/* Graphics support routines for this tutorial */

extern unsigned char *abuf;   		/* A000 buffer */
extern int tx, ty, bx, by;   	/* Clipping variables, top and bottom */
extern unsigned char currentcolor;

extern void setvideomode (int mode);
extern void setclipping (int x1, int y1, int x2, int y2);
extern void drawcolor (unsigned char col);
extern void setvga256 (void);
extern void horizontal_line (int x1, int x2, int y);