, 38}, {56, 38}, {64, 38},
	 {72, 38}, {80, 38}, {88, 38}, {96, 38}, {104, 38}, {112, 38},
	 {8, 34}, {16, 34}, {24, 34}, {32, 34}, {40, 34}, {48, 34}, {56, 34}, {64, 34},
	 {72, 34}, {80, 34}, {88, 34}, {96, 34}, {104, 34}, {112, 34},
	 {8, 30}, {16, 30}, {24, 30}, {32, 30}, {40, 30}, {48, 30}, {56, 30}, {64, 30},
	 {72, 30}, {80, 30}, {88, 30}, {96, 30}, {104, 30}, {112, 30},
	 {8, 26}, {16, 26}, {24, 26}, {32, 26}, {40, 26}, {48, 26}, {56, 26}, {64, 26},
	 {72, 26}, {80, 26}, {88, 26}, {96, 26}, {104, 26}, {112, 26}
};

flash char level5[70][2] = {
	 {8, 38}, {16, 38}, {24, 38}, {32, 38}, {40, 38}, {48, 38}, {56, 38}, {64, 38},
	 {72, 38}, {80, 38}, {88, 38}, {96, 38}, {104, 38}, {112, 38},
	 {8, 34}, {16, 34}, {24, 34}, {32, 34}, {40, 34}, {48, 34}, {56, 34}, {64, 34},
	 {72, 34}, {80, 34}, {88, 34}, {96, 34}, {104, 34}, {112, 34},
	 {8, 30}, {16, 30}, {24, 30}, {32, 30}, {40, 30}, {48, 30}, {56, 30}, {64, 30},
	 {72, 30}, {80, 30}, {88, 30}, {96, 30}, {104, 30}, {112, 30},
	 {8, 26}, {16, 26}, {24, 26}, {32, 26}, {40, 26}, {48, 26}, {56, 26}, {64, 26},
	 {72, 26}, {80, 26}, {88, 26}, {96, 26}, {104, 26}, {112, 26},
	 {8, 22}, {16, 22}, {24, 22}, {32, 22}, {40, 22}, {48, 22}, {56, 22}, {64, 22},
	 {72, 22}, {80, 22}, {88, 22}, {96, 22}, {104, 22}, {112, 22}
};

//==================================
//This is the sync generator and raster generator. It MUST be entered from 
//sleep mode to get accurate timing of the sync pulses
#pragma warn-
interrupt [TIM1_COMPA] void t1_cmpA(void)  
begin 
  //start the Horizontal sync pulse    
  PORTD = syncON;     
  //count timer 0 at 1/usec
  TCNT0=0;
  //update the curent scanline number
  LineCount ++ ;   
  
  ADCSR = 0xC6; //read value off AD converter
 
  //begin inverted (Vertical) synch after line 247
  if (LineCount==248)
  begin 
    syncON = 0b00100000;
    syncOFF = 0;
  end
  //back to regular sync after line 250
  if (LineCount==251)	
  begin
    syncON = 0;
    syncOFF = 0b00100000;
  end  
  //start new frame after line 262
  if (LineCount==263) 
  begin
     LineCount = 1;
  end  
  
  delay_us(2); //adjust to make 5 us pulses
  //end sync pulse
  PORTD = syncOFF;   
  
  if (LineCount<ScreenBot && LineCount>=ScreenTop) 
    { 
       //compute byte index for beginning of the next line
       //left-shift 4 would be individual lines
       // <<3 means line-double the pixels 
       //The 0xfff8 truncates the odd line bit
       //i=(LineCount-ScreenTop)<<3 & 0xfff8; //
       
       #asm
       push r16
       lds   r12, _LineCount
       lds   r13, _Linecount+1
       ldi   r16, 30
       sub  r12, r16 
       ldi  r16,0
       sbc  r13, r16 
       lsl  r12
       rol  r13
       lsl  r12
       rol  r13
       lsl  r12    
       rol  r13
       mov  r16,r12
       andi r16,0xf0
       mov  r12,r16
       pop r16 
       #endasm
        
