Changeset 148 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h.asm

Timestamp:

Mar 19, 2011, 8:09:41 PM (13 years ago)

Author:

aitotat

google:author:

aitotat

Message:

Changes to XTIDE Universal BIOS:

• INT 13h optimizations to save almost 100 bytes.

File:

• trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h.asm (modified) (3 diffs)

trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h.asm

@@ -4 +4 @@
 ; Section containing code
 SECTION .text
-
-;--------------------------------------------------------------------
-; Macro that prints drive and function number.
-; Used only for debugging.
-;
-; DEBUG_PRINT_DRIVE_AND_FUNCTION
-;   Parameters:
-;       AH:     INT 13h function number
-;       DL:     Drive number
-;   Returns:
-;       Nothing
-;   Corrupts registers:
-;       Nothing
-;--------------------------------------------------------------------
-%macro DEBUG_PRINT_DRIVE_AND_FUNCTION 0
-    push    dx
-    push    ax
-    mov     al, dl
-    call    Print_IntHexW
-    pop     ax
-    pop     dx
-%endmacro
-
 
 ;--------------------------------------------------------------------
@@ -32 +9 @@
 ; Jumps to specific function defined in AH.
 ;
-; Int13h_Jump
+; Note to developers: Do not make recursive INT 13h calls!
+;
+; Int13h_DiskFunctionsHandler
 ;   Parameters:
 ;       AH:     Bios function
 ;       DL:     Drive number
+;       Other:  Depends on function
+;   Returns:
+;       Depends on function
+;--------------------------------------------------------------------
+ALIGN JUMP_ALIGN
+Int13h_DiskFunctionsHandler:
+    sti                                 ; Enable interrupts
+    SAVE_AND_GET_INTPACK_TO_SSBP
+
+    call    RamVars_GetSegmentToDS
+    call    DriveXlate_ToOrBack
+    mov     [RAMVARS.xlateVars+XLATEVARS.bXlatedDrv], dl
+    call    RamVars_IsFunctionHandledByThisBIOS
+    jnc     SHORT Int13h_DirectCallToAnotherBios
+    call    FindDPT_ForDriveNumber      ; DS:DI now points to DPT
+
+    ; Jump to correct BIOS function
+JumpToBiosFunctionInAH:
+    cmp     ah, 25h                     ; Valid BIOS function?
+    ja      SHORT Int13h_UnsupportedFunction
+    eMOVZX  bx, ah
+    shl     bx, 1
+    jmp     [cs:bx+g_rgw13hFuncJump]    ; Jump to BIOS function
+
+
+;--------------------------------------------------------------------
+; Int13h_UnsupportedFunction
+; Int13h_DirectCallToAnotherBios
+;   Parameters:
+;       DL:     Translated drive number
+;       DS:     RAMVARS segment
+;       SS:BP:  Ptr to INTPACK
+;       BX, DI: Corrupted on Int13h_DiskFunctionsHandler
+;       Other:  Function specific INT 13h parameters 
 ;   Returns:
 ;       Depends on function
@@ -42 +55 @@
 ;--------------------------------------------------------------------
 ALIGN JUMP_ALIGN
-Int13h_DiskFunctions:
-    ; Save registers
-    sti                                 ; Enable interrupts
-    push    ds                          ; Store DS
-    push    di                          ; Store DI
-
-    ;DEBUG_PRINT_DRIVE_AND_FUNCTION
+Int13h_UnsupportedFunction:
+Int13h_DirectCallToAnotherBios:
+    call    ExchangeCurrentInt13hHandlerWithOldInt13hHandler
+    mov     bx, [bp+INTPACK.bx]
+    mov     di, [bp+INTPACK.di]
+    mov     ds, [bp+INTPACK.ds]
+    push    WORD [bp+INTPACK.flags]
+    popf
+    push    bp
+    mov     bp, [bp+INTPACK.bp]
+    int     BIOS_DISK_INTERRUPT_13h ; Can safely do as much recursion as it wants
+
+    ; Store returned values to INTPACK
+    pop     bp  ; Standard INT 13h functions never uses BP as return register
+%ifdef USE_386
+    mov     [bp+INTPACK.gs], gs
+    mov     [bp+INTPACK.fs], fs
+%endif
+    mov     [bp+INTPACK.es], es
+    mov     [bp+INTPACK.ds], ds
+    mov     [bp+INTPACK.di], di
+    mov     [bp+INTPACK.si], si
+    mov     [bp+INTPACK.bx], bx
+    mov     [bp+INTPACK.dh], dh
+    mov     [bp+INTPACK.cx], cx
+    mov     [bp+INTPACK.ax], ax
+    pushf
+    pop     WORD [bp+INTPACK.flags]
     call    RamVars_GetSegmentToDS
-    call    DriveXlate_WhenEnteringInt13h
-    call    RamVars_IsFunctionHandledByThisBIOS
-    jnc     SHORT Int13h_DirectCallToAnotherBios
-    ;DEBUG_PRINT_DRIVE_AND_FUNCTION
-
-    ; Jump to correct BIOS function
-    cmp     ah, 25h                     ; Valid BIOS function?
-    ja      SHORT Int13h_UnsupportedFunction
-    mov     di, ax
-%ifndef USE_186 ; This uses 9 bytes less and is about 5 cycles faster
-    mov     al, ah                      ; Copy bits in AH to AL and then
-    shl     al, 1                       ; shift them "back" 1 step
-    and     al, 7Eh                     ; AND them (clears the MSB)
-    cbw                                 ; Clear AH using sign extension
-    xchg    di, ax                      ; and finally swap DI with AX
-%else
