// Driver implementation for Jank's text frame buffer

// Buffer can display 80 columns by 25 Rows
// Start of buffer is at (real)address 0x000B8000
// Memory at this section is divided into 16-bit cells 
    // | 15-8 | 7-4 | 0-3
    // | Asci | FG  | BG
// The following colors are available(from 0x0 to 0xF):
    // Black Blue Green Cyan Red Magenta 
    // Brown LightGrey DarkGrey LightBlue LightGreen
    // LightCyan LightRed LightMagenta LightBrown White

/*
enum typedef Colors{
    Black, Blue, Green,
    Cyan, Red, Magenta,
    Brown, LightGrey, DarkGrey,
    LightBlue, LightGreen, LightCyan,
    LightRed, LightMagenta, LightBrown,
    White,
};
*/
#include "framebuffer.h"

static char* Frame_Buffer = (char*)FRAME_BUFFER_ADDR;
static char* Frame_Buffer_End = (char*)(FRAME_BUFFER_ADDR + AREA);
// Writes character to a given cell in the framebuffer
    // Safety handled by caller function 
	// also proper location is caller's responsibility
void write_cell(unsigned cell, char c, char fg, char bg) {
    Frame_Buffer[cell] = c;
    Frame_Buffer[cell+1] = (fg & 0x0f << 4) | (bg & 0x0f);
}

void clear_buffer() {
	char* fp = Frame_Buffer;
	while(fp!=Frame_Buffer_End) {
		*fp = 0x00;
	}
}
static void print(char* str) {
	unsigned idx = 0;
	char* c = str;
	while(c != 0x00) {
		write_cell(idx, *c, Green, White);
		idx += 2;
	}
}

void yote() {
	print("			JankOS			");
}