static void check_bounds(uint_t* column, uint_t* row)
{
uint_t r;
uint_t c;
r = *row;
c = *column;
if (c >= VGA_COLUMNS) {
/* We reached the right margin ... */
c = 0;
r = r + 1;
}
#if 0
/* Huh ... c is an unit_t */
else if (c < 0) {
c = VGA_COLUMNS - 1;
r = r - 1;
}
#endif
if (r >= VGA_ROWS) {
/* We reached the bottom margin */
r = VGA_ROWS - 1;
/* And we need to scroll up the screen */
vga_scroll_up();
}
#if 0
/* Huh ... r is an unit_t */
else if (r < 0) {
r = 0;
}
#endif
*column = c;
*row = r;
}
void vga_putc (const char c)
{
unsigned short *vptr = (unsigned short *)VMEM_BASE;
unsigned char backcolor = 0;
unsigned char forecolor = 15;
unsigned char vattr = (u8)((backcolor << 4) | (forecolor));
unsigned short vval = (u16)((vattr << 8) | (c));
unsigned int location_offset;
if (cursor_y == max_y){
vga_scroll_up ();
}
location_offset = (unsigned)((cursor_y * 80) + cursor_x);
switch (c){
case '\n':
cursor_x = 0;
cursor_y++;
if (cursor_y != max_y)
move_cursor (cursor_x, cursor_y);
break;
case '\t':
cursor_x = (u8)(cursor_x + KTabWidth);
if (cursor_x >= 80){
cursor_x = 0;
cursor_y++;
}
if (cursor_y >= max_y)
vga_scroll_up ();
else
move_cursor (cursor_x, cursor_y);
break;
case '\r': // carriage return
cursor_x = 0;
cursor_y++;
move_cursor (cursor_x, cursor_y);
break;
case '\b':
if(cursor_x > 0) {
cursor_x--;
move_cursor(cursor_x, cursor_y);
}
break;
default:
*(volatile unsigned short*)(vptr + location_offset) = vval;
cursor_x++;
if (cursor_x == max_x){
cursor_x = 0;
cursor_y++;
}
/*
if (cursor_y >= max_y)
vga_scroll_up ();
else*/
if (cursor_y != max_y)
move_cursor (cursor_x, cursor_y);
break;
}
}
void vga_cursor_down() {
if (++vga_state.vga_pos_y >= vga_state.vga_height) {
vga_state.vga_pos_y = vga_state.vga_height - 1;
vga_scroll_up(1);
}
}
