Changeset 549 in xtideuniversalbios for trunk

Timestamp:

Apr 22, 2013, 10:32:25 AM (12 years ago)

Author:

aitotat@…

google:author:

aitotat@gmail.com

Message:

Changes to XTIDE Universal BIOS:

• Assited LBA is now the default geometry translation mode if MODULE_EBIOS is defined and drive supports LBA.
• P-Heads are now limited to 15 only when LARGE mode requires Revised ECHS translation.

Location:

trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs

Files:

• AtaGeometry.asm (modified) (5 diffs)
• CreateDPT.asm (modified) (2 diffs)

trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/AtaGeometry.asm

@@ -65 +65 @@
 
 ;--------------------------------------------------------------------
-; AtaGeometry_GetLCHStoAXBLBHfromAtaInfoInESSIandTranslateModeInDX
+; AtaGeometry_GetLCHStoAXBLBHfromAtaInfoInESSIwithTranslateModeInDX
 ;   Parameters:
 ;       DX:     Wanted translate mode or TRANSLATEMODE_AUTO to autodetect
@@ -78 +78 @@
 ;       DH
 ;--------------------------------------------------------------------
-AtaGeometry_GetLCHStoAXBLBHfromAtaInfoInESSIandTranslateModeInDX:
+AtaGeometry_GetLCHStoAXBLBHfromAtaInfoInESSIwithTranslateModeInDX:
     call    AtaGeometry_GetPCHStoAXBLBHfromAtaInfoInESSI
 
@@ -92 +92 @@
     ; TRANSLATEMODE_AUTO set
 
+%ifndef MODULE_EBIOS
+    ; Since we do not have EBIOS functions, we might as well use the faster
+    ; LARGE mode for small drives. Assisted LBA provides more capacity for
+    ; larger drives.
     ; Generate L-CHS using simple bit shift algorithm (ECHS) if
     ; 8192 or less cylinders.
     cmp     ax, 8192
     jbe     SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL
-
-    ; We have 8193 or more cylinders so two algorithms are available:
-    ; Revised ECHS or Assisted LBA. The Assisted LBA provides larger
-    ; capacity but requires LBA support from drive (drives this large
-    ; always support LBA but user might have unintentionally set LBA).
-.UseAssistedLBA:
+%endif
+
+    ; If we have EBIOS functions, we should always use Assisted LBA
+    ; for drives with LBA support. Otherwise the EBIOS functions are
+    ; useless since we never do LBA to P-CHS translation.
+    ; Even if we do not have EBIOS functions, we must do this check
+    ; since user might have forced LBA mode even though the drive does
+    ; not support LBA addressing.
     test    BYTE [es:si+ATA1.wCaps+1], A1_wCaps_LBA>>8
     jz      SHORT ConvertPCHfromAXBLtoRevisedEnhancedCHinAXBL
 
-    ; Drive supports LBA
+    ; Assisted LBA provides most capacity but translation algorithm is
+    ; slower. The speed difference doesn't matter on AT systems.
+.UseAssistedLBA:
     call    GetSectorCountToDXAXfromCHSinAXBLBH
     call    ConvertChsSectorCountFromDXAXtoLbaAssistedLCHSinAXBLBH
@@ -183 +191 @@
     ; Generate L-CHS using simple bit shift algorithm (ECHS) if
     ; 8192 or less cylinders
-    cmp     ax, 8192
-    jbe     SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL
-    cmp     bl, 16  ; Drives with 8193 or more cylinders can report 15 heads
-    jb      SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL
+    call    AtaGeometry_IsDriveSmallEnoughForECHS
+    jc      SHORT ConvertPCHfromAXBLtoEnhancedCHinAXBL
 
     eMOVZX  cx, bl  ; CX = 16
@@ -239 +245 @@
     mov     dl, TRANSLATEMODE_LARGE
     jmp     SHORT .ShiftIfMoreThan1024Cylinder
+
+
+;--------------------------------------------------------------------
+; Checks should LARGE mode L-CHS be calculated with ECHS or Revised ECHS
+; algorithm. Revised ECHS is needed for drives with 8193 or more cylinders
+; AND 16 heads.
+;
+; AtaGeometry_IsDriveSmallEnoughForECHS:
+;   Parameters:
+;       AX:     Number of P-Cylinders
+;       BL:     Number of P-Heads
+;   Returns:
+;       CF:     Clear if Reviced ECHS is necessary
+;               Set if ECHS is enough
+;   Corrupts registers:
+;       Nothing
+;--------------------------------------------------------------------
+AtaGeometry_IsDriveSmallEnoughForECHS:
+    ; Generate L-CHS using simple bit shift algorithm (ECHS) if
+    ; 8192 or less cylinders. Use Revised ECHS if 8193 or more cylinders
+    ; AND 16 heads.
+    cmp     ax, 8193
+    jb      SHORT .RevisedECHSisNotNeeded
+    cmp     bl, 16  ; Drives with 8193 or more cylinders can report 15 heads
+.RevisedECHSisNotNeeded:
+    ret
 
 

trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/CreateDPT.asm

@@ -100 +100 @@
 
     ; Translate P-CHS to L-CHS
-    call    AtaGeometry_GetLCHStoAXBLBHfromAtaInfoInESSIandTranslateModeInDX
+    call    AtaGeometry_GetLCHStoAXBLBHfromAtaInfoInESSIwithTranslateModeInDX
     mov     [di+DPT.wLchsCylinders], ax
     mov     [di+DPT.wLchsHeadsAndSectors], bx
@@ -113 +113 @@
     jz      SHORT .LimitHeadsForLargeAddressingMode
 
-    or      cl, FLGL_DPT_LBA        ; Set LBA bit for Assisted LBA
+    ; Set LBA bit for Assisted LBA
+    or      cl, FLGL_DPT_LBA
     jmp     SHORT .NothingToChange
+
 .LimitHeadsForLargeAddressingMode:
-    MIN_U   bl, 15                  ; Cannot have 16 P-Heads in LARGE addressing mode
+    ; We cannot have 16 P-Heads heads in Revised ECHS mode (8193 or more cylinders)
+    ; but 16 heads are allowed when there are 8192 or less cylinders (ECHS).
+    ; Both of these are LARGE modes so do not confuse with NORMAL mode.
+    call    AtaGeometry_IsDriveSmallEnoughForECHS
+    jc      SHORT .NothingToChange
+    dec     bx                      ; Adjust 16 P-Heads to 15
+
 .NothingToChange:
     or      [di+DPT.bFlagsLow], cl  ; Shift count and addressing mode