93cc62b645
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@748 42af7a65-404d-4744-a932-0658087f49c3
89 lines
3.3 KiB
NASM
89 lines
3.3 KiB
NASM
;**************************************************************************
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; arch/z80/src/ez80/ez80_irqsave.asm
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;
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; Copyright (C) 2008 Gregory Nutt. All rights reserved.
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; Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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;
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; Redistribution and use in source and binary forms, with or without
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; modification, are permitted provided that the following conditions
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; are met:
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;
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; 1. Redistributions of source code must retain the above copyright
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; notice, this list of conditions and the following disclaimer.
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; 2. Redistributions in binary form must reproduce the above copyright
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; notice, this list of conditions and the following disclaimer in
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; the documentation and/or other materials provided with the
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; distribution.
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; 3. Neither the name NuttX nor the names of its contributors may be
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; used to endorse or promote products derived from this software
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; without specific prior written permission.
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;
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; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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; FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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; COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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; BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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; OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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; AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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; LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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; ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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; POSSIBILITY OF SUCH DAMAGE.
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;
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;**************************************************************************
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;**************************************************************************
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; Global Symbols Imported
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;**************************************************************************
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;**************************************************************************
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; Global Symbols Expported
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;**************************************************************************
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xdef _irqsave
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xdef _irqrestore
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;**************************************************************************
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; Code
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;**************************************************************************
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segment CODE
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.assume ADL=1
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;**************************************************************************
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;* Name: irqstate_t irqsave(void)
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;*
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;* Description:
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;* Disable all interrupts; return previous interrupt state
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;*
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;**************************************************************************
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_irqsave:
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ld a, i ; AF = interrupt state
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di ; Interrupts are disabled (does not affect F)
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push af ; Transfer to HL via the stack
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pop hl ;
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ret ; And return
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;**************************************************************************
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;* Name: void irqrestore(irqstate_t flags)
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;*
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;* Description:
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;* Restore previous interrupt state
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;*
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;**************************************************************************
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_irqrestore:
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di ; Assume disabled
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pop hl ; HL = return address
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pop af ; AF Parity bit holds interrupt state
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jp po, _disabled ; Skip over re-enable if Parity odd
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ei ; Re-enable interrupts
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_disabled:
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push af ; Restore stack
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push hl ;
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ret ; and return
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end
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