Changeset 150 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/AccessDPT.asm

Timestamp:

Apr 29, 2011, 7:04:13 PM (13 years ago)

Author:

aitotat

google:author:

aitotat

Message:

Changes to XTIDE Universal BIOS:

• Redesigned Disk Parameter Tables.
• Code generalizations for supporting non-IDE devices in the future.

File:

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

trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/AccessDPT.asm

@@ -6 +6 @@
 
 ;--------------------------------------------------------------------
-; Returns L-CHS values from DPT.
-;
+; AccessDPT_GetDriveSelectByteToAL
+;   Parameters:
+;       DS:DI:  Ptr to Disk Parameter Table
+;   Returns:
+;       AL:     Drive Select Byte
+;   Corrupts registers:
+;       Nothing
+;--------------------------------------------------------------------
+ALIGN JUMP_ALIGN
+AccessDPT_GetDriveSelectByteToAL:
+    mov     al, [di+DPT.wFlags]
+    and     al, FLG_DRVNHEAD_LBA | FLG_DRVNHEAD_DRV
+    or      al, MASK_DRVNHEAD_SET   ; Bits set to 1 for old drives
+    ret
+
+
+;--------------------------------------------------------------------
+; AccessDPT_GetDeviceControlByteToAL
+;   Parameters:
+;       DS:DI:  Ptr to Disk Parameter Table
+;   Returns:
+;       AL:     Device Control Byte
+;   Corrupts registers:
+;       Nothing
+;--------------------------------------------------------------------
+ALIGN JUMP_ALIGN
+AccessDPT_GetDeviceControlByteToAL:
+    xor     al, al
+    test    BYTE [di+DPT.wFlags], FLG_DPT_ENABLE_IRQ
+    jnz     SHORT .EnableDeviceIrq
+    or      al, FLG_DEVCONTROL_nIEN ; Disable IRQ
+.EnableDeviceIrq:
+    ret
+
+
+;--------------------------------------------------------------------
+; AccessDPT_GetAddressingModeForWordLookToBX
+;   Parameters:
+;       DS:DI:  Ptr to Disk Parameter Table
+;   Returns:
+;       BX:     Addressing Mode (L-CHS, P-CHS, LBA28, LBA48) shifted for WORD lookup
+;   Corrupts registers:
+;       Nothing
+;--------------------------------------------------------------------
+ALIGN JUMP_ALIGN
+AccessDPT_GetAddressingModeForWordLookToBX:
+    mov     bl, [di+DPT.wFlags]
+    and     bx, BYTE MASK_DPT_ADDRESSING_MODE
+    eSHR_IM bx, ADDRESSING_MODE_FIELD_POSITION-1
+    ret
+
+
+;--------------------------------------------------------------------
 ; AccessDPT_GetLCHSfromPCHS
 ;   Parameters:
@@ -21 +72 @@
 AccessDPT_GetLCHSfromPCHS:
     xchg    ax, cx
-    mov     cl, [di+DPT.bShLtoP]        ; Load shift count
-    mov     bx, [di+DPT.wPCyls]         ; Load P-CHS cylinders
-    shr     bx, cl                      ; Shift to L-CHS cylinders
+    mov     cl, [di+DPT.wFlags]
+    and     cl, MASK_DPT_CHS_SHIFT_COUNT    ; Load shift count
+    mov     bx, [di+DPT.wPchsCylinders]     ; Load P-CHS cylinders
+    shr     bx, cl                          ; Shift to L-CHS cylinders
     xchg    cx, ax
-    mov     dx, [di+DPT.wLHeads]        ; Load L-CHS heads
-    eMOVZX  ax, BYTE [di+DPT.bPSect]    ; Load Sectors per track
+    eMOVZX  dx, BYTE [di+DPT.bLchsHeads]    ; Load L-CHS heads
+    eMOVZX  ax, BYTE [di+DPT.bPchsSectors]  ; Load Sectors per track
     ret
 
 
 ;--------------------------------------------------------------------
-; Tests IDEVARS flags for master or slave drive.
-;
 ; AccessDPT_TestIdeVarsFlagsForMasterOrSlaveDrive
 ;   Parameters:
@@ -63 +113 @@
 ALIGN JUMP_ALIGN
 AccessDPT_GetPointerToDRVPARAMStoCSBX:
-    eMOVZX  bx, [di+DPT.bIdeOff]        ; CS:BX points to IDEVARS
-    test    BYTE [di+DPT.bDrvSel], FLG_IDE_DRVHD_DRV
-    jnz     SHORT .ReturnPointerToSlaveDRVPARAMS
-    add     bx, BYTE IDEVARS.drvParamsMaster
+    eMOVZX  bx, [di+DPT.bIdevarsOffset]         ; CS:BX points to IDEVARS
+    add     bx, BYTE IDEVARS.drvParamsMaster    ; CS:BX points to Master Drive DRVPARAMS
+    test    BYTE [di+DPT.wFlags], FLG_DPT_SLAVE
+    jz      SHORT .ReturnPointerToDRVPARAMS
+    add     bx, BYTE DRVPARAMS_size             ; CS:BX points to Slave Drive DRVPARAMS
+.ReturnPointerToDRVPARAMS:
     ret
-ALIGN JUMP_ALIGN
-.ReturnPointerToSlaveDRVPARAMS:
-    add     bx, BYTE IDEVARS.drvParamsSlave
-    ret