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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 03:01:46 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 03:01:46 +0000
commitf8fe689a81f906d1b91bb3220acde2a4ecb14c5b (patch)
tree26484e9d7e2c67806c2d1760196ff01aaa858e8c /src/VBox/Runtime/common/math/watcom/U8RS-x86-32.asm
parentInitial commit. (diff)
downloadvirtualbox-upstream.tar.xz
virtualbox-upstream.zip
Adding upstream version 6.0.4-dfsg.upstream/6.0.4-dfsgupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/VBox/Runtime/common/math/watcom/U8RS-x86-32.asm')
-rw-r--r--src/VBox/Runtime/common/math/watcom/U8RS-x86-32.asm63
1 files changed, 63 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/math/watcom/U8RS-x86-32.asm b/src/VBox/Runtime/common/math/watcom/U8RS-x86-32.asm
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+; $Id: U8RS-x86-32.asm $
+;; @file
+; BS3Kit - 32-bit Watcom C/C++, 64-bit unsigned integer right shift.
+;
+
+;
+; Copyright (C) 2007-2019 Oracle Corporation
+;
+; This file is part of VirtualBox Open Source Edition (OSE), as
+; available from http://www.virtualbox.org. This file is free software;
+; you can redistribute it and/or modify it under the terms of the GNU
+; General Public License (GPL) as published by the Free Software
+; Foundation, in version 2 as it comes in the "COPYING" file of the
+; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+; VirtualBox OSE 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.
+;
+
+%include "iprt/asmdefs.mac"
+
+
+BEGINCODE
+
+
+;;
+; 64-bit unsigned integer right shift.
+;
+; @returns EDX:EAX
+; @param EDX:EAX Value to shift.
+; @param BL Shift count (it's specified as ECX:EBX, but we only use BL).
+;
+global __U8RS
+__U8RS:
+ push ecx ; We're allowed to trash ECX, but why bother.
+
+ mov cl, bl
+ and cl, 3fh
+ test cl, 20h
+ jnz .big_shift
+
+ ; Shifting less than 32.
+ shrd eax, edx, cl
+ shr edx, cl
+
+.return:
+ pop ecx
+ ret
+
+.big_shift:
+ ; Shifting 32 or more.
+ mov eax, edx
+ shr eax, cl ; Only uses lower 5 bits.
+ xor edx, edx
+ jmp .return
+