lesson 17, video scroll

17-video-scroll/kernel/kernel.c

@@ -0,0 +1,17 @@
+#include "../drivers/screen.h"
+#include "util.h"
+
+void main() {
+    clear_screen();
+
+    /* Fill up the screen */
+    int i = 0;
+    for (i = 0; i < 24; i++) {
+        char str[255];
+        int_to_ascii(i, str);
+        kprint_at(str, 0, i);
+    }
+
+    kprint_at("This text forces the kernel to scroll. Row 0 will disappear. ", 60, 24);
+    kprint("And with this text, the kernel will scroll again, and row 1 will disappear too!");
+}

17-video-scroll/kernel/util.c

@@ -0,0 +1,23 @@
+void memory_copy(char *source, char *dest, int nbytes) {
+    int i;
+    for (i = 0; i < nbytes; i++) {
+        *(dest + i) = *(source + i);
+    }
+}
+
+/**
+ * K&R implementation
+ */
+void int_to_ascii(int n, char str[]) {
+    int i, sign;
+    if ((sign = n) < 0) n = -n;
+    i = 0;
+    do {
+        str[i++] = n % 10 + '0';
+    } while ((n /= 10) > 0);
+
+    if (sign < 0) str[i++] = '-';
+    str[i] = '\0';
+
+    /* TODO: implement "reverse" */
+}

17-video-scroll/kernel/util.h

@@ -0,0 +1,2 @@
+void memory_copy(char *source, char *dest, int nbytes);
+void int_to_ascii(int n, char str[]);