103 lines
3.9 KiB
NASM
103 lines
3.9 KiB
NASM
;*****************************************************************************
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;*
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;* Open Watcom Project
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;*
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;* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
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;*
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;* ========================================================================
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;*
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;* This file contains Original Code and/or Modifications of Original
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;* Code as defined in and that are subject to the Sybase Open Watcom
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;* Public License version 1.0 (the 'License'). You may not use this file
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;* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
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;* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
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;* provided with the Original Code and Modifications, and is also
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;* available at www.sybase.com/developer/opensource.
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;*
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;* The Original Code and all software distributed under the License are
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;* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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;* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
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;* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
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;* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
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;* NON-INFRINGEMENT. Please see the License for the specific language
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;* governing rights and limitations under the License.
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;*
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;* ========================================================================
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;*
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;* Description: Connect/disconnect 80x87 interrupt handler.
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;*
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;*****************************************************************************
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.8087
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.386p
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include struct.inc
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include mdef.inc
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xref __FPE2Handler_
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modstart fpe387
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datasegment
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Save87 dd 0
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enddata
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xdefp "C",__Init_FPE_handler
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defp __Init_FPE_handler
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_guess ; guess initialization required
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cmp dword ptr Save87,0 ; - quit if already initialized
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_quif ne ; - ...
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_admit ; admit: already initialized
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ret ; - return
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_endguess ; endguess
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push EAX ; save registers
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push EBX ; ...
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push ECX ; ...
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mov EAX, 68
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mov EBX, 15
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lea ECX, __FPE2Handler_
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int 40h ; set new #FPE handler
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mov Save87, EAX ; save old handler
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pop ECX ; ...
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pop EBX ; ...
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pop EAX ; ...
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ret ; return
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endproc __Init_FPE_handler
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xdefp "C",__Fini_FPE_handler
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defp __Fini_FPE_handler
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cmp dword ptr Save87,0 ; if not initialized
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_if e ; - then
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ret ; - return
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_endif ; endif
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push EAX ; save registers
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push EBX ; ...
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push EDX ; ...
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sub ESP,4 ; allocate space for control word
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fstcw word ptr [ESP] ; get control word
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fwait ; ...
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mov byte ptr [ESP],7Fh ; disable exception interrupts
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fldcw word ptr [ESP] ; ...
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fwait ; ...
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add ESP,4 ; remove temporary
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mov EAX, 68
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mov EBX, 15
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mov ECX, dword ptr Save87
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int 40h ; set new #FPE handler
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pop EDX ; ...
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pop EBX ; ...
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pop EAX ; ...
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ret
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endproc __Fini_FPE_handler
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endmod
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end
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