Changeset 557 in xtideuniversalbios

Timestamp:

Jun 19, 2013, 6:47:58 PM (11 years ago)

Author:

aitotat@…

google:author:

aitotat@gmail.com

Message:

Changes to XTIDE Universal BIOS:

• Finally fixed the Windows 98 problem (blue sceen when loading hsflop.pdr). Windows didn't like INT 13 handler being changed.

File:

• trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h.asm (modified) (4 diffs)

trunk/XTIDE_Universal_BIOS/Src/Handlers/Int13h.asm

@@ -103 +103 @@
 %ifdef MODULE_DRIVEXLATE
     call    DriveXlate_ToOrBack
-    mov     [RAMVARS.xlateVars+XLATEVARS.bXlatedDrv], dl
 %endif
     call    FindDPT_ForDriveNumberInDL  ; DS:DI points to our DPT, or NULL if not our drive
@@ -166 +165 @@
 UnsupportedFunction:
 Int13h_DirectCallToAnotherBios:
-    call    ExchangeCurrentInt13hHandlerWithOldInt13hHandler
+%ifdef MODULE_DRIVEXLATE
+    ; Disable drive number translations in case of recursive INT 13h calls
+    mov     [RAMVARS.xlateVars+XLATEVARS.bXlatedDrv], dl
+    push    WORD [RAMVARS.xlateVars+XLATEVARS.wFDandHDswap]
+    mov     WORD [RAMVARS.xlateVars+XLATEVARS.wFDandHDswap], 8000h  ; No translation
+%endif
+
+    push    bp                          ; Store offset to IDEPACK (SS:SP now points it)
+
+    ; Simulate INT by pushing flags and return address
+    push    WORD [bp+IDEPACK.intpack+INTPACK.flags]
+    popf
+    pushf                               ; Simulate INT by pushing flags
+    push    cs
+    ePUSH_T di, .ReturnFromAnotherBios  ; Can not corrupt flags
+
+    ; Push old INT 13h handler and restore registers
+    push    WORD [RAMVARS.fpOldI13h+2]
+    push    WORD [RAMVARS.fpOldI13h]
     mov     bx, [bp+IDEPACK.intpack+INTPACK.bx]
     mov     di, [bp+IDEPACK.intpack+INTPACK.di]
     mov     ds, [bp+IDEPACK.intpack+INTPACK.ds]
-    push    WORD [bp+IDEPACK.intpack+INTPACK.flags]
-    popf
-    push    bp
     mov     bp, [bp+IDEPACK.intpack+INTPACK.bp]
-
-    test    dl, dl
-    js      SHORT .CallHardDiskHandler
-    int     BIOS_DISKETTE_INTERRUPT_40h ; Windows 98 requires we call INT 40h for floppy drives (reason unknown)
-    SKIP2B  bp                          ; Skip INT 13h
-.CallHardDiskHandler:
-    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
+    retf                                ; "Return" to old INT 13h
+.ReturnFromAnotherBios:
+
+%if 0
+    ; We need to restore our pointer to IDEPACK but we cannot corrupt any register
+    push    ax                          ; Dummy WORD
+    cli
+    xchg    bp, sp
+    mov     [bp], sp                    ; Replace dummy WORD with returned BP
+    mov     sp, [bp+2]                  ; Load offset to IDEPACK
+    xchg    sp, bp
+    sti                                 ; We would have set IF anyway when exiting INT 13h
+    pop     WORD [bp+IDEPACK.intpack+INTPACK.bp]
+%endif
+    ; Actually we can corrupt BP since no standard INT 13h function uses it as return
+    ; register. Above code is kept here just in case if there is some non-standard function.
+    ; POP BP below also belongs to the above code.
+    pop     bp                          ; Clean IDEPACK offset from stack
+
+    ; Store remaining returned values to INTPACK
 %ifdef USE_386
+; We do not use GS or FS at the moment
 ;   mov     [bp+IDEPACK.intpack+INTPACK.gs], gs
 ;   mov     [bp+IDEPACK.intpack+INTPACK.fs], fs
@@ -205 +230 @@
 
 %ifdef MODULE_DRIVEXLATE
+    ; Restore drive number translation back to what it was
+    pop     WORD [RAMVARS.xlateVars+XLATEVARS.wFDandHDswap]
     cmp     dl, [RAMVARS.xlateVars+XLATEVARS.bXlatedDrv]    ; DL is still drive number?
-    je      SHORT .ExchangeInt13hHandlers
+    je      SHORT Int13h_ReturnFromHandlerAfterStoringErrorCodeFromAH
     mov     [bp+IDEPACK.intpack+INTPACK.dl], dl ; Something is returned in DL
-ALIGN JUMP_ALIGN
-.ExchangeInt13hHandlers:
-%endif
-
-%ifdef USE_186
-    push    Int13h_ReturnFromHandlerAfterStoringErrorCodeFromAH
-    jmp     SHORT ExchangeCurrentInt13hHandlerWithOldInt13hHandler
-%else
-    call    ExchangeCurrentInt13hHandlerWithOldInt13hHandler
+%endif
     jmp     SHORT Int13h_ReturnFromHandlerAfterStoringErrorCodeFromAH
-%endif
 
 
@@ -295 +313 @@
 ALIGN JUMP_ALIGN
 Int13h_CallPreviousInt13hHandler:
-    call    ExchangeCurrentInt13hHandlerWithOldInt13hHandler
-    int     BIOS_DISK_INTERRUPT_13h
-;;;  fall-through to ExchangeCurrentInt13hHandlerWithOldInt13hHandler
-
-;--------------------------------------------------------------------
-; ExchangeCurrentInt13hHandlerWithOldInt13hHandler
-;   Parameters:
-;       DS:     RAMVARS segment
-;   Returns:
-;       Nothing
-;   Corrupts registers:
-;       Nothing
-;       Note: Flags are preserved
-;--------------------------------------------------------------------
-ALIGN JUMP_ALIGN
-ExchangeCurrentInt13hHandlerWithOldInt13hHandler:
-    push    es
-    push    si
-    LOAD_BDA_SEGMENT_PRESERVE_FLAGS_TO  es, si
-    mov     si, [RAMVARS.fpOldI13h]
-    cli
-    xchg    si, [es:BIOS_DISK_INTERRUPT_13h*4]
-    mov     [RAMVARS.fpOldI13h], si
-    mov     si, [RAMVARS.fpOldI13h+2]
-    xchg    si, [es:BIOS_DISK_INTERRUPT_13h*4+2]
-    sti
-    mov     [RAMVARS.fpOldI13h+2], si
-    pop     si
-    pop     es
+    pushf                       ; Simulate INT by pushing flags
+    call far [RAMVARS.fpOldI13h]
     ret