Fix sleep_and_quit_on_keypress on BIOS
diff --git a/stage23/lib/sleep.asm b/stage23/lib/sleep.asm
index 11a35900..3ba4ed01 100644
--- a/stage23/lib/sleep.asm
+++ b/stage23/lib/sleep.asm
@@ -105,8 +105,13 @@ pit_sleep_and_quit_on_keypress:
mov edx, dword [int_08_callback]
mov dword [0x08*4], edx
+ xor edx, edx
+ mov dl, ah
+ xor ah, ah
push eax
+ push edx
call getchar_internal
pop edx
+ pop edx
ret
