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|
; $Id: memrchr.asm $
;; @file
; IPRT - No-CRT memrchr - AMD64 & X86.
;
;
; 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 <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 "iprt/asmdefs.mac"
BEGINCODE
;;
; @param pv gcc: rdi msc: ecx x86:[esp+4] wcall: eax
; @param ch gcc: esi msc: edx x86:[esp+8] wcall: edx
; @param cb gcc: rdx msc: r8 x86:[esp+0ch] wcall: ebx
RT_NOCRT_BEGINPROC memrchr
std
%ifdef RT_ARCH_AMD64
%ifdef ASM_CALL64_MSC
or r8, r8
jz .not_found_early
mov r9, rdi ; save rdi
mov eax, edx
lea rdi, [rcx + r8 - 1]
mov rcx, r8
%else
mov rcx, rdx
jrcxz .not_found_early
mov eax, esi
lea rdi, [rdi + rcx - 1]
%endif
%else
%ifdef ASM_CALL32_WATCOM
mov ecx, ebx
jecxz .not_found_early
xchg eax, edx
xchg edi, edx ; load + save edi
%else
mov ecx, [esp + 0ch]
jecxz .not_found_early
mov edx, edi ; save edi
mov eax, [esp + 8]
mov edi, [esp + 4]
%endif
lea edi, [edi + ecx - 1]
%endif
; do the search
repne scasb
jne .not_found
; found it
lea xAX, [xDI + 1]
%ifdef ASM_CALL64_MSC
mov rdi, r9
%endif
%ifdef RT_ARCH_X86
mov edi, edx
%endif
cld
ret
.not_found:
%ifdef ASM_CALL64_MSC
mov rdi, r9
%endif
%ifdef RT_ARCH_X86
mov edi, edx
%endif
.not_found_early:
xor eax, eax
cld
ret
ENDPROC RT_NOCRT(memrchr)
|
