#include "screen.h"
#include <cpu-io.h>

void scrollup(unsigned int n)
{
	unsigned char *video, *tmp;

	for(video = (unsigned char *) RAMSCREEN; video < (unsigned char *) SCREENLIM; video += 2) 
	{
		tmp = (unsigned char *) (video + n * 160);

		if(tmp < (unsigned char *) SCREENLIM) 
		{
			*video = *tmp;
			*(video + 1) = *(tmp + 1);
		} else 
		{
			*video = 0;
			*(video + 1) = 0x07;
		}
	}

	kY -= n;

	if(kY < 0)
		kY = 0;
}

void putcar(uint8_t c)
{
	unsigned char *video;

	if(c == 10)             /* CR-NL */
	{		
		kX = 0;
		kY++;
	} 
	else if(c == 9)  	/* TAB */
	{
		kX = kX + 8 - (kX % 8);
	} 
	else if(c == 13)        /* CR */ 
	{	
		kX = 0;
	} 
	else
	{		
		video  = (unsigned char *) (RAMSCREEN + 2 * kX + 160 * kY);
		*video = c;
		*(video + 1) = kattr;

		kX++;
		if (kX > 79) 
		{
			kX = 0;
			kY++;
		}
	}

	if (kY > 24)
		scrollup(kY - 24);
}

void move_cursor(uint8_t x, uint8_t y)
{
	uint16_t c_pos;

	c_pos = y * 80 + x;

	cpu_io_out8(0x3d4, 0x0f);
	cpu_io_out8(0x3d5, (uint8_t) c_pos);
	cpu_io_out8(0x3d4, 0x0e);
	cpu_io_out8(0x3d5, (uint8_t) (c_pos >> 8));
}

void show_cursor(void)
{
	move_cursor(kX, kY);
}

void hide_cursor(void)
{
	move_cursor(-1, -1);
}

void dump (uint8_t* addr, int n)
{
	char c1, c2;
	char *tab = "0123456789ABCDEF";
	
	while(n--) {
		c1 = tab[(*addr & 0xF0)>>4];
		c2 = tab[*addr & 0x0F];
		addr++;
		putcar(c1);
		putcar(c2);
	}
}