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; $Id: truncl.asm $
;; @file
; IPRT - No-CRT truncl - AMD64 & X86.
;
;
; 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.
;
; 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
;
%define RT_ASM_WITH_SEH64
%include "iprt/asmdefs.mac"
%include "iprt/x86.mac"
BEGINCODE
;;
; Round to truncated integer value.
; @returns st(0)
; @param lrd [rbp + 8]
RT_NOCRT_BEGINPROC truncl
push xBP
SEH64_PUSH_xBP
mov xBP, xSP
SEH64_SET_FRAME_xBP 0
sub xSP, 10h
SEH64_ALLOCATE_STACK 10h
SEH64_END_PROLOGUE
fld tword [xBP + xCB*2]
; Make it truncate up by modifying the fpu control word.
fstcw [xBP - 10h]
mov eax, [xBP - 10h]
or eax, X86_FCW_RC_ZERO ; both bits set, so no need to clear anything first.
mov [xBP - 08h], eax
fldcw [xBP - 08h]
; Round ST(0) to integer.
frndint
; Restore the fpu control word.
fldcw [xBP - 10h]
leave
ret
ENDPROC RT_NOCRT(truncl)
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