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;**************************************************************************
; arch/z80/src/ez80/ez80_irqsave.asm
;
; Copyright (C) 2008 Gregory Nutt. All rights reserved.
; Author: Gregory Nutt <gnutt@nuttx.org>
;
; Redistribution and use in source and binary forms, with or without
; modification, are permitted provided that the following conditions
; are met:
;
; 1. Redistributions of source code must retain the above copyright
; notice, this list of conditions and the following disclaimer.
; 2. Redistributions in binary form must reproduce the above copyright
; notice, this list of conditions and the following disclaimer in
; the documentation and/or other materials provided with the
; distribution.
; 3. Neither the name NuttX nor the names of its contributors may be
; used to endorse or promote products derived from this software
; without specific prior written permission.
;
; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
; FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
; COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
; BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
; OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
; AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
; LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
; ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
; POSSIBILITY OF SUCH DAMAGE.
;
;**************************************************************************
;**************************************************************************
; Global Symbols Imported
;**************************************************************************
;**************************************************************************
; Global Symbols Expported
;**************************************************************************
xdef _irqsave
xdef _irqrestore
;**************************************************************************
; Code
;**************************************************************************
segment CODE
.assume ADL=1
;**************************************************************************
;* Name: irqstate_t irqsave(void)
;*
;* Description:
;* Disable all interrupts; return previous interrupt state
;*
;**************************************************************************
_irqsave:
ld a, i ; AF = interrupt state
di ; Interrupts are disabled (does not affect F)
push af ; Transfer to HL via the stack
pop hl ;
ret ; And return
;**************************************************************************
;* Name: void irqrestore(irqstate_t flags)
;*
;* Description:
;* Restore previous interrupt state
;*
;**************************************************************************
_irqrestore:
di ; Assume disabled
pop hl ; HL = return address
pop af ; AF Parity bit holds interrupt state
jp po, _disabled ; Skip over re-enable if Parity odd
ei ; Re-enable interrupts
_disabled:
push af ; Restore stack
push hl ;
ret ; and return
end
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