kfs: fixed printk

every character to be displayed on the screen is two bytes long, not one

Signed-off-by: Olivier Gayot <duskcoder@gmail.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/src/main.c b/src/main.c
index e4d3b4e..7c1172c 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,5 +1,6 @@
 #define NB_COLS 80
 #define NB_ROWS 25
+#define BPC     2
 
 #define VIDEO_BUFFER 0xB8000
 
@@ -32,14 +33,15 @@ int printk(const char *str)
     for (int i = 0; str[i]; ++i) {
         /* TODO add the serial port handling */
 
-        if ((long)addr >= offset + NB_COLS * NB_ROWS) {
+        if ((long)addr >= offset + NB_COLS * NB_ROWS * BPC) {
             /* shift up */
-            addr -= NB_COLS;
-            my_memmove((void *)offset, (void *)offset + NB_COLS, NB_COLS * (NB_ROWS - 1));
-            my_memset((void *)offset + NB_COLS * (NB_ROWS - 1), ' ', NB_ROWS);
+            addr -= NB_COLS * BPC;
+            my_memmove((void *)offset, (void *)offset + NB_COLS * BPC, NB_COLS * (NB_ROWS - 1) * BPC);
+            my_memset((void *)offset + NB_COLS * (NB_ROWS - 1) * BPC, ' ', NB_COLS * BPC);
         }
 
-        *addr++ = str[i];
+        *addr = str[i];
+        addr += BPC;
         ++count;
     }