Changeset 558 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h/AH24h_HSetBlocks.asm

Timestamp:

Jun 23, 2013, 3:52:31 PM (12 years ago)

Author:

krille_n_@…

google:author:

krille_n_@hotmail.com

Message:

Changes:

• Building the BIOS Drive Information Tool now works again.
• Moved all XT-CF related code to MODULE_8BIT_IDE_ADVANCED. I don't see how an XT-CF card could work without *_ADVANCED anyway but if I'm wrong, feel free to undo this. Note! The autodetection code in XTIDECFG has NOT been changed to reflect this (still relies on MODULE_8BIT_IDE).
• Optimizations and fixes in general.

File:

• trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h/AH24h_HSetBlocks.asm (modified) (1 diff)

trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h/AH24h_HSetBlocks.asm

@@ -84 +84 @@
     pop     bx          ; Pop block size to BL
     jc      SHORT .DisableBlockMode
-    mov     bh, bl      ; BL and BH both have block size we tried to set
-    dec     bh
-    jz      SHORT .DisableBlockMode
+
+    ; All valid block sizes are powers of 2 which means BL have just one bit set (parity odd).
+    ; Incrementing BX will cause all block sizes except 1 to have two bits set (parity even).
+    ; Note that PF reflects only the lowest 8 bits of any register being modified.
+    inc     bx                      ; 1 -> 2 ?
+    jpo     SHORT .DisableBlockMode ; Jump if BL = 2
+    dec     bx                      ; Restore block size (was larger than 1)
 
     ; Enable block mode and store block size