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kolibrios/programs/develop/open watcom/trunk/clib/fpu/fpe387.asm

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;*****************************************************************************
;*
;* Open Watcom Project
;*
;* Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
;*
;* ========================================================================
;*
;* This file contains Original Code and/or Modifications of Original
;* Code as defined in and that are subject to the Sybase Open Watcom
;* Public License version 1.0 (the 'License'). You may not use this file
;* except in compliance with the License. BY USING THIS FILE YOU AGREE TO
;* ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
;* provided with the Original Code and Modifications, and is also
;* available at www.sybase.com/developer/opensource.
;*
;* The Original Code and all software distributed under the License are
;* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
;* EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
;* ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
;* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
;* NON-INFRINGEMENT. Please see the License for the specific language
;* governing rights and limitations under the License.
;*
;* ========================================================================
;*
;* Description: Connect/disconnect 80x87 interrupt handler.
;*
;*****************************************************************************
.8087
.386p
include struct.inc
include mdef.inc
xref __FPE2Handler_
modstart fpe387
datasegment
Save87 dd 0
OldMask dd 0
enddata
xdefp "C",__Init_FPE_handler
defp __Init_FPE_handler
_guess ; guess initialization required
cmp dword ptr Save87,0 ; - quit if already initialized
_quif ne ; - ...
_admit ; admit: already initialized
ret ; - return
_endguess ; endguess
push EAX ; save registers
push EBX ; ...
push ECX ; ...
push EDX ; ...
mov EAX, 68
mov EBX, 24
mov EDX, 10000h ; 1 shl 16 - #MF
lea ECX, __FPE2Handler_
int 40h ; set new exception handler
mov Save87, EAX ; save old handler
mov OldMask,EBX ; save old mask
pop EDX ; ...
pop ECX ; ...
pop EBX ; ...
pop EAX ; ...
ret ; return
endproc __Init_FPE_handler
xdefp "C",__Fini_FPE_handler
defp __Fini_FPE_handler
cmp dword ptr Save87,0 ; if not initialized
_if e ; - then
ret ; - return
_endif ; endif
push EAX ; save registers
push EBX ; ...
; ECX ????
push EDX ; ...
sub ESP,4 ; allocate space for control word
fstcw word ptr [ESP] ; get control word
fwait ; ...
mov byte ptr [ESP],7Fh ; disable exception interrupts
fldcw word ptr [ESP] ; ...
fwait ; ...
add ESP,4 ; remove temporary
mov EAX, 68
mov EBX, 24
mov ECX, dword ptr Save87 ; restore handler
mov EDX, dword ptr OldMask ; restore mask
int 40h ; set new ecxeption handler
pop EDX ; ...
; ECX ????
pop EBX ; ...
pop EAX ; ...
ret
endproc __Fini_FPE_handler
endmod
end