User:Johnburger/Demo/Exec/Ints/Double

There are two aspects of the Double Fault handler: the installer, and the handler itself. The generic routines have been written, it's just a matter of calling them.

Note that when a Task does an IRET, it picks up again from the next instruction! I don't know about you, but it looks weird to me...

Demo/Exec/Ints/Double.inc

;
; Exec/Ints/Double.inc
;
 
; Ths module installs a Double Fault handler. It's mostly a stub, leaving the
; hard work to the generic .Fault handler.
Exec.Ints.Double:
                MOV             EAX,IDT.Double  ; This is the IDT Entry
                MOV             EBX,Exec.LDT.Double ; This is the LDT triple
                MOV             EDX,.Handler    ; This is the handler
                CALL            Exec.Ints.Fault ; Set it up
                RET
.Handler:
;               PUSH   DWORD    0               ; Pseudo-fault code (not required)
                PUSH            8               ; Interrupt number
                MOV             EBX,Exec.LDT.Double.TSS ; For TSS Backlink
                CALL            Exec.Ints.Fault.Handler
                ADD             ESP,8           ; Get rid of above
                IRETD                           ; Return, but resumes here, so...
                JMP             .Handler        ; ...go back for more