Help needed to get my 7i76E + 7i85S + 7i73 on my mill going.

FUNCTION(_){
	int actual, message, motor_max_speed;
	int i;
	// These need to be edited to suit the gearbox
	int speeds[12]    = {0,    255,  325,  430,  540,  715,  900,  1190,  1500,  2000, 2500, 0x1P30};
	int reqd_gear[12] = {0x0, 0x01, 0x21, 0x02, 0x22, 0x04, 0x24,  0x08,  0x28,  0x10, 0x30, 0x0};
	if (spindle_speed_in == 0) return;
	actual = (gear_high * 0x20  + gear_A * 0x10 + gear_B * 0x08  + gear_C * 0x04 + gear_D * 0x02 + gear_E * 0x01);
	for (i = 0; spindle_speed_in > speeds[i] && i < 10; i++);
	gear_required = reqd_gear[i];
	if (gear_required == actual && gear_required != 0x0){ // We are in the right gear
		spindle_enable_out = spindle_enable_in;
		motor_speed_out = speeds[10] * (spindle_speed_in / speeds[i+1]);
		message = 0;
	} else {
                int j;
		motor_speed_out = 0;
		spindle_enable_out = 0;
		for (j = 0; j < 10; j++) { message(j) = 0; }
                message(i) = 1;
	}
}

motor_speed_out = speeds[10] * (spindle_speed_in / speeds[i+1]);

correct line
motor_speed_out = speeds[10] * (spindle_speed_in / speeds[i]);