       //load 16 registers with screen info
       #asm
       push r14
       push r15
       push r16
       push r17
       push r18 
       push r19 
       push r26
       push r27
       
       ldi  r26,low(_screen)   ;base address of screen
       ldi  r27,high(_screen)   
       add  r26,r12            ;offset into screen (add i)
       adc  r27,r13
       ld   r4,x+   	       ;load 16 registers and inc pointer
       ld   r5,x+
       ld   r6,x+  
       ld   r7,x+
       ld   r8,x+ 
       ld   r9,x+
       ld   r10,x+  
       ld   r11,x+
       ld   r12,x+ 
       ld   r13,x+
       ld   r14,x+  
       ld   r15,x+
       ld   r16,x+   
       ld   r17,x+  
       ld   r18,x+
       ld   r19,x 
       
       pop  r27
       pop  r26
       #endasm  

       delay_us(4);  //adjust to center image on screen
       
       //blast 16 bytes to the screen   
       #asm
       ;but first a macro to make the code shorter  
       ;the macro takes a register number as a parameter
       ;and dumps its bits serially to portD.6   
       ;the nop can be eliminated to make the display narrower
       .macro videobits ;regnum
        BST  @0,7
	IN   R30,0x12
	BLD  R30,6
	nop
	OUT  0x12,R30  
	
	BST  @0,6
	IN   R30,0x12
	BLD  R30,6
	nop
	OUT  0x12,R30 
	
	BST  @0,5
	IN   R30,0x12
	BLD  R30,6 
	nop
	OUT  0x12,R30 
	
	BST  @0,4
	IN   R30,0x12
	BLD  R30,6
	nop
	OUT  0x12,R30 
	
	BST  @0,3
	IN   R30,0x12
	BLD  R30,6
	nop
	OUT  0x12,R30 
	
	BST  @0,2
	IN   R30,0x12
	BLD  R30,6
	nop
	OUT  0x12,R30 
	
	BST  @0,1
	IN   R30,0x12
	BLD  R30,6 
	nop
	OUT  0x12,R30 
	
	BST  @0,0
	IN   R30,0x12
	BLD  R30,6
	nop
	OUT  0x12,R30 
       .endm     
        
	videobits r4 ;video line -- byte 1
        videobits r5 ;byte 2  
        videobits r6 ;byte 3
        videobits r7 ;byte 4
        videobits r8 ;byte 5
        videobits r9 ;byte 6
        videobits r10 ;byte 7
        videobits r11 ;byte 8 
        videobits r12 ;byte 9
        videobits r13 ;byte 10  
        videobits r14 ;byte 11
        videobits r15 ;byte 12
        videobits r16 ;byte 13
        videobits r17 ;byte 14
        videobits r18 ;byte 15
        videobits r19 ;byte 16
	clt   ;clear video after the last pixel on the line
	IN   R30,0x12
	BLD  R30,6
	OUT  0x12,R30
								
       pop r19
       pop r18
       pop r17 
       pop r16  
       pop r15
       pop r14
       #endasm
              
    }
    
    if (!ADCSR.6) {
    		paddle_position = ADCH>>1;
		if (paddle_position < platform_width) {
			paddle_position = platform_width;
		}
		else if (paddle_position > width-(platform_width)) {
			paddle_position = width-(platform_width);
		}
    }
     
end  
#pragma warn+

//==================================
//plot one point 
//at x,y with color 1=white 0=black 2=invert 
#pragma warn-
void video_pt(char x, char y, char c)
begin   
	
	#asm
	;  i=(x>>3) + ((int)y<<4) ;   the byte with the pixel in it

	push r16
	ldd r30,y+2 		;get x
	lsr r30
	lsr r30
	lsr r30     		;divide x by 8
	ldd r12,y+1 		;get y
       	lsl r12     		;mult y by 16
       	clr r13
	lsl r12
	rol r13
	lsl r12
	rol r13
	lsl r12
	rol r13
	add r12, r30     	;add in x/8
	
	;v2 = screen[i];   r5
        ;v3 = pos[x & 7];  r6
	;v4 = c            r7
	ldi r30,low(_screen)
	ldi r31,high(_screen)
	add r30, r12
	adc r31, r13
	ld r5,Z  		;get screen byte
	ldd r26,y+2 		;get x
	ldi r27,0
	andi r26,0x07           ;form x & 7 
	ldi r30,low(_pos*2)  
	ldi r31,high(_pos*2)
	add r30,r26
	adc r31,r27
	lpm r6,Z
	ld r16,y 		;get c 
       
