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;;                                                                          ;;
;; This file is part of 'M', a MIPS system emulator.                        ;;
;;                                                                          ;;
;; (C) 2019 Stanislav Datskovskiy ( www.loper-os.org )                      ;;
;; http://wot.deedbot.org/17215D118B7239507FAFED98B98228A001ABFFC7.html     ;;
;;                                                                          ;;
;; You do not have, nor can you ever acquire the right to use, copy or      ;;
;; distribute this software ; Should you use this software for any purpose, ;;
;; or copy and distribute it to anyone or in any manner, you are breaking   ;;
;; the laws of whatever soi-disant jurisdiction, and you promise to         ;;
;; continue doing so for the indefinite future. In any case, please         ;;
;; always : read and understand any software ; verify any PGP signatures    ;;
;; that you use - for any purpose.                                          ;;
;;                                                                          ;;
;; See also http://trilema.com/2015/a-new-software-licensing-paradigm .     ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;-----------------------------------------------------------------------------
;; State
;-----------------------------------------------------------------------------
section .bss
        SlaveIRQ        resd 1 ; External Interrupt from Slaves
;-----------------------------------------------------------------------------

section .text

;-----------------------------------------------------------------------------
; SetIRQ : Trigger External Interrupt ( Parameter: constant IRQ # )
;-----------------------------------------------------------------------------
%macro SetIRQ   1  ; param is the IRQ #
        bts     CP0_Cause, (CP0Cau_IRQ_Bottom + %1)
%endmacro
;-----------------------------------------------------------------------------

;-----------------------------------------------------------------------------
; ClrIRQ : Clear External Interrupt ( Parameter: constant IRQ # )
;-----------------------------------------------------------------------------
%macro ClrIRQ   1  ; param is the IRQ #
        btr     CP0_Cause, (CP0Cau_IRQ_Bottom + %1)
%endmacro
;-----------------------------------------------------------------------------

;-----------------------------------------------------------------------------
; Built-In Iron IRQs:
;-----------------------------------------------------------------------------
%define TIMER_IRQ   7 ; MIPS Timer (trigger when CP0_Count==CP0_Compare)
;-----------------------------------------------------------------------------

;-----------------------------------------------------------------------------
; IRQ from Slave:
;; TODO: locking and wait/sleep
;-----------------------------------------------------------------------------
%macro SetSlaveIRQ  1
        bts     dword [SlaveIRQ], (CP0Cau_IRQ_Bottom + %1)
%endmacro
;-----------------------------------------------------------------------------

;-----------------------------------------------------------------------------
; Poll for any Slave IRQ:
;-----------------------------------------------------------------------------
%macro GetSlaveIRQ  0
        mov     eax, [SlaveIRQ]      ; Get the Slave IRQ shadow register
        test    eax, eax             ; Is it zero?
        jz      %%skip               ; If was zero, skip;
        mov     dword [SlaveIRQ], 0  ; Else, 1) Zero shadow register
        or      CP0_Cause, eax       ;       2) OR it into CP0_Cause.
%%skip:
%endmacro
;-----------------------------------------------------------------------------