Changeset 31 for trunk/BOOTCODE/REGULAR/OTHER.ASM

Timestamp:

Jan 13, 2013, 8:15:35 AM (13 years ago)

Author:

Ben Rietbroek

Message:

Bumped code-version to v1.0.8 [2011-11-11]

Fixes

o Fixed the drive-letter feature that was broken in v1.07
o Corrected release date in signature which was not updated with v1.07

Changes

o Bumped code-version in signature to v1.0.8

The extra dot is cosmetic only, the version in the signature
is BCD-coded and did not change format.

o Reworked MBR code to contain two I13X signatures

These signatures are actually MOV EAX,'X31I' in the original eCS
LVM MBR-code. However, they are at different offsets in the v1.x
and v2.x versions of the LVM MBR-code. (v1.x->0d5h -- v2.x->0d0h)
Other code might depend on their existence so we put both in
the AiR-BOOT MBR. (See eCS bugtracker issue #3002)

Note

This commit and all following commits upto and including the RC3
commit [2012-09-09] are delayed commits from a local repository.
Also, the RC (Release Candidate) naming of the corresponding commits
is a bit misleading. One would label a revision with RC when near to
a final release. Since many things have changed between RC1,RC2 & RC3,
these RC's should be interpreted as mile-stones.

WARNING!!

All commits upto and including the commit of [2012-05-13] contain
a severe bug!! Building from these sources and then disabling
the 'force LBA' feature while also using the drive-letter feature or
editing the label can destroy the MBR on all attached disks!!
DO NOT DISABLE 'FORCE LBA USAGE' WHEN BUILT FROM THE ABOVE COMMITS!!

File:

• trunk/BOOTCODE/REGULAR/OTHER.ASM (modified) (1 diff)

trunk/BOOTCODE/REGULAR/OTHER.ASM

@@ -363 +363 @@
    mov     si, offset Configuration
    xor     bx, bx
-   mov     cx, 5                   ; Total of 5 Sectors
+
+   ; Changed from 5 to calculated
+   ; Fixes issue: #2987 -- "air-boot doesn't remember drive letter"
+   mov     cx, (MBR_BackUpMBR - Configuration) / 2   ; Size of the ab-configuration
+   ; TASM does not evaluate expression above corrrectly.
+   ; Listing shows correct opcode but generated opcode has imm. word byteswapped.
+   ; Casting to byte also does not work (overflow).
+   ; So we swap back here -- must be removed in JWasm version !!
+      xchg  ch,cl
+
    mov     dx, CFG_CheckConfig
    mov     CFG_CheckConfig, bx