source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Device/IDE/IdeIrq.asm

; Project name  :   XTIDE Universal BIOS
; Description   :   Interrupt handling related functions.

;
; XTIDE Universal BIOS and Associated Tools
; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team.
;
; This program is free software; you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation; either version 2 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
; GNU General Public License for more details.
; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
;

; Section containing code
SECTION .text

;--------------------------------------------------------------------
; IdeIrq_WaitForIRQ
;   Parameters:
;       DS:DI:  Ptr to DPT (in RAMVARS segment)
;   Returns:
;       Nothing
;   Corrupts registers:
;       AX
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
IdeIrq_WaitForIRQ:
    push    ds
    LOAD_BDA_SEGMENT_TO ds, ax, !       ; Zero AX
    mov     ah, OS_HOOK_DEVICE_BUSY     ; Hard disk busy (AX=9000h)
    cli                                 ; Disable interrupts
    dec     BYTE [BDA.bHDTaskFlg]       ; Clear to zero if still waiting for IRQ
    pop     ds
    jnz     SHORT .ReturnFromWaitNotify ; IRQ already! (CompactFlash was faster than CPU)   
    int     BIOS_SYSTEM_INTERRUPT_15h   ; OS hook, device busy

.ReturnFromWaitNotify:
    sti                                 ; Enable interrupts
    ret


;--------------------------------------------------------------------
; IDE Interrupt Service Routines.
;
; IdeIrq_InterruptServiceRoutineForIrqs2to7
; IdeIrq_InterruptServiceRoutineForIrqs8to15
;   Parameters:
;       Nothing
;   Returns:
;       Nothing
;   Corrupts registers:
;       Nothing
;--------------------------------------------------------------------
ALIGN JUMP_ALIGN
IdeIrq_InterruptServiceRoutineForIrqs2to7:
    push    ax
    mov     al, COMMAND_END_OF_INTERRUPT

%ifdef USE_AT
    jmp     SHORT AcknowledgeMasterInterruptController

ALIGN JUMP_ALIGN
IdeIrq_InterruptServiceRoutineForIrqs8to15:
    push    ax
    mov     al, COMMAND_END_OF_INTERRUPT
    out     SLAVE_8259_COMMAND_out, al  ; Acknowledge Slave 8259
    JMP_DELAY
AcknowledgeMasterInterruptController:
%endif ; USE_AT

    out     MASTER_8259_COMMAND_out, al ; Acknowledge Master 8259

    ; Set Task Flag
    push    ds
    LOAD_BDA_SEGMENT_TO ds, ax, !       ; Clear AL and CF for INT 15h
    dec     BYTE [BDA.bHDTaskFlg]       ; Set task flag (or clear if IRQ occurred before call to INT 15h AH=90h)
    sti                                 ; Enable interrupts
    pop     ds

    ; Issue Int 15h, function AX=9100h (Interrupt ready)
    jz      SHORT .DoNotPostSinceIrqOccurredBeforeWait
    mov     ah, OS_HOOK_DEVICE_POST     ; Interrupt ready, device 0 (HD)
    int     BIOS_SYSTEM_INTERRUPT_15h
.DoNotPostSinceIrqOccurredBeforeWait:

    pop     ax
    iret