Add some comments to the MBR

diff --git a/mbr/mbr.S b/mbr/mbr.S
index ecab4e9..854e39b 100644 (file)
--- a/mbr/mbr.S
+++ b/mbr/mbr.S
@@ -218,7 +218,7 @@ scan_partition_table:
        call    scan_partition_table
 11:
        /* This returned, so we need to reload the current partition table */
-       movl    28(%bp), %eax
+       movl    28(%bp), %eax           /* "Base" */
        call    read_partition_table
 
        /* fall through */
@@ -238,10 +238,10 @@ scan_partition_table:
 boot:
        movl    8(%si), %eax
        addl    28(%bp), %eax
-       movl    %eax, 8(%si)
+       movl    %eax, 8(%si)    /* Adjust in-memory partition table entry */
        pushw   %si
        call    read_sector
-       popw    %si
+       popw    %si             /* ds:si -> partition table entry */
        jc      disk_error
        cmpw    $0xaa55, (bootsec+510)
        jne     missing_os              /* Not a valid boot sector */