extern unsigned char ram[128*1024];
extern unsigned char a,y,x;

int grsim_input(void);
int grsim_update(void);
int grsim_init(void);
int color_equals(int new_color);
int basic_plot(unsigned char xcoord, unsigned char ycoord);
int basic_hlin(int x1, int x2, int at);
int basic_vlin(int y1, int y2, int at);
int gr(void);
int bload(char *filename, int address);
int scrn(unsigned char xcoord, unsigned char ycoord);
int grsim_unrle(unsigned char *rle_data, int address);
int home(void);
int grsim_put_sprite(int page,unsigned char *sprite_data, int xpos, int ypos);
int gr_copy(short source, short dest);
int text(void);
void basic_htab(int x);
void basic_vtab(int y);
void basic_print(char *string);
void basic_inverse(void);
void basic_normal(void);
int hlin(int page, int x1, int x2, int at);
int hlin_continue(int width);
int hlin_double_continue(int width);
int hlin_double(int page, int x1, int x2, int at);

int collision(int xx, int yy, int ground_color);

#define APPLE_UP        11
#define APPLE_DOWN      10
#define APPLE_LEFT      8
#define APPLE_RIGHT     21

#define COLOR_BLACK	0
#define COLOR_RED	1
#define COLOR_DARKBLUE	2
#define COLOR_PURPLE	3
#define COLOR_DARKGREEN	4
#define COLOR_GREY	5
#define COLOR_MEDIUMBLUE	6
#define COLOR_LIGHTBLUE	7
#define COLOR_BROWN	8
#define COLOR_ORANGE	9
#define COLOR_GREY2	10
#define COLOR_PINK	11
#define COLOR_LIGHTGREEN	12
#define COLOR_YELLOW	13
#define COLOR_AQUA	14
#define COLOR_WHITE	15