Fix copying of kernel arguments

boot/floppy.asm

@@ -207,15 +207,17 @@ main:
   mov cx, 0x007F
   mov di, arguments
   xor ax, ax
-  repe scasb
+  repne scasb
+  dec di
   sub di, arguments
   mov cx, di
 
   ; setup arguments field
   mov [0x080], cl
-  mov di, [0x081]
+  mov di, 0x081
   mov si, arguments
   rep movsb
+  mov BYTE [di], 0x0D
 
   ; setup int 19h call at 0000, and push its address to stack
   mov WORD [0000], 0x19CD
@@ -249,7 +251,7 @@ filename:
   db "KERNEL  COM"
 
 arguments:
-  db " ", 0
+  db "", 0
 
 times (0x1FE - ($-$$)) db 0