Changeset 173 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Inc

Timestamp:

Sep 18, 2011, 11:41:29 AM (13 years ago)

Author:

aitotat@…

google:author:

aitotat@gmail.com

Message:

Changes to XTIDE Universal BIOS:

• L-CHS parameters are now generated differently for LBA enabled drives.
• Booting to EBIOS partitions now seems to work (at least on one drive).

File:

• trunk/XTIDE_Universal_BIOS/Inc/CustomDPT.inc (modified) (3 diffs)

trunk/XTIDE_Universal_BIOS/Inc/CustomDPT.inc

@@ -6 +6 @@
 
 ; Base DPT for all device types
-struc DPT   ; 8 bytes
+struc DPT   ; 10 bytes
     ; General Disk Parameter Table related
     .wFlags:
@@ -12 +12 @@
     .bFlagsHigh                 resb    1
     .bIdevarsOffset             resb    1   ; Offset to IDEVARS for this drive
-
-    ; L-CHS to P-CHS and L-CHS to LBA28 conversion related
-    .bLchsHeads                 resb    1   ; Number of L-CHS Heads (1...255)
+                                resb    1
 
     ; IDE Drive related
-    .wPchsCylinders             resb    2   ; Number of P-CHS (IDE) Cylinders (1...16383)
-    .wPchsHeadsAndSectors:
-    .bPchsHeads                 resb    1   ; Number of P-CHS (IDE) Heads (1...16)
-    .bPchsSectors               resb    1   ; Number of P-CHS (IDE) Sectors per Track (1...63)
+    .dwCylinders                resb    4   ; Number of Cylinders
+    .wHeadsAndSectors:
+    .bHeads                     resb    1   ; Number of Heads (1...255)
+    .bSectors                   resb    1   ; Number of Sectors per Track (1...63)
 endstruc
 
 ; DPT for ATA devices
-struc DPT_ATA   ; 8 + 2 bytes = 10 bytes
+struc DPT_ATA   ; 10 + 2 bytes = 12 bytes
     .dpt                        resb    DPT_size
 
@@ -61 +59 @@
 ADDRESSING_MODE_LBA48           EQU     3   ; 48-bit LBA Addressing Mode
 
+; Number of Sectors per Track is fixed to 63 for LBA assist calculation.
+; 1024 cylinders, 256 heads, 63 sectors = 8.4 GB limit (but DOS does not support more than 255 heads)
+MAX_LCHS_CYLINDERS              EQU     1024
+LBA_ASSIST_SPT                  EQU     63
+
 
 %endif ; CUSTOMDPT_INC