//function to print a character to the screen
void print_char(char character, int row, int col, char attribute){
//pointer to start of video memory
unsigned char* vidmem = (unsigned char*) VID_ADDR;
//default color scheme
if (!attribute){
attribute = WHIT_BLK;
}
//memory offset
int offset;
// if row and col < 0, offset is cursor
if (col >= 0 && row >= 0){
offset = get_screen_offset(col, row);
}
else {
offset = get_cursor();
}
int backspace = 0;
if (character == '\b'){
//backspace
offset -= 2;
character = ' ';
backspace = 1;
}
if (character == '\n'){
//new line
int rows = offset / (2 * MAX_COLS);
offset = get_screen_offset(79, rows);
}
else{
unsigned char* locale = vidmem + offset;
unsigned char* attr_locale = vidmem + offset + 1;
*locale = character;
*attr_locale = attribute;
}
if (backspace == 0){
offset += 2;
}
offset = handle_scrolling(offset);
set_cursor(offset);
}
/*
Print a char on the screen at col, row, or at cursor position
*/
void print_char(char nChar, int nCol, int nRow, char nAttribute)
{
unsigned char * pVidMem = (unsigned char*) VIDEO_ADDRESS;
if (!nAttribute)
{
nAttribute = WHITE_ON_BLACK;
}
int offset = 0;
// if (nCol >= 0 && nRow >= 0)
// {
// offset = get_screen_offset(nCol, nRow);
// }
// else
// {
offset = get_cursor();
// }
if (nChar == '\n')
{
int rows = offset / (2*MAX_COLS);
offset = get_screen_offset(79, rows);
offset += 2;
}
else
{
pVidMem[offset] = nChar;
pVidMem[offset + 1] = nAttribute;
offset += 2;
}
offset = handle_scrolling(offset);
set_cursor(offset);
}
/* Print a char on the screen at col , row , or at cursor position */
void print_char(const char character, int col, int row, char attribute_byte)
{
/* Create a byte ( char ) pointer to the start of video memory */
unsigned char volatile *vidmem = VIDEO_ADDRESS;
/* If attribute byte is zero , assume the default style . */
if (!attribute_byte) {
attribute_byte = WHITE_ON_BLACK;
}
/* Get the video memory offset for the screen location */
int offset;
/* If col and row are non - negative , use them for offset . */
if (col >= 0 && row >= 0) {
offset = get_screen_offset(col, row);
/* Otherwise , use the current cursor position . */
} else {
offset = get_cursor();
}
// If we see a newline character , set offset to the end of
// current row , so it will be advanced to the first col
// of the next row.
if (character == '\n') {
int rows = offset / (2 * MAX_COLS);
offset = get_screen_offset(79, rows);
// Otherwise , write the character and its attribute byte to
// video memory at our calculated offset .
} else {
vidmem[offset] = character;
vidmem[offset + 1] = attribute_byte;
}
// Update the offset to the next character cell , which is
// two bytes ahead of the current cell .
offset += 2;
// Make scrolling adjustment , for when we reach the bottom
// of the screen .
offset = handle_scrolling(offset);
// Update the cursor position on the screen device .
set_cursor(offset);
}
