; $Id: ASMGetXcr0.asm $
;; @file
; IPRT - ASMGetXcr0().
;

;
; Copyright (C) 2006-2023 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.
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; You should have received a copy of the GNU General Public License
; along with this program; if not, see <https://www.gnu.org/licenses>.
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; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
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;*******************************************************************************
;* Header Files                                                                *
;*******************************************************************************
%define RT_ASM_WITH_SEH64
%include "iprt/asmdefs.mac"

BEGINCODE

;;
; Gets the content of the XCR0 CPU register.
; @returns XCR0 value in rax (amd64) / edx:eax (x86).
;
RT_BEGINPROC ASMGetXcr0
SEH64_END_PROLOGUE
        xor     ecx, ecx                ; XCR0
        xgetbv
%ifdef RT_ARCH_AMD64
        shl     rdx, 32
        or      rax, rdx
%endif
%if ARCH_BITS == 16 ; DX:CX:BX:AX - DX=15:0, CX=31:16, BX=47:32, AX=63:48
        mov     ebx, edx
        mov     ecx, eax
        shr     ecx, 16
        xchg    eax, edx
        shr     eax, 16
%endif
        ret
ENDPROC ASMGetXcr0