Get the actual high paragraph rather than just blindly reporting 64K

diff --git a/comboot.inc b/comboot.inc
index 5e1d8e9..d358147 100644 (file)
--- a/comboot.inc
+++ b/comboot.inc
@@ -92,7 +92,11 @@ is_comboot_image:
 
                mov word [es:0], 020CDh ; INT 20h instruction
                ; First non-free paragraph
-               mov word [es:02h], comboot_seg+1000h
+               ; This is valid because comboot_seg == real_mode_seg
+               ; == the highest segment used by all derivatives
+               int 12h                 ; Get DOS memory size
+               shl ax,6                ; Kilobytes -> paragraphs
+               mov word [es:02h],ax
 
                ; Copy the command line from high memory
                mov cx,125              ; Max cmdline len (minus space and CR)