#include "genesis.h"

#define MOUSE_PORT ((volatile u8*)0xA10003)
#define Z80_HALT  *((volatile u16*)0xA11100)

#define MOUSE_DELAY 32

static inline void delay(void) {
    __asm__ volatile (
        "move.w %0,%%d0\n\t"
        "1: subq.w #1,%%d0\n\t"
        "bne.s 1b"
        :
        : "i"(MOUSE_DELAY)
        : "d0"
    );
}

int main() {
    VDP_setTextPlane(0);
    VDP_drawText("Sega Mega Mouse RAW reader", 7, 27);
	VDP_drawText("RAW nibbles:", 14,0);
    u8 nibbles[16] = {0};
    s16 x = 0;
    s16 y = 0;

    char buf[40]; //буфер строки для вывода на экран

    while(TRUE) {

        SYS_doVBlankProcess();

		VDP_clearTextArea(0, 1, 40, 13);

		
        //опрос мыши
        Z80_HALT = 0x0100;
        *MOUSE_PORT = 0x60; delay();

		nibbles[0] = *MOUSE_PORT & 0x0F;


        for(int i=1;i<10;i++) {
            *MOUSE_PORT = (i&1)?0x20:0x00;
            delay();
            nibbles[i] = *MOUSE_PORT & 0x0F;
            delay();
        }

        *MOUSE_PORT = 0x60; delay();
        Z80_HALT = 0x0000;
		//конец опроса мыши

        // выводим нибблы на экран
		sprintf(buf, "%X%X%X%X %X %X %X%X %X%X", nibbles[0],nibbles[1],nibbles[2],nibbles[3],nibbles[4],nibbles[5],nibbles[6],nibbles[7],nibbles[8],nibbles[9]);
		VDP_drawText(buf, 13,1);

        //считаем dx dy 
		s16 dx = (nibbles[6] << 4) | nibbles[7];
		s16 dy = (nibbles[8] << 4) | nibbles[9];
		if (nibbles[4]&8) dy = 255;
		if (nibbles[4]&4) dx = 255;
		if (nibbles[4]&2) dy = dy|0xFF00; //sign-extend to 16-bit
		if (nibbles[4]&1) dx = dx|0xFF00;
		x+=dx;
		y+=dy;

		//выводим на экран полезные данные
		sprintf(buf, "buttons: %c%c%c%c", (nibbles[5]&8&&1)+'0',(nibbles[5]&4&&1)+'0',(nibbles[5]&2&&1)+'0',(nibbles[5]&1&&1)+'0');
		VDP_drawText(buf, 2, 10);
		sprintf(buf, "dx: %+04d dy: %+04d x: %+04d y: %+04d", dx,dy,x,y);
		VDP_drawText(buf, 2, 12);
		
    }

    return 0;
}