       ;if (v4==1) screen[i] = v2 | v3 ; 
       ;if (v4==0) screen[i] = v2 & ~v3; 
       ;if (v4==2) screen[i] = v2 ^ v3 ; 
       
       cpi r16,1
       brne tst0
       or  r5,r6
       tst0:
       cpi r16,0
       brne tst2 
       com r6
       and r5,r6
       tst2:
       cpi r16,2
       brne writescrn
       eor r5,r6
       writescrn:
       	ldi r30,low(_screen)
	ldi r31,high(_screen)
	add r30, r12
	adc r31, r13
	st Z, r5        	;write the byte back to the screen
	
	pop r16
	#endasm
       
end
#pragma warn+

//==================================
// put a big character on the screen
// c is index into bitmap
void video_putchar(char x, char y, char c)  
begin 
    v7 = x;
    for (v6=0;v6<7;v6++) 
    begin
        v1 = bitmap[c][v6]; 
        v8 = y+v6;
        video_pt(v7,   v8, (v1 & 0x80)==0x80);  
        video_pt(v7+1, v8, (v1 & 0x40)==0x40); 
        video_pt(v7+2, v8, (v1 & 0x20)==0x20);
        video_pt(v7+3, v8, (v1 & 0x10)==0x10);
        video_pt(v7+4, v8, (v1 & 0x08)==0x08);
    end
end

//==================================
// put a string of big characters on the screen
void video_puts(char x, char y, char *str)
begin
	char i ;
	for (i=0; str[i]!=0; i++)
	begin  
		if (str[i]>=0x30 && str[i]<=0x3a) 
			video_putchar(x,y,str[i]-0x30);
		else if (str[i]==' ') video_putchar(x, y, 37);
		else video_putchar(x,y,str[i]-0x40+9);
		x = x+6;	
	end
end
      
//==================================
// put a small character on the screen
// x-cood must be on divisible by 4 
// c is index into bitmap
void video_smallchar(char x, char y, char c)  
begin 
	char mask;
	i=((int)x>>3) + ((int)y<<4) ;
	if (x == (x & 0xf8)) mask = 0x0f;     //f8
	else mask = 0xf0;
	
	screen[i] =    (screen[i] & mask) | (smallbitmap[c][0] & ~mask); 
   	screen[i+16] = (screen[i+16] & mask) | (smallbitmap[c][1] & ~mask);
        screen[i+32] = (screen[i+32] & mask) | (smallbitmap[c][2] & ~mask);
        screen[i+48] = (screen[i+48] & mask) | (smallbitmap[c][3] & ~mask);
   	screen[i+64] = (screen[i+64] & mask) | (smallbitmap[c][4] & ~mask); 
end  

//==================================
// put a string of small characters on the screen
// x-cood must be on divisible by 4 
void video_putsmalls(char x, char y, char *str)
begin
	char i ;
	for (i=0; str[i]!=0; i++)
	begin  
		if (str[i]>=0x30 && str[i]<=0x3a) 
			video_smallchar(x,y,str[i]-0x30);
		else video_smallchar(x,y,str[i]-0x40+12);
		x = x+4;	
	end
end
       
//==================================
//plot a line 
//at x1,y1 to x2,y2 with color 1=white 0=black 2=invert 
//NOTE: this function requires signed chars   
//Code is from David Rodgers,
//"Procedural Elements of Computer Graphics",1985
void video_line(char x1, char y1, char x2, char y2, char c)
begin   
	int e;
	signed char dx,dy,j, temp;
	signed char s1,s2, xchange;
        signed char x,y;
        
	x = x1;
	y = y1;
	dx = cabs(x2-x1);
	dy = cabs(y2-y1);
	s1 = csign(x2-x1);
	s2 = csign(y2-y1);
	xchange = 0;   
	if (dy>dx)
	begin
		temp = dx;
		dx = dy;
		dy = temp;
		xchange = 1;
	end 
	e = ((int)dy<<1) - dx;   
	for (j=0; j<=dx; j++)
	begin
		video_pt(x,y,c) ; 
		if (e>=0)
		begin
			if (xchange==1) x = x + s1;
			else y = y + s2;
			e = e - ((int)dx<<1);
		end
		if (xchange==1) y = y + s2;
		else x = x + s1;
		e = e + ((int)dy<<1);
	end
end

//==================================
//return the value of one point 
//at x,y with color 1=white 0=black 2=invert
char video_set(char x, char y)
begin
	//The following construction 
  	//detects exactly one bit at the x,y location
	i=((int)x>>3) + ((int)y<<4) ;  
    return ( screen[i] & 1<<(7-(x & 0x7)));   	
end

void video_brick(char x, char y, char c)
begin   
	
	#asm
	;  i=(x>>3) + ((int)y<<4) ;   the byte with the pixel in it

	push r16
	ldd r30,y+2 		;get x
	lsr r30
	lsr r30
	lsr r30     		;divide x by 8
	ldd r12,y+1 		;get y
       	lsl r12     		;mult y by 16
       	clr r13
	lsl r12
	rol r13
	lsl r12
	rol r13
	lsl r12
	rol r13
	add r12, r30     	;add in x/8
	
