/* write a null terminated string at the current cursor position. handles \n for newlines. */
void terminal_write(char *string) {
for (size_t index = 0; string[index] != 0; index++) {
if (string[index] == '\n') {
vga_move_cursor(0, ++cursor_row);
} else {
VGA_MEMORY[vga_cursor_memory_index()] = vga_character(string[index]);
vga_move_cursor(++cursor_column, cursor_row);
}
}
}
/* clear the terminal and move the cursor back to the top left */
void terminal_clear() {
for (uint8_t row = 0; row < VGA_HEIGHT; row++) {
for (uint8_t column = 0; column < VGA_WIDTH; column++) {
VGA_MEMORY[row * VGA_WIDTH + column] = vga_character(' ');
}
}
vga_move_cursor(0, 0);
}
static void vga_clear(void)
{
memset(vga.base, 0, VGA_ROWS * VGA_COLUMNS * 2);
vga_move_cursor(0, 0);
}
int vga_putchar(int c)
{
uint_t row;
uint_t column;
int print_action;
int post_action;
int move_action;
if (!initialized) {
return EOF;
}
/* Retrieve the old cursor position */
row = vga.row;
column = vga.column;
print_action = 1;
move_action = 1;
post_action = 1;
/* Pre-print action */
switch (c) {
case '\a': /* Bell */
/* Missing */
break;
case '\b': /* Back Space */
column = column - 1;
c = ' ';
print_action = 1;
post_action = 0;
break;
case '\t': /* Tab */
column = column + 8;
print_action = 0;
post_action = 0;
break;
case '\v': /* Vertical Tab ? */
/* missing */
break;
case '\n': /* New Line */
row = row + 1;
column = 0;
print_action = 0;
post_action = 0;
break;
case '\f': /* Form Feed */
row = row + 1;
print_action = 0;
post_action = 0;
break;
case '\r': /* Line Feed */
column = 0;
print_action = 0;
post_action = 0;
break;
default:
print_action = isprint(c);
post_action = print_action;
break;
}
check_bounds(&column, &row);
/* Print */
if (print_action) {
vga_putc(c, row, column);
}
/* Post-print action */
if (post_action) {
switch (c) {
default:
column = column + 1;
break;
}
}
check_bounds(&column, &row);
/* Move */
if (move_action) {
vga_move_cursor(row, column);
}
/* Save the final cursor position */
vga.row = row;
vga.column = column;
return (unsigned char) c;
}
