Changeset 595 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/Handlers/Int19h/Int19hReset.asm

Timestamp:

Jul 7, 2018, 9:53:24 AM (7 years ago)

Author:

Tomi Tilli

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.

File:

• trunk/XTIDE_Universal_BIOS/Src/Handlers/Int19h/Int19hReset.asm (modified) (1 diff)

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