Changeset 542 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h

Timestamp:

Apr 15, 2013, 4:03:33 PM (12 years ago)

Author:

aitotat@…

google:author:

aitotat@gmail.com

Message:

Changes to XTIDE Universal BIOS:

• Fixed a bug that allowed EBIOS functions for user defined CHS.
• Simplified user defined CHS and LBA setup a little.

Location:

trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h

Files:

• AH9h_HInit.asm (modified) (2 diffs)
• EBIOS/AH48h_GetExtendedDriveParameters.asm (modified) (2 diffs)
• Tools/Address.asm (modified) (1 diff)

trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h/AH9h_HInit.asm

@@ -99 +99 @@
 ;;; SelectDrive
     ; Try to select drive and wait until ready
-    call    AccessDPT_GetDriveSelectByteForOldInt13hToAL
+    call    AccessDPT_GetDriveSelectByteToAL
     mov     [bp+IDEPACK.bDrvAndHead], al
     call    Device_SelectDrive
@@ -130 +130 @@
 
 ;;; InitializeDeviceParameters
-    ; Initialize CHS parameters if LBA is not used and
-    ; user has specified P-CHS parameters
-    test    BYTE [di+DPT.bFlagsLow], FLGL_DPT_ASSISTED_LBA
-    jnz     SHORT .SkipInitializeDeviceParameters       ; No need to initialize CHS parameters if LBA mode enabled
-    call    AccessDPT_GetPointerToDRVPARAMStoCSBX
-    test    BYTE [cs:bx+DRVPARAMS.wFlags], FLG_DRVPARAMS_USERCHS    ; User specified P-CHS?
-    jz      SHORT .SkipInitializeDeviceParameters
-
     ; Initialize Logical Sectors per Track and Max Head number
-    mov     ax, [cs:bx+DRVPARAMS.wHeadsAndSectors]
+    mov     ax, [di+DPT.wPchsHeadsAndSectors]
     dec     ax                          ; Max Head number
-    xchg    al, ah                      ; Heads now in AH
-    mov     dx, ax                      ; Sectors per Track now in DL
+    xchg    ah, al
+    mov     dl, al                      ; Sectors per track
     mov     al, COMMAND_INITIALIZE_DEVICE_PARAMETERS
     mov     bx, TIMEOUT_AND_STATUS_TO_WAIT(TIMEOUT_BSY, FLG_STATUS_BSY)

trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h/EBIOS/AH48h_GetExtendedDriveParameters.asm

@@ -52 +52 @@
 ;    AH=48h Total Sector Count: 11873* 16*63 = 11,967,984
 ;
-; Notice how AH=48h returns lesser total sector count than AH=8h! The only
+; Notice how AH=48h returns lesser total sector count than AH=08h! The only
 ; way I could think of to get 11873 cylinders is to divide AH=08h sector
 ; count with P-CHS heads and sectors: (745*255*63) / (16*63) = 11873
 ;
-; I have no idea what is the reasoning behind it but at least there is one
-; BIOS that does just that.
-;
-; I decided that we multiply P-CHS values and do not waste space like the
-; Award BIOS does.
+; The only reason I can think of is that the Award BIOS has a bug and
+; uses L-CHS when it should use P-CHS values in the calculation.
 ;
 ;
@@ -139 +136 @@
     ; Store P-CHS. Based on phoenix specification this is returned only if
     ; total sector count is 15,482,880 or less.
-    sub     ax, 4001h
-    sbb     dx, 0ECh
+    sub     ax, MAX_SECTOR_COUNT_TO_RETURN_PCHS & 0FFFFh
+    sbb     dx, MAX_SECTOR_COUNT_TO_RETURN_PCHS >> 16
     sbb     bx, cx      ; Zero
-    jnc     SHORT .ReturnWithSuccess    ; More than EC4000h
-    or      WORD [di+EDRIVE_INFO.wFlags], FLG_CHS_INFORMATION_IS_VALID
+    ja      SHORT .ReturnWithSuccess
+    or      BYTE [di+EDRIVE_INFO.wFlags], FLG_CHS_INFORMATION_IS_VALID
 
     eMOVZX  dx, BYTE [es:si+DPT.bPchsHeads]

trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h/Tools/Address.asm

@@ -120 +120 @@
 ; Only 24-bits are used since LHCS to LBA28 conversion has 8.4GB limit.
 ; LBA = ((cylToSeek*headsPerCyl+headToSeek)*sectPerTrack)+sectToSeek-1
+; headsPerCyl and sectPerTrack are the current translation values (L-CHS).
 ;
 ; Returned address is in same registers that