IFND    EXEC_ABLES_I
EXEC_ABLES_I    SET     1
**
**      $Filename: exec/ables.i $
**      $Release: 2.04 Includes, V37.4 $
**      $Revision: 36.6 $
**      $Date: 90/05/10 $
**
**      Task switch and interrupt control macros
**
**      (C) Copyright 1985-1999 Amiga, Inc.
**          All Rights Reserved
**

    IFND EXEC_TYPES_I
    INCLUDE "exec/types.i"
    ENDC        ; EXEC_TYPES_I

    IFND EXEC_EXECBASE_I
    INCLUDE "exec/execbase.i"
    ENDC        ; EXEC_EXECBASE_I


*-------------------------------------------------------------------------
*
*   Interrupt Exclusion Macros.  Disable all tasks and interrupts.
*
*-------------------------------------------------------------------------

INT_ABLES   MACRO               ; externals used by DISABLE and ENABLE
            XREF    _intena
            ENDM

;Disable interrupts.  Avoid use of DISABLE if at all possible.
;Please realize the danger of this macro!  Don't disable for long periods!
DISABLE     MACRO   ; [scratchReg],[NOFETCH] or have ExecBase in A6.
            IFC     '\1',''             ;Case 1: Assume A6=ExecBase
              MOVE.W  #$04000,_intena   ;(NOT IF_SETCLR)+IF_INTEN
              ADDQ.B  #1,IDNestCnt(A6)
              MEXIT
            ENDC
            IFC     '\2','NOFETCH'      ;Case 2: Assume \1=ExecBase
              MOVE.W  #$04000,_intena
              ADDQ.B  #1,IDNestCnt(\1)
              MEXIT
            ENDC
            IFNC    '\1',''             ;Case 3: Use \1 as scratch
              MOVE.L  4,\1              ;Get ExecBase
              MOVE.W  #$04000,_intena
              ADDQ.B  #1,IDNestCnt(\1)
              MEXIT
            ENDC
            ENDM

;Enable interrupts.  Please realize the danger of this macro!
ENABLE      MACRO   ; [scratchReg],[NOFETCH] or have ExecBase in A6.
            IFC     '\1',''             ;Case 1: Assume A6=ExecBase
              SUBQ.B  #1,IDNestCnt(A6)
              BGE.S   ENABLE\@
              MOVE.W  #$0C000,_intena   ;IF_SETCLR+IF_INTEN
ENABLE\@:
              MEXIT
            ENDC
            IFC     '\2','NOFETCH'      ;Case 2: Assume \1=ExecBase
              SUBQ.B  #1,IDNestCnt(\1)
              BGE.S   ENABLE\@
              MOVE.W  #$0C000,_intena
ENABLE\@:
              MEXIT
            ENDC
            IFNC    '\1',''             ;Case 3: Use \1 as scratch
              MOVE.L  4,\1              ;Get ExecBase
              SUBQ.B  #1,IDNestCnt(\1)
              BGE.S   ENABLE\@
              MOVE.W  #$0C000,_intena
ENABLE\@:
              MEXIT
            ENDC
            ENDM


*-------------------------------------------------------------------------
*
*   Tasking Exclusion Macros.  Forbid all other tasks (but not interrupts)
*
*-------------------------------------------------------------------------

TASK_ABLES  MACRO               ; externals used by FORBID and PERMIT
            XREF    _LVOPermit
            ENDM

;Prevent task switching (disables reschedule)
FORBID      MACRO   ; [scratchReg],[NOFETCH] or ExecBase in A6!
            IFC     '\1',''             ;Case 1: Assume A6=ExecBase
              ADDQ.B  #1,TDNestCnt(A6)
              MEXIT
            ENDC
            IFC     '\2','NOFETCH'      ;Case 2: Assume \1=ExecBase
              ADDQ.B  #1,TDNestCnt(\1)
              MEXIT
            ENDC
            IFNC    '\1',''             ;Case 3: Use \1 as scratch
              MOVE.L  4,\1      ;Get ExecBase
              ADDQ.B  #1,TDNestCnt(\1)
              MEXIT
            ENDC
            ENDM

;Enable task switching
PERMIT      MACRO   ; [saveFlag],[NOFETCH] or ExecBase in A6!
            IFC     '\1',''             ;Case 1: Assume A6=ExecBase
              JSR     _LVOPermit(A6)
              MEXIT
            ENDC
            IFC     '\2','NOFETCH'      ;Case 2: Assume \1=ExecBase
              EXG.L   A6,\1             ;put execbase in A6
              JSR     _LVOPermit(A6)    ;no registers touched.  A6=ExecBase
              EXG.L   A6,\1
              MEXIT
            ENDC
            IFNC    '\1',''             ;Case 2: save/restore A6
              MOVE.L  A6,-(SP)
              MOVE.L  4,A6
              JSR     _LVOPermit(A6)
              MOVE.L  (SP)+,A6
              MEXIT
            ENDC
            ENDM

        ENDC    ; EXEC_ABLES_I