// 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
#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
    // @cell parameter is the logical (linear)index into the buffer
	// _not_ the actual offset from the buffer addr
	// also proper location is caller's responsibility
void write_cell_fb(unsigned cell, char c, char fg, char bg) {
    Frame_Buffer[cell] = c;
    Frame_Buffer[cell+1] = (fg & 0x0f << 4) | (bg & 0x0f);
}

/*  should be passing in a cell-position for position param*/
void print_fb(char* str, unsigned position) {
	unsigned relative_end = position + strlen(str);
	for(unsigned i = position; i<relative_end; i++) {
		write_cell_fb(FRAME_CELL(i), str[i], Green, White);
	}
}

void clear_fb() {
	for(unsigned cell=0;cell<AREA; cell+=2) {
		write_cell_fb(cell, ' ', 0x00, 0x00);
	}
}
/* generic test func for this module */
void test_fb() {
	clear_fb();
	print_fb("adsf", POSITION(0,5));
}