-    eSHR_IM di, 7                       ; Shift function to DI...
-    and     di, BYTE 7Eh                ; ...and prepare for word lookup
-%endif
-    jmp     [cs:di+g_rgw13hFuncJump]    ; Jump to BIOS function
-
-
-;--------------------------------------------------------------------
-; Directs call to another INT13h function whose pointer is
-; stored to RAMVARS.
-;
-; Int13h_DirectCallToAnotherBios
-;   Parameters:
-;       AH:     Bios function
+    cmp     dl, [RAMVARS.xlateVars+XLATEVARS.bXlatedDrv]
+    je      SHORT .ExchangeInt13hHandlers
+    mov     [bp+INTPACK.dl], dl     ; Something is returned in DL
+ALIGN JUMP_ALIGN
+.ExchangeInt13hHandlers:
+    call    ExchangeCurrentInt13hHandlerWithOldInt13hHandler
+    ; Fall to Int13h_ReturnFromHandlerAfterStoringErrorCodeFromAH
+
+
+;--------------------------------------------------------------------
+; Int13h_ReturnFromHandlerAfterStoringErrorCodeFromAH
+; Int13h_ReturnFromHandlerWithoutStoringErrorCode
+;   Parameters:
+;       AH:     BIOS Error code
+;       SS:BP:  Ptr to INTPACK
+;   Returns:
+;       All registers are loaded from INTPACK
+;--------------------------------------------------------------------
+ALIGN JUMP_ALIGN
+Int13h_ReturnFromHandlerAfterStoringErrorCodeFromAH:
+    call    HError_SetErrorCodeToBdaAndToIntpackInSSBPfromAH
+Int13h_ReturnFromHandlerWithoutStoringErrorCode:
+    or      WORD [bp+INTPACK.flags], FLG_FLAGS_IF   ; Return with interrupts enabled
+    mov     sp, bp                                  ; Now we can exit anytime
+    RESTORE_INTPACK_FROM_SSBP
+
+
+;--------------------------------------------------------------------
+; Int13h_CallPreviousInt13hHandler
+;   Parameters:
+;       AH:     INT 13h function to call
 ;       DL:     Drive number
 ;       DS:     RAMVARS segment
-;       DI:     Corrupted
-;       Stack from top to down:
-;               Original DI
-;               Original DS
 ;   Returns:
 ;       Depends on function
 ;   Corrupts registers:
-;       Flags
-;--------------------------------------------------------------------
-ALIGN JUMP_ALIGN
-Int13h_UnsupportedFunction:
-Int13h_DirectCallToAnotherBios:
-    ; Temporarily store original DI and DS from stack to RAMVARS
-    pop     WORD [RAMVARS.wI13hDI]
-    pop     WORD [RAMVARS.wI13hDS]
-
-    ; Special return processing required if target function
-    ; returns something in DL
-    mov     di, Int13h_ReturnFromAnotherBiosWithValueInDL
-    call    DriveXlate_DoesFunctionReturnSomethingInDL
-    jc      SHORT .PushIretAddress
-    add     di, BYTE Int13h_ReturnFromAnotherBios - Int13h_ReturnFromAnotherBiosWithValueInDL
-.PushIretAddress:
-    pushf                               ; Push FLAGS to simulate INT
-    push    cs                          ; Push return segment
-    push    di                          ; Push return offset
-
-    ; "Return" to another INT 13h with original DI and DS
-    push    WORD [RAMVARS.fpOldI13h+2]  ; Segment
-    push    WORD [RAMVARS.fpOldI13h]    ; Offset
-    lds     di, [RAMVARS.dwI13DIDS]
-    cli                                 ; Disable interrupts as INT would
-    retf
-
-
-;--------------------------------------------------------------------
-; Int13h_CallPreviousInt13hHandler
-;   Parameters:
-;       AH:     Bios function
+;       BX, DI, ES
+;--------------------------------------------------------------------
+ALIGN JUMP_ALIGN
+Int13h_CallPreviousInt13hHandler:
+    push    di
+    call    ExchangeCurrentInt13hHandlerWithOldInt13hHandler
+    int     BIOS_DISK_INTERRUPT_13h
+    call    ExchangeCurrentInt13hHandlerWithOldInt13hHandler
+    pop     di
+    ret
+
+
+;--------------------------------------------------------------------
+; ExchangeCurrentInt13hHandlerWithOldInt13hHandler
+;   Parameters:
 ;       DS:     RAMVARS segment
-;       Other:  Depends on function to call
-;   Returns:
-;       Depends on function to call
+;   Returns:
+;       Nothing
 ;   Corrupts registers:
-;       Nothing
-;--------------------------------------------------------------------
-ALIGN JUMP_ALIGN
-Int13h_CallPreviousInt13hHandler:
-    pushf                               ; Push flags to simulate INT
-    cli                                 ; Disable interrupts since INT does that
-    call    FAR [RAMVARS.fpOldI13h]
-    sti
+;       DI
+;--------------------------------------------------------------------
+ALIGN JUMP_ALIGN
+ExchangeCurrentInt13hHandlerWithOldInt13hHandler:
+    push    es
+    LOAD_BDA_SEGMENT_TO es, di
+    mov     di, [RAMVARS.fpOldI13h]
+    xchg    di, [es:BIOS_DISK_INTERRUPT_13h*4]
+    mov     [RAMVARS.fpOldI13h], di
+    mov     di, [RAMVARS.fpOldI13h+2]
+    xchg    di, [es:BIOS_DISK_INTERRUPT_13h*4+2]
+    mov     [RAMVARS.fpOldI13h+2], di
+    pop     es
     ret
 
