; $Id: x86-allshr.asm 106061 2024-09-16 14:03:52Z vboxsync $
;; @file
; IPRT - Visual C++ Compiler - signed 64-bit right shift support, x86.
;

;
; Copyright (C) 2023-2024 Oracle and/or its affiliates.
;
; This file is part of VirtualBox base platform packages, as
; available from https://www.virtualbox.org.
;
; This program is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public License
; as published by the Free Software Foundation, in version 3 of the
; License.
;
; This program is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
; General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, see <https://www.gnu.org/licenses>.
;
; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
; in the VirtualBox distribution, in which case the provisions of the
; CDDL are applicable instead of those of the GPL.
;
; You may elect to license modified versions of this file under the
; terms and conditions of either the GPL or the CDDL or both.
;
; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
;


;*********************************************************************************************************************************
;*  Header Files                                                                                                                 *
;*********************************************************************************************************************************
%include "iprt/asmdefs.mac"


;;
; Right-shift signed 64-bit value.
;
; @returns  edx:eax
; @param    edx:eax Value to shift.
; @param    cl      Shift count.
; @uses     cl
;
BEGINPROC_RAW   __allshr
        test    cl, ~31
        jnz     .shift_32_or_more

        shrd    eax, edx, cl
        sar     edx, cl
        ret

.shift_32_or_more:
        mov     eax, edx
        sar     edx, 31                     ; sign bit propagation to all of edx (-> 0 or 0xffffffff).

        test    cl, ~63
        jnz     .shift_64_or_more

        and     cl, 31
        sar     eax, cl
        ret

.shift_64_or_more:
        mov     eax, edx
        ret
ENDPROC_RAW     __allshr