	;v2 = screen[i];   r5
        ;v3 = pos[x & 7];  r6
	;v4 = c            r7
	ldi r30,low(_screen)
	ldi r31,high(_screen)
	add r30, r12
	adc r31, r13
	ld r5,Z  		;get screen byte
; now have the bytes current value in r5
	ld r16,y 		;get c 
       
       ;if (v4==1) screen[i] = v2 | v3 ; 
       ;if (v4==0) screen[i] = v2 & ~v3; 
       ;if (v4==2) screen[i] = v2 ^ v3 ; 
       
       clr r5
       cpi r16,1
       brne tst0a
       ldi r16, 0x7e
       or r5,r16
       
     tst0a:
  
 	ldi r30,low(_screen)
	ldi r31,high(_screen)
	add r30, r12
	adc r31, r13
	st Z, r5        	;write the byte back to the screen
	
	pop r16
	#endasm
       
end

void clear_screen (void) {
	int j;
	for (j = 0; j < 1600; j++)
		screen[j] = 0;
}

//==================================
// set up the ports and timers
void main(void)
begin

  //init timer 1 to generate sync
  OCR1A = lineTime; 	//One NTSC line
  TCCR1B = 9; 		//full speed; clear-on-match
  TCCR1A = 0x00;	//turn off pwm and oc lines
  TIMSK = 0x10;		//enable interrupt T1 cmp 
  
  //init ports
  DDRD = 0xf0;		//video out and switches
  //D.5 is sync:1000 ohm + diode to 75 ohm resistor
  //D.6 is video:330 ohm + diode to 75 ohm resistor

  ADMUX = 0x20;   //sets internal reference and analog channel 0 
  ADCSR = 0x80; //enables AD converter
//  ADMUX = 0b11100000;   
   //enable ADC and set prescaler to 1/64*8MHz=125,000
   //and set int enable
//  ADCSR = 0x80 + 0x06 + 0x08; 
  //init timer 0 to 1/uSec  

  TCCR0 = 2;
  //initialize synch constants 
  LineCount = 1;
  syncON = 0b00000000;
  syncOFF = 0b00100000;
  
  startover = 0;
  level = 0;
  game_start = 1;
  clear_screen();
  while (1) {
	  platform_width = 7;
	  //old_paddle_position = 128;  
	  //init animation
	  lives = 2;
	  frame_count=0;
	  bricks_remaining = 0;
	  //video_pt(screenx,screeny,1);
	  //enable sleep mode
	  MCUCR = 0b10000000;
	  #asm ("sei");
      //The following loop executes once/video line during lines
	  //1-230, then does all of the frame-end processing
	  while((!startover) && (!game_start))
	  {
	  	//stall here until next line starts
	    //sleep enable; mode=idle  
	    //use sleep to make entry into sync ISR uniform time  
		#asm ("sleep"); 
	    //The following code executes during the vertical blanking
	    //Code here can be as long as  
	    //a total of 60 lines x 63.5 uSec/line x 8 cycles/uSec 
    
	    if (LineCount==231)
	    { 
	         //the animated point
		   if (bricks_remaining ==0) {
		   	level++;
		   	lives++;
		   	bricks_remaining = MaxBlocks*level; //change maxblocks later to value dependant on current level
		   	setup_level();
		   }
           calc_speed();
    	   if (lives == 0) {
		   	startover = 1;
		    clear_screen();
		   }
    	}  //line 231
	  }  //while !startover
  	  while(startover || level==6 || game_start)
	  {
	   #asm ("sleep"); 
	    if (LineCount==231)
	    {
			if (startover && frame_count==0) {
			 	sprintf(end_game_str,"GAME OVER");
				video_puts(40, 47, end_game_str);
			}
			else if ((level==6) && (frame_count==0)) {
			 	sprintf(end_game_str,"YOU WIN");
				video_puts(40, 47, end_game_str);
			}
			else if ((frame_count==0) && (game_start)) {
				video_puts(42, 15, boot_str1);
				video_puts(59, 30, boot_str2);
			}
			else if ((frame_count==1) && (game_start)) {
				video_puts(10, 45, boot_str3);
			}
			else if ((frame_count==2) && (game_start)) {
				video_puts(55, 45, boot_str4);
			}
			else if ((frame_count==3) && (game_start)) {
				video_puts(57, 60, boot_str5);
			}
			else if ((frame_count==4) && (game_start)) {
				video_puts(20, 75, boot_str6);
			}
			else if ((frame_count==5) && (game_start)) {
				video_puts(55, 75, boot_str7);
			}

