r577 - ofw/fs/fatfs

Author: wmb
Date: 2007-08-24 01:34:38 +0200 (Fri, 24 Aug 2007)
New Revision: 577

Modified:
   ofw/fs/fatfs/partition.fth
Log:
Followup to r564 - Tighter heuristic for detecting the presence of a
partition map; the old one was treating boot code as partition info.
This new one also requires a couple of specific values (0 or 80) in the
bootable byte.

Modified: ofw/fs/fatfs/partition.fth
===================================================================
--- ofw/fs/fatfs/partition.fth	2007-08-23 23:31:44 UTC (rev 576)
+++ ofw/fs/fatfs/partition.fth	2007-08-23 23:34:38 UTC (rev 577)
@@ -17,8 +17,12 @@
 \ using fdisk and mkdosfs under Linux.  It is too easy to run mkdosfs on
 \ the overall disk (not the partition).
 : unpartitioned?  ( -- flag )
-   sector-buf h# 1fe + le-w@ h# aa55 <>
-   sector-buf h# 1c6 + le-l@ 0=  or
+   \ In partition maps, the status byte is 0 (not bootable) or 80 (bootable)
+   sector-buf h# 1be + c@  h# 7f and  0<>     ( unpartitioned? )
+   \ and the end of the sector contains a signature
+   sector-buf h# 1fe + le-w@ h# aa55 <>  or   ( unpartitioned?' )
+   \ and the first partition entry has a non0 starting sector number
+   sector-buf h# 1c6 + le-l@ 0=  or           ( unpartitioned?' )
 ;

: ptable-bounds  ( -- end start )  sector-buf  h# 1be +  h# 40  bounds  ;