/* Copyright (c) 1997-2017, FenixOS Developers
 All Rights Reserved.

 This file is subject to the terms and conditions defined in
 file 'LICENSE', which is part of this source code package.
 */

/*! \file video.c This file holds implementations of functions
 presenting output to the VGA screen. */
#include <stdint.h>

/*! Max number of columns in the VGA buffer. */
#define MAX_COLS                (80)
/*! Max number of columns in the VGA buffer. */
#define MAX_ROWS                (25)

struct screen_position {
	unsigned char character; /*!< The character part of the byte tuple used for
	 each screen position. */
	unsigned char attribute; /*!< The character part of the byte tuple used for
	 each screen position. */
};
/*!< Defines a VGA text mode screen position. */

struct screen {
	struct screen_position positions[MAX_ROWS][MAX_COLS];
/*!< The VGA screen. It is organized as a two dimensional array. */
};
/*!< Defines a VGA text mode screen. */

/*! points to the VGA screen. */
static struct screen* const screen_pointer = (struct screen*) 0xB8000;
uint16_t const colorByte = 0x0f;

void printCharArray(const char* string, uint16_t x,uint16_t y) {
	volatile uint16_t * location;
	uint16_t newy = y;
	uint16_t newx = x;
	location = (volatile uint16_t *)0xB8000 + (y * 80 + x);
	newx++;
	if (newx == 80) {
		newx = 0;
		newy++;
	}
	*location = *string | colorByte << 8;
	if (*string+1 == '/n') {
		printCharArray(string + 2, newx, newy + 1);
	} else if (*string+1 != '/0') {
		printCharArray(string + 1, newx, newy);
	}
}

void kprints(const char* string) {
	uint16_t y = 0;
	uint16_t x = 0;
	printCharArray(string, x, y);
}

void kprinthex(const register uint32_t value) {
	volatile uint16_t * location;
	location = (volatile uint16_t *)0xB8000 ;
	uint16_t number = 0;
	uint32_t newValue = value;
	while (newValue) {
		uint16_t temp = value == '1' ? 1 : 0;
		number = (value << 1) | temp;
		newValue = newValue << 1;
	}
	*location = number | colorByte << 8;
}