			frame_count++;
			if (frame_count > 200) { //wait for 7 seconds
				startover = 0;
				frame_count = 0;
				level = 0;
				game_start = 0;
				lives = 2;
				score = 0;
			}
	    }  //line 231
	  }  //while startover
	} // while(1)
}  //main

void calc_speed(void) {
//	char paddle_pos_str[4];  //test code - string is printed to screen
     video_pt(screenx,screeny,0) ; //erase old one
     calcx = calcx + dx;
     calcy = calcy + dy; 
     s = video_set(screenx,screeny);
     if (s>0) dy = -dy;    //if true, must be a line there
     screenx = calcx>>9;
     screeny = calcy>>9;
     sprintf(out1, "%4d %4d", dx, dy);

	video_line(old_paddle_position-platform_width,99,old_paddle_position+platform_width,99,0);
	video_line(paddle_position-platform_width,99,paddle_position+platform_width,99,1);
     old_paddle_position = paddle_position;

  	if (screenx>=124 || screenx<=1) dx = -dx;
     else if (screeny<=12) dy = -dy;
     
     // Determine whether platform is hit at screen bottom
	else if (screeny >= 98) {
		if ((screenx >= paddle_position-platform_width)&&
		(screenx <= paddle_position+platform_width)) {
			dx = -((int)((signed)paddle_position-(signed)screenx))<<3;
			if (score>= miss_penalty) {
				score-=miss_penalty;
			}
		}
		else {
			lives--;
			calcx = 32768;
			calcy = 50000;
			dx = 10;
		}
		dy = -(int)(sqrt(speed - dx^2));
		dx <<=3;
		dy <<=3;
	}
	
	// Determine whether an obstacle was hit
	else if (screen[(screenx>>3) + ((int)screeny<<4)]&pos[screenx&7]) {
		if (screen[(screenx>>3) + ((int)screeny+2<<4)]&pos[screenx&7] ||
			screen[(screenx>>3) + ((int)screeny-2<<4)]&pos[screenx&7])
			dx = -dx;
		else
			dy = -dy;
		//erase 2 brick layers (one brick..)
		video_brick(screenx, screeny&0xfe, 0);
		video_brick(screenx, screeny|0x01, 0);
		bricks_remaining--;
		score+=brick_value;			
	}
     video_pt(screenx,screeny,1) ;

	// Print status info	
 	sprintf(level_str,"L%d",level);
 	sprintf(bricks_str,"%2d",score);
 	sprintf(ball_str,"B%2d",lives);

	video_puts(3,2,level_str);
	video_puts(50,2,bricks_str);
	video_puts(100,2,ball_str);
//  	video_puts(10,50,out1);

//testing paddle position & ADC
//	   sprintf(paddle_pos_str,"%3u",paddle_position);
//       video_puts(50,50,paddle_pos_str);
//end paddle position testing   
}

void setup_level(void) {
	char i,j;
 #asm ("cli");
     clear_screen();   
	miss_penalty = 1*level;
	brick_value = 10*level;
	speed = 4000+1000*level;
    calcx=32768; 
	calcy=50000;
	dx=10;
	dy = -(int)(sqrt(speed - dx^2));
	dx<<=3;
	dy<<=3;
	video_line(0,0,0,99,1);
	video_line(width,0,width,99,1);
     //top line & bottom lines
	video_line(0,0,width,0,1);
	video_line(0,10,width,10,1);

	switch(level) {
		case 1:
			for (i = 0; i < 14; i++) {
				video_brick(level1[i][0], level1[i][1], 1);
				video_brick(level1[i][0], level1[i][1]+1, 1);
			}
			break;
		case 2:
			for (i = 0; i < 28; i++) {
				video_brick(level2[i][0], level2[i][1], 1);
				video_brick(level2[i][0], level2[i][1]+1, 1);
			}
			break;
		case 3:
			for (i = 0; i < 42; i++) {
				video_brick(level3[i][0], level3[i][1], 1);
				video_brick(level3[i][0], level3[i][1]+1, 1);
			}
			break;
		case 4:
			for (i = 0; i < 56; i++) {
				video_brick(level4[i][0], level4[i][1], 1);
				video_brick(level4[i][0], level4[i][1]+1, 1);
			}
			break;
		case 5:
			for (i = 0; i < 70; i++) {
				video_brick(level5[i][0], level5[i][1], 1);
				video_brick(level5[i][0], level5[i][1]+1, 1);
			}
			break;

	default:
		;
	}
 #asm ("sei");
}