-
-;--------------------------------------------------------------------
-; Int13h_ReturnFromAnotherBiosWithValueInDL
-; Int13h_ReturnFromAnotherBios
-;   Parameters:
-;       AH:     Error code
-;       DL:     Drive number (only on Int13h_ReturnFromAnotherBios)
-;       CF:     Error status
-;   Returns:
-;       Depends on function
-;   Corrupts registers:
-;       Nothing (not even FLAGS)
-;--------------------------------------------------------------------
-ALIGN JUMP_ALIGN
-Int13h_ReturnFromAnotherBiosWithValueInDL:
-    push    ds
-    push    di
-    pushf                               ; Store return flags
-    call    RamVars_GetSegmentToDS
-    call    DriveXlate_WhenLeavingInt13hWithReturnValueInDL
-    jmp     SHORT Int13h_Leave
-
-ALIGN JUMP_ALIGN
-Int13h_ReturnFromAnotherBios:
-    push    ds
-    push    di
-    pushf                               ; Store return flags
-    call    RamVars_GetSegmentToDS
-    call    DriveXlate_WhenLeavingInt13h
-    jmp     SHORT Int13h_Leave
-
-
-;--------------------------------------------------------------------
-; Returns from any BIOS function implemented by this BIOS.
-;
-; Int13h_ReturnWithValueInDL
-; Int13h_PopXRegsAndReturn
-; Int13h_PopDiDsAndReturn
-;   Parameters:
-;       DL:     Drive number (not Int13h_ReturnWithoutSwappingDrives)
-;       DS:     RAMVARS segment
-;   Returns:
-;       Depends on function
-;   Corrupts registers:
-;       Nothing (not even FLAGS)
-;--------------------------------------------------------------------
-ALIGN JUMP_ALIGN
-Int13h_ReturnWithValueInDL:
-    pushf
-    call    DriveXlate_WhenLeavingInt13hWithReturnValueInDL
-    jmp     SHORT Int13h_LeaveAfterStoringErrorCodeToBDA
-
-ALIGN JUMP_ALIGN
-Int13h_PopXRegsAndReturn:
-    pop     bx                          ; Pop old AX to BX
-    mov     al, bl                      ; Restore AL
-    pop     bx
-    pop     cx
-    pop     dx
-    ; Fall to Int13h_PopDiDsAndReturn
-
-ALIGN JUMP_ALIGN
-Int13h_PopDiDsAndReturn:
-    pushf
-    call    DriveXlate_WhenLeavingInt13h
-    ; Fall to Int13h_LeaveAfterStoringErrorCodeToBDA
-
-Int13h_LeaveAfterStoringErrorCodeToBDA:
-    LOAD_BDA_SEGMENT_TO ds, di
-    mov     [BDA.bHDStatus], ah
-    ; Fall to Int13h_Leave
-
-Int13h_Leave:
-    popf
-    pop     di
-    pop     ds
-    retf    2