Changeset 32 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/RamVars.asm

Timestamp:

Aug 6, 2010, 7:11:04 AM (14 years ago)

Author:

aitotat

google:author:

aitotat

Message:

Correct number of drives is now returned from AH=08h even when it is redirected to foreign BIOS.

File:

• trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/RamVars.asm (modified) (3 diffs)

trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/RamVars.asm

@@ -2 +2 @@
 ; Project name  :   IDE BIOS
 ; Created date  :   14.3.2010
-; Last update   :   2.5.2010
+; Last update   :   3.8.2010
 ; Author        :   Tomi Tilli
 ; Description   :   Functions for accessings RAMVARS.
@@ -130 +130 @@
 RamVars_IsFunctionHandledByThisBIOS:
     test    ah, ah          ; Reset for all floppy and hard disk drives?
-    jnz     SHORT RamVars_IsDriveHandledByThisBIOS
+    jz      SHORT .FunctionIsHandledByOurBIOS
+    cmp     ah, 08h         ; Read Disk Drive Parameters?
+    jne     SHORT RamVars_IsDriveHandledByThisBIOS
+    test    dl, 80h         ; We dot not handle floppy drives
+    jz      SHORT .FunctionIsNotHandledByOurBIOS
+ALIGN JUMP_ALIGN
+.FunctionIsHandledByOurBIOS:
     stc
+.FunctionIsNotHandledByOurBIOS:
     ret
 
@@ -190 +197 @@
 
 ;--------------------------------------------------------------------
-; Return number of Hard Disks in system.
-;
-; RamVars_GetDriveCounts
-;   Parameters:
-;       DS:     RAMVARS segment
-;   Returns:
-;       AL:     Number of hard disks handled by our BIOS
-;       CX:     Total number of hard disks in system
-;   Corrupts registers:
-;       AH
-;--------------------------------------------------------------------
-ALIGN JUMP_ALIGN
-RamVars_GetDriveCounts:
+; RamVars_GetHardDiskCountFromBDAtoCX
+;   Parameters:
+;       DS:     RAMVARS segment
+;   Returns:
+;       CX:     Total hard disk count
+;   Corrupts registers:
+;       Nothing
+;--------------------------------------------------------------------   
+ALIGN JUMP_ALIGN
+RamVars_GetHardDiskCountFromBDAtoCX:
     push    es
+    push    dx
+
     LOAD_BDA_SEGMENT_TO es, cx          ; Zero CX
-    mov     cl, [es:BDA.bHDCount]       ; Total hard drive count
-    mov     al, [RAMVARS.bDrvCnt]       ; Our drive count
+    call    RamVars_GetCountOfKnownDrivesToDL
+    MAX_U   dl, [es:BDA.bHDCount]
+    mov     cl, dl
+
+    pop     dx
     pop     es
     ret
+
+;--------------------------------------------------------------------
+; RamVars_GetCountOfKnownDrivesToDL
+;   Parameters:
+;       DS:     RAMVARS segment
+;   Returns:
+;       DL:     Total hard disk count
+;   Corrupts registers:
+;       Nothing
+;--------------------------------------------------------------------   
+ALIGN JUMP_ALIGN
+RamVars_GetCountOfKnownDrivesToDL:
+    mov     dl, [RAMVARS.bFirstDrv]     ; Number for our first drive
+    add     dl, [RAMVARS.bDrvCnt]       ; Our drives
+    and     dl, 7Fh                     ; Clear HD bit for drive count
+    ret