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/ASMBitLastSetU64.asm | 130 +++++++++++++++++++++++ 1 file changed, 130 insertions(+) create mode 100644 src/VBox/Runtime/common/asm/ASMBitLastSetU64.asm (limited to 'src/VBox/Runtime/common/asm/ASMBitLastSetU64.asm') diff --git a/src/VBox/Runtime/common/asm/ASMBitLastSetU64.asm b/src/VBox/Runtime/common/asm/ASMBitLastSetU64.asm new file mode 100644 index 00000000..2d6cb38e --- /dev/null +++ b/src/VBox/Runtime/common/asm/ASMBitLastSetU64.asm @@ -0,0 +1,130 @@ +; $Id: ASMBitLastSetU64.asm $ +;; @file +; IPRT - ASMBitLastSetU64(). +; + +; +; 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 64-bit integer. +; +; Bits are numbered from 1 (least significant) to 64. +; +; @returns (xAX) index [1..64] of the last set bit. +; @returns (xAX) 0 if all bits are cleared. +; @param msc:rcx gcc:rdi x86:stack u64 Integer to search for set bits. +; +; @cproto DECLASM(unsigned) ASMBitLastSetU64(uint64_t u64); +; +RT_BEGINPROC ASMBitLastSetU64 +%if ARCH_BITS == 16 + CPU 8086 + push bp + mov bp, sp + + ; 63:48 + mov ax, 64 + mov cx, [bp + 2 + 2 + 6] + test cx, cx + jnz .next_bit + + ; 47:32 + mov al, 48 + or cx, [bp + 2 + 2 + 4] + jnz .next_bit + + ; 31:16 + mov al, 32 + or cx, [bp + 2 + 2 + 2] + jnz .next_bit + + ; 16:0 + mov al, 16 + or cx, [bp + 2 + 2 + 0] + jz .return_zero + + ; find the bit that was set. +.next_bit: + shl cx, 1 + jc .return + dec ax + jmp .next_bit + +.return_zero: + xor ax, ax +.return: + pop bp + ret + +%else + %if ARCH_BITS == 64 + %ifdef ASM_CALL64_GCC + bsr rax, rsi + %else + bsr rax, rcx + %endif + jz .return_zero + inc eax +.return: + ret + + %elif ARCH_BITS == 32 + ; Check the 2nd dword then the first one. + bsr eax, dword [esp + 4 + 4] + jz .check_1st_dword + add eax, 32 + ret + +.check_1st_dword: + bsr eax, dword [esp + 4 + 0] + jz .return_zero + inc eax + ret + + %else + %error "Missing or invalid ARCH_BITS." + %endif + +.return_zero: + xor eax, eax + ret +%endif +ENDPROC ASMBitLastSetU64 + -- cgit v1.2.3