1 files changed, 69 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/math/floorl.asm b/src/VBox/Runtime/common/math/floorl.asm
new file mode 100644
index 00000000..42af21a5
--- /dev/null
+++ b/src/VBox/Runtime/common/math/floorl.asm
@@ -0,0 +1,69 @@
+; $Id: floorl.asm $
+;; @file
+; IPRT - No-CRT floorl - 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
+;
+
+%include "iprt/asmdefs.mac"
+
+BEGINCODE
+
+;;
+; Compute the largest integral value not greater than lrd.
+; @returns st(0)
+; @param    lrd     [rbp + 8]
+RT_NOCRT_BEGINPROC floorl
+    push    xBP
+    mov     xBP, xSP
+    sub     xSP, 10h
+
+    fld     tword [xBP + xCB*2]
+
+    ; Make it round down by modifying the fpu control word.
+    fstcw   [xBP - 10h]
+    mov     eax, [xBP - 10h]
+    or      eax, 00400h
+    and     eax, 0f7ffh
+    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(floorl)
+