Add sanity check panic for CRTC interactions

2015-11-07 00:38:40 -05:00 · 2015-11-07 00:38:40 -05:00 · 02530a4859
parent b019ac4f7d
commit 02530a4859
1 changed files with 3 additions and 0 deletions
--- a/console.c
+++ b/console.c
@ -143,6 +143,9 @@ cgaputc(int c)
    if(pos > 0) --pos;
  } else
    crt[pos++] = (c&0xff) | 0x0700;  // black on white
+
+  if(pos > 25*80)
+    panic("pos overflow");
  
  if((pos/80) >= 24){  // Scroll up.
    memmove(crt, crt+80, sizeof(crt[0])*23*80);