diff options
Diffstat (limited to 'src/VBox/Runtime/common/math/watcom/U8LS-x86-32.asm')
-rw-r--r-- | src/VBox/Runtime/common/math/watcom/U8LS-x86-32.asm | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/math/watcom/U8LS-x86-32.asm b/src/VBox/Runtime/common/math/watcom/U8LS-x86-32.asm new file mode 100644 index 00000000..7021b33e --- /dev/null +++ b/src/VBox/Runtime/common/math/watcom/U8LS-x86-32.asm @@ -0,0 +1,64 @@ +; $Id: U8LS-x86-32.asm $ +;; @file +; BS3Kit - 32-bit Watcom C/C++, 64-bit integer left 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 integer left 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 __U8LS +__U8LS: +global __I8LS +__I8LS: + 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. + shld edx, eax, cl + shl eax, cl + +.return: + pop ecx + ret + +.big_shift: + ; Shifting 32 or more. + mov edx, eax + shl edx, cl ; Only uses lower 5 bits. + xor eax, eax + jmp .return + |