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Diffstat (limited to '')
-rw-r--r-- | src/VBox/ValidationKit/bootsectors/bs3kit/bs3-wc16-U8RS.asm | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-wc16-U8RS.asm b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-wc16-U8RS.asm new file mode 100644 index 00000000..4da920d7 --- /dev/null +++ b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-wc16-U8RS.asm @@ -0,0 +1,82 @@ +; $Id: bs3-wc16-U8RS.asm $ +;; @file +; BS3Kit - 16-bit Watcom C/C++, 64-bit unsigned integer right shift. +; + +; +; Copyright (C) 2007-2023 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 "bs3kit-template-header.mac" + + +;; +; 64-bit unsigned integer left shift. +; +; @returns AX:BX:CX:DX (AX is the most significant, DX the least) +; @param AX:BX:CX:DX Value to shift. +; @param SI Shift count. +; +%ifdef BS3KIT_WITH_REAL_WATCOM_INTRINSIC_NAMES +global __U8RS +__U8RS: +%endif +global $_?U8RS +$_?U8RS: + push si + + ; + ; The 16-bit watcom code differs from the 32-bit one in the way it + ; handles the shift count. All 16-bit bits are used in the 16-bit + ; code, we do the same as the 32-bit one as we don't want to wast + ; time in the below loop. + ; + ; Using 8086 comatible approach here as it's less hazzle to write + ; and smaller. + ; + and si, 3fh + jz .return + +.next_shift: + shr ax, 1 + rcr bx, 1 + rcr cx, 1 + rcr dx, 1 + dec si + jnz .next_shift + +.return: + pop si +%ifdef ASM_MODEL_FAR_CODE + retf +%else + ret +%endif + |