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553 serge 1 
;*****************************************************************************
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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:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
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;*               DESCRIBE IT HERE!
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;*
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;*****************************************************************************
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include mdef.inc
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include struct.inc
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;========================================================================
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;==     Name:           I8S                                            ==
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;==     Operation:      integer eight byte shift                       ==
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;==     Inputs:         EDX;EAX   integer M1                           ==
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;==                     ECX;EBX   integer M2  (ECX contents ignored)   ==
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;==     Outputs:        EDX;EAX   product                              ==
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;==     Volatile:       ECX, EBX destroyed                             ==
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;========================================================================
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; Special Note:
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; If ECX ever takes on a meaningful use (i.e., is no longer ignored)
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; then several routines that call these shift routines will require fixing.
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; At present, the following routines ignore what is in ECX.
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        modstart        i8s
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        xdefp   __U8RS
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        defpe   __U8RS
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        mov     ecx,ebx         ; get shift-count into cl
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        and     cl,03fH         ; get mod 64 shift count
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        test    cl,020H         ; see if count >= 32
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        jnz     L1
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        shrd    eax,edx,cl
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        shr     edx,cl
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        ret                     ; and return!!!
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L1:
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        mov     eax,edx
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        sub     ecx,020H        ; knock off 32-bits of shifting
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        xor     edx,edx         ; zero extend result
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        shr     eax,cl
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        ret
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        endproc __U8RS
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        xdefp   __I8RS
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        defpe   __I8RS
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        mov     ecx,ebx         ; get shift-count into cl
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        and     cl,03fH         ; get mod 64 shift count
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        test    cl,020H         ; see if count >= 32
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        jnz     L2
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        shrd    eax,edx,cl
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        sar     edx,cl
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        ret                     ; and return!!!
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L2:
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        mov     eax,edx         ; shift hi into lo (1st 32 bits now shifted)
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        sub     cl,020H         ; knock off 32-bits of shifting
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        sar     edx,31          ; sign extend hi-word
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        sar     eax,cl          ; shift remaining part
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        ret
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        endproc __I8RS
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        xdefp   __I8LS
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        xdefp   __U8LS
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        defpe   __I8LS
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        defpe   __U8LS
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        mov     ecx,ebx         ; get shift-count into cl
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        and     cl,03fH         ; get mod 64 shift count
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        test    cl,020H         ; see if count >= 32
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        jnz     L3
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        shld    edx,eax,cl
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        shl     eax,cl
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        ret                     ; and return!!!
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L3:
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        mov     edx,eax         ; shift lo into hi (1st 32 bits now shifted)
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        sub     cl,020H         ; knock off 32-bits of shifting
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        xor     eax,eax         ; lo 32 bits are now zero
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        shl     edx,cl          ; shift remaining part
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        ret                     ; and return!!!
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        endproc __U8LS
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        endproc __I8LS
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        endmod
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        end