1 files changed, 76 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/math/truncl.asm b/src/VBox/Runtime/common/math/truncl.asm
new file mode 100644
index 00000000..579493de
--- /dev/null
+++ b/src/VBox/Runtime/common/math/truncl.asm
@@ -0,0 +1,76 @@
+; $Id: truncl.asm $
+;; @file
+; IPRT - No-CRT truncl - AMD64 & X86.
+;
+
+;
+; Copyright (C) 2006-2022 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)
+