Changeset 262 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/RamVars.asm

Timestamp:

Feb 24, 2012, 10:28:31 AM (12 years ago)

Author:

gregli@…

google:author:

gregli@hotmail.com

Message:

More optimizations. Merged RamVars_IsFunction/DriveHandledByThisBIOS in with FindDPT_ForDriveNumber, since they are often used together, making a returned NULL DI pointer indicate a foreign drive in many places. Revamped the iteration done in the handlers for int13/0dh and int13h/0h. Added serial specific print string during drive detection.

File:

• trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/RamVars.asm (modified) (1 diff)

trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/RamVars.asm

@@ -115 +115 @@
 
 ;--------------------------------------------------------------------
-; Checks if INT 13h function is handled by this BIOS.
-;
-; RamVars_IsFunctionHandledByThisBIOS
-;   Parameters:
-;       AH:     INT 13h function number
-;       DL:     Drive number
-;       DS:     RAMVARS segment
-;   Returns:
-;       CF:     Cleared if function is handled by this BIOS
-;               Set if function belongs to some other BIOS
-;   Corrupts registers:
-;       Nothing
-;--------------------------------------------------------------------
-ALIGN JUMP_ALIGN
-RamVars_IsFunctionHandledByThisBIOS:
-    test    ah, ah          ; Reset for all floppy and hard disk drives?
-    jz      SHORT RamVars_IsDriveHandledByThisBIOS.CFAlreadyClear_IsHandledByOurBIOS
-    cmp     ah, 08h
-%ifdef MODULE_SERIAL_FLOPPY
-; we handle all traffic for function 08h, as we need to wrap both hard disk and floppy drive counts
-    je      SHORT RamVars_IsDriveHandledByThisBIOS.CFAlreadyClear_IsHandledByOurBIOS
-%else
-; we handle all *hard disk* traffic for function 08h, as we need to wrap the hard disk drive count
-    je      SHORT RamVars_IsDriveHandledByThisBIOS.IsDriveAHardDisk
-%endif
-;;; fall-through            
-        
-;--------------------------------------------------------------------
-; Checks if drive is handled by this BIOS.
-;
-; RamVars_IsDriveHandledByThisBIOS
-;   Parameters:
-;       DL:     Drive number
-;       DS:     RAMVARS segment
-;   Returns:
-;       CF:     Cleared if drive is handled by this BIOS
-;               Set if drive belongs to some other BIOS
-;   Corrupts registers:
-;       Nothing
-;--------------------------------------------------------------------
-ALIGN JUMP_ALIGN
-RamVars_IsDriveHandledByThisBIOS:
-    push    ax
-
-    mov     ax, [RAMVARS.wDrvCntAndFirst]       ; Drive count to AH, First number to AL
-    add     ah, al                              ; One past last drive to AH
-    cmp     dl, ah                              ; Above last supported?
-    jae     SHORT .HardDiskIsNotHandledByThisBIOS
-.TestLowLimit:
-    cmp     dl, al                              ; Below first supported?
-    jae     SHORT .CFAlreadyClear_IsHandledByOurBIOS_PopAX  ; note that CF is clear if the branch is taken
-
-.HardDiskIsNotHandledByThisBIOS:
-%ifdef MODULE_SERIAL_FLOPPY
-    call    RamVars_UnpackFlopCntAndFirstToAL
-    cbw                                         ; normally 0h, could be ffh if no drives present
-    adc     ah, al                              ; if no drives present, still ffh (ffh + ffh + 1 = ffh)
-    js      SHORT .DiskIsNotHandledByThisBIOS
-    cmp     ah, dl
-    jz      SHORT .CFAlreadyClear_IsHandledByOurBIOS_PopAX
-    cmp     al, dl
-    jz      SHORT .CFAlreadyClear_IsHandledByOurBIOS_PopAX
-.DiskIsNotHandledByThisBIOS:            
-%endif
-
-    stc                                         ; Is not supported by our BIOS
-        
-.CFAlreadyClear_IsHandledByOurBIOS_PopAX:               
-    pop     ax
-.CFAlreadyClear_IsHandledByOurBIOS: 
-    ret
-
-%ifndef MODULE_SERIAL_FLOPPY        
-;
-; Note that we could have just checked for the high order bit in dl, but with the needed STC and jumps, 
-; leveraging the code above resulted in space savings.
-;
-.IsDriveAHardDisk:      
-    push    ax                                  ; match stack at the top of routine
-    mov     al, 80h                             ; to catch all hard disks, lower limit is 80h vs. bFirstDrv
-    jmp     .TestLowLimit                       ; and there is no need to test a high limit
-%endif
-
-;--------------------------------------------------------------------
 ; RamVars_GetHardDiskCountFromBDAtoAX
 ;   Parameters: