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-rw-r--r--include/kernel/io.h10
-rw-r--r--kernel/io.c72
2 files changed, 82 insertions, 0 deletions
diff --git a/include/kernel/io.h b/include/kernel/io.h
new file mode 100644
index 0000000..bef87af
--- /dev/null
+++ b/include/kernel/io.h
@@ -0,0 +1,10 @@
+#ifndef IO_H
+#define IO_H
+
+#include <kernel/tty.h>
+#include <stdarg.h>
+
+int vprintf(const char *fmt, va_list args);
+int printf(const char *fmt, ...);
+
+#endif
diff --git a/kernel/io.c b/kernel/io.c
new file mode 100644
index 0000000..ca787b3
--- /dev/null
+++ b/kernel/io.c
@@ -0,0 +1,72 @@
+#include <kernel/io.h>
+#include <kernel/string.h>
+
+char* convert(unsigned int num, int base) {
+ static char rep[] = "0123456789ABCDEF";
+ static char buffer[50];
+ char *ptr;
+
+ ptr = &buffer[49];
+ *ptr = '\0';
+
+ do {
+ *--ptr = rep[num%base];
+ num /= base;
+ } while (num != 0);
+
+ return ptr;
+}
+
+int vprintf(const char *fmt, va_list args) {
+ char *traverse;
+ char *s;
+ int i;
+
+ for (traverse = fmt; *traverse != '\0'; traverse++) {
+ if (*traverse != '%') {
+ tty_putchar(*traverse);
+ continue;
+ } else {
+ traverse++;
+ }
+
+ switch (*traverse) {
+ case 'c':
+ i = va_arg(args, int);
+ tty_putchar(i);
+ break;
+ case 'd':
+ i = va_arg(args, int);
+ if (i < 0) {
+ i = -i;
+ tty_putchar('-');
+ }
+ tty_writestring(convert(i, 10));
+ break;
+ case 'o':
+ i = va_arg(args, unsigned int);
+ tty_writestring(convert(i, 8));
+ break;
+ case 's':
+ s = va_arg(args, char*);
+ tty_writestring(s);
+ break;
+ case 'x':
+ i = va_arg(args, unsigned int);
+ tty_writestring(convert(i, 16));
+ break;
+ }
+ }
+ return 0;
+}
+
+int printf(const char *fmt, ...) {
+ va_list args;
+ int done;
+
+ va_start(args, fmt);
+ done = vprintf(fmt, args);
+ va_end(args);
+
+ return done;
+}