Changeset 595 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/Handlers/Int19h

Timestamp:

Jul 7, 2018, 9:53:24 AM (6 years ago)

Author:

aitotat

Message:

• Int 19h reset handler now tries to boot from drive A before warm reset. This should help to get INT 10h hooked before launching booter games (meaning system reset without reseting interrupt vector table).
• Win 95 hack temporarily removed (module not included by default). Very limited testing shows that CMOS hack seems to work with AMI bios but locks on Award BIOS.

Location:

trunk/XTIDE_Universal_BIOS/Src/Handlers/Int19h

Files:

• BootSector.asm (modified) (4 diffs)
• Int19hReset.asm (modified) (1 diff)

trunk/XTIDE_Universal_BIOS/Src/Handlers/Int19h/BootSector.asm

@@ -35 +35 @@
 BootSector_TryToLoadFromDriveDL_AndBoot:
     call    DetectPrint_TryToBootFromDL
-    call    LoadFirstSectorFromDriveDL
+    call    BootSector_LoadFirstSectorFromDriveDL
     jnc     SHORT .FirstSectorLoadedToESBX
 
@@ -60 +60 @@
 .AlwaysBootFromFloppyDriveForBooterGames:
     stc     ; Boot Sector loaded successfully
-    jmp     SHORT Int19_JumpToBootSectorOrRomBoot
+    jmp     SHORT Int19h_JumpToBootSectorOrRomBoot
 
 .FirstHardDiskSectorNotBootable:
@@ -71 +71 @@
 
 ;--------------------------------------------------------------------
-; LoadFirstSectorFromDriveDL
+; BootSector_LoadFirstSectorFromDriveDL
 ;   Parameters:
 ;       DL:     Drive to boot from (translated, 00h or 80h)
@@ -82 +82 @@
 ;       AL, CX, DH, DI
 ;--------------------------------------------------------------------
-LoadFirstSectorFromDriveDL:
+BootSector_LoadFirstSectorFromDriveDL:
     LOAD_BDA_SEGMENT_TO es, bx              ; ES:BX now points to...
     mov     bx, BOOTVARS.rgbBootSect        ; ...boot sector location

trunk/XTIDE_Universal_BIOS/Src/Handlers/Int19h/Int19hReset.asm

@@ -32 +32 @@
 ;--------------------------------------------------------------------
 Int19hReset_Handler:
+    ; Try to boot from drive A.
+    ; This is needed if INT 19h is used to launch booter games while
+    ; preserving interrupt vector table (for example to hook interrupt 10h)
+    xor     dx, dx      ; Drive 00h
+    call    BootSector_LoadFirstSectorFromDriveDL
+    jc      SHORT .Reboot
+
+    xor     ax, ax
+    mov     ds, ax
+%ifdef USE_386
+    mov     fs, ax
+    mov     gs, ax
+%endif
+    cmp     WORD [bx+510], 0AA55h   ; Valid boot sector?
+    jne     SHORT .Reboot
+    push    es                      ; Zero
+    push    bx
+    retf
+
+    ; Do warm reset since boot from floppy drive failed
+.Reboot:
     mov     ax, BOOT_FLAG_WARM              ; Skip memory tests
     jmp     Reboot_ComputerWithBootFlagInAX