119 lines
4.3 KiB
NASM
119 lines
4.3 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: 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
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