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#include "print.h"
#include "str.h"
#include <stdarg.h>
// Constants
static const size_t NUM_COLS = 80;
static const size_t NUM_ROWS = 25;
// Char struct
struct Char {
uint8_t character;
uint8_t color;
};
// Set video mem buffer
struct Char *buffer = (struct Char *)0xb8000;
// Set current row and col
size_t col = 0;
size_t row = 0;
// Default colors
uint8_t color = PRINT_COLOR_WHITE | PRINT_COLOR_BLACK << 4;
// clear row
void clear_row(size_t row) {
// Define empty character
struct Char empty = (struct Char){
' ',
color,
};
// For every col in row, set vmem to empty
for (size_t col = 0; col < NUM_COLS; col++) {
buffer[col + NUM_COLS * row] = empty;
}
}
// Call clear_row for every row
void print_clear() {
for (size_t i = 0; i < NUM_ROWS; i++) {
clear_row(i);
}
}
// newline
void print_newline() {
// Reset col and iterate row if not at bottom of screen
col = 0;
if (row < NUM_ROWS - 1) {
row++;
return;
}
// If at bottom of screen, move all the text up one row
for (size_t row = 1; row < NUM_ROWS; row++) {
for (size_t col = 0; col < NUM_COLS; col++) {
struct Char character = buffer[col + NUM_COLS * row];
buffer[col + NUM_COLS * (row - 1)] = character;
}
}
// Clear
clear_row(NUM_ROWS - 1);
}
// printchar
void print_char(char character) {
// If \n, call newline
if (character == '\n') {
print_newline();
return;
}
if (character == '\t') {
print_str(" \0");
return;
}
// if cols is too large, overflow
if (col > NUM_COLS) {
print_newline();
}
// set video memeory to requested character
buffer[col + NUM_COLS * row] = (struct Char){
(uint8_t)character,
color,
};
// iterate col
col++;
}
// print_str
void print_str(char *str) {
// while character != '\0' print char
for (size_t i = 0; str[i] != '\0'; ++i)
print_char(str[i]);
}
// Set color byte to requested colors using color enum from print.h
void print_set_color(uint8_t foreground, uint8_t background) {
color = foreground + (background << 4);
}
void printf(const char *str, ...) {
va_list args;
va_start(args, str);
char temp_str[256];
for (size_t i = 0; str[i] != '\0'; ++i) {
if (str[i] == '%') {
switch (str[++i]) {
case 'i':
case 'd':
print_str(itoa(va_arg(args, int), temp_str));
break;
case 's':
print_str(va_arg(args, char *));
break;
case 'c':
print_char(va_arg(args, int));
break;
case '%':
print_char('%');
case 'n':
break;
}
continue;
}
print_char(str[i]);
}
va_end(args);
}
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