From f215e02bf85f68d3a6106c2a1f4f7f063f819064 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:17:27 +0200 Subject: Adding upstream version 7.0.14-dfsg. Signed-off-by: Daniel Baumann --- src/VBox/Runtime/common/asm/ASMBitLastSetU16.asm | 101 +++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 src/VBox/Runtime/common/asm/ASMBitLastSetU16.asm (limited to 'src/VBox/Runtime/common/asm/ASMBitLastSetU16.asm') diff --git a/src/VBox/Runtime/common/asm/ASMBitLastSetU16.asm b/src/VBox/Runtime/common/asm/ASMBitLastSetU16.asm new file mode 100644 index 00000000..446e1fb5 --- /dev/null +++ b/src/VBox/Runtime/common/asm/ASMBitLastSetU16.asm @@ -0,0 +1,101 @@ +; $Id: ASMBitLastSetU16.asm $ +;; @file +; IPRT - ASMBitLastSetU16(). +; + +; +; 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 . +; +; 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 +; + + +;******************************************************************************* +;* Header Files * +;******************************************************************************* +%include "iprt/asmdefs.mac" + +BEGINCODE + +;; +; Finds the last bit which is set in the given 16-bit integer. +; +; Bits are numbered from 1 (least significant) to 16. +; +; @returns (xAX) index [1..16] of the last set bit. +; @returns (xAX) 0 if all bits are cleared. +; @param msc:cx gcc:di x86:stack u16 Integer to search for set bits. +; +; @cproto DECLASM(unsigned) ASMBitLastSetU16(uint32_t u16); +; +RT_BEGINPROC ASMBitLastSetU16 +%if ARCH_BITS == 16 + CPU 8086 + push bp + mov bp, sp + + mov cx, [bp + 2 + 2] + test cx, cx ; check if zero (eliminates checking dec ax result) + jz .return_zero + + mov ax, 16 +.next_bit: + shl cx, 1 + jc .return + dec ax + jmp .next_bit + +.return_zero: + xor ax, ax +.return: + pop bp + ret + +%else + xor eax, eax + %if ARCH_BITS == 64 + %ifdef ASM_CALL64_GCC + bsr ax, si + %else + bsr ax, cx + %endif + %elif ARCH_BITS == 32 + bsr ax, word [esp + 4] + %else + %error "Missing or invalid ARCH_BITS." + %endif + jz .return_zero + inc eax +.return: + ret +.return_zero: + xor eax, eax + ret +%endif +ENDPROC ASMBitLastSetU16 + -- cgit v1.2.3