/* --------------------------------------------------  Functions for setting 320x240 Arcade Monitor mode --------------------------------------------------*/#include "arcmon.h"/* indices into our register array */#define	CLOCK_INDEX				0#define	H_TOTAL_INDEX			1#define	H_DISPLAY_INDEX			2#define	H_BLANKING_START_INDEX	3#define	H_BLANKING_END_INDEX	4#define	H_RETRACE_START_INDEX	5#define	H_RETRACE_END_INDEX		6#define	V_TOTAL_INDEX			7#define	OVERFLOW_INDEX			8#define	MAXIMUM_SCANLINE_INDEX	10#define	V_RETRACE_START_INDEX	11#define	V_RETRACE_END_INDEX		12#define	V_END_INDEX				13#define	MEM_OFFSET_INDEX		14#define	V_BLANKING_START_INDEX	16#define	V_BLANKING_END_INDEX	17//functions//set the horizontal and vertical timingsvoid setarcadetimings(void);//center the arcade monitor modevoid centerarcademode(void);//asm function to set arcade monitor mode (in arcmode.s)void setarcademode(void);//timing valuesunsigned char arcade_h_timing = 105;  // horizontal timing, range 0-255, default 105unsigned char arcade_v_timing = 9;    // vertical timing,   range 0-255, default 9//center valuesunsigned char center_x = 8;           // center x, range 0 to 16, default 8unsigned char center_y = 4;           // center y, range 0 to 8,  default 4//array of register values to set arcade modeunsigned char vgaregs320x240[]={   0xe7,0x69,0x4f,0x4f,0x91,0x55,0x1f,0x09,0x11,0x00,0x40,0xf2,0xa4,0xef,0x28,0x00,0xf0,0xf2,0xe3,   0x09,   0x06,0x40,0x05,0x41,0x00};void arcade_monitor_mode(int h, int v, int x, int y){#if !defined( RAINE_WIN32 )   arcade_h_timing = h;   arcade_v_timing = v;   center_x = x;   center_y = y;//update array with 'tweak' horizontal and vertical counts	setarcadetimings();//update array with centering values	centerarcademode();//then set the registers	setarcademode();#endif}void setarcadetimings(void){//just copy the values in#if !defined( RAINE_WIN32 )	vgaregs320x240[H_TOTAL_INDEX] = arcade_h_timing;	vgaregs320x240[V_TOTAL_INDEX] = arcade_v_timing;#endif}void centerarcademode(void){#if !defined( RAINE_WIN32 )	int hrt, vrt_start, temp, vert_total, vert_display, center, hrt_start;	int vblnk_start,vrt,vblnk,actx,acty;	int hblnk = 3;//get +/- versions of the center vars	actx =(int)center_x - 8;	acty =(int)center_y - 4;//horizontal retrace width	hrt = 11;/* our center 'tweak' variable */	center = actx;/* set the hz retrace */	hrt_start = vgaregs320x240[H_RETRACE_START_INDEX];	hrt_start += center;/* make sure it's legal */	if (hrt_start <= vgaregs320x240[H_DISPLAY_INDEX])		hrt_start = vgaregs320x240[H_DISPLAY_INDEX] + 1;	vgaregs320x240[H_RETRACE_START_INDEX] = hrt_start;	temp = hrt_start + hrt;	vgaregs320x240[H_RETRACE_END_INDEX] = temp&0x1f; /* set the hz blanking */	temp = vgaregs320x240[H_DISPLAY_INDEX];   	vgaregs320x240[H_BLANKING_START_INDEX] = temp;   	temp += hblnk;   	vgaregs320x240[H_BLANKING_END_INDEX] = (temp&0x1f) | 0x80;/* get the vt retrace */	vrt_start = vgaregs320x240[V_RETRACE_START_INDEX] | ((vgaregs320x240[OVERFLOW_INDEX] & 0x04) << 6) |				((vgaregs320x240[OVERFLOW_INDEX] & 0x80) << 2);/* get the width of it */	temp = vrt_start & ~0x0f;	temp |=	(vgaregs320x240[V_RETRACE_END_INDEX] & 0x0f);	vrt = temp - vrt_start;/* set the new retrace start */	vrt_start += acty;/* check it's legal, get the display line count */	vert_display = (vgaregs320x240[V_END_INDEX] | ((vgaregs320x240[OVERFLOW_INDEX] & 0x02) << 7) |				((vgaregs320x240[OVERFLOW_INDEX] & 0x40) << 3)) + 1; 	if (vrt_start < vert_display)		vrt_start = vert_display;/* and get the vertical line count */	vert_total = vgaregs320x240[V_TOTAL_INDEX] | ((vgaregs320x240[OVERFLOW_INDEX] & 0x01) << 8) |				((vgaregs320x240[OVERFLOW_INDEX] & 0x20) << 4);	vgaregs320x240[V_RETRACE_START_INDEX] = (vrt_start & 0xff);	vgaregs320x240[OVERFLOW_INDEX] &= ~0x84;	vgaregs320x240[OVERFLOW_INDEX] |= ((vrt_start & 0x100) >> 6);	vgaregs320x240[OVERFLOW_INDEX] |= ((vrt_start & 0x200) >> 2);	temp = vrt_start + vrt;	if (temp > vert_total)		temp = vert_total;	vgaregs320x240[V_RETRACE_END_INDEX] &= ~0x0f;	vgaregs320x240[V_RETRACE_END_INDEX] |= (temp & 0x0f);/* get the start of vt blanking */	vblnk_start = vgaregs320x240[V_BLANKING_START_INDEX] | ((vgaregs320x240[OVERFLOW_INDEX] & 0x08) << 5) |					((vgaregs320x240[MAXIMUM_SCANLINE_INDEX] & 0x20) << 4);/* and the end */	temp = vblnk_start & ~0xff;	temp |= vgaregs320x240[V_BLANKING_END_INDEX];/* get the width */	vblnk = temp - vblnk_start;/* get the new value */	vblnk_start += acty;/* check it's legal */	if (vblnk_start < vert_display)		vblnk_start = vert_display;	if (vblnk_start > vert_total)		vblnk_start = vert_total;/* set vblank start */	vgaregs320x240[V_BLANKING_START_INDEX] = (vblnk_start & 0xff);	vgaregs320x240[OVERFLOW_INDEX] &= ~0x08;	vgaregs320x240[OVERFLOW_INDEX] |= ((vblnk_start & 0x100) >> 5);	vgaregs320x240[MAXIMUM_SCANLINE_INDEX] &= ~0x20;	vgaregs320x240[MAXIMUM_SCANLINE_INDEX] |= ((vblnk_start &0x200) >> 4);/* set the vblank end */	temp = vblnk_start + vblnk;/* check it's legal */	if (temp > vert_total)		temp = vert_total;	vgaregs320x240[V_BLANKING_END_INDEX] = (temp & 0xff);#endif}