1 files changed, 99 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/string/RTStrMemFind32.asm b/src/VBox/Runtime/common/string/RTStrMemFind32.asm
new file mode 100644
index 00000000..55cb202e
--- /dev/null
+++ b/src/VBox/Runtime/common/string/RTStrMemFind32.asm
@@ -0,0 +1,99 @@
+; $Id: RTStrMemFind32.asm $
+;; @file
+; IPRT - RTStrMemFind32 - AMD64 & X86.
+;
+
+;
+; Copyright (C) 2019-2023 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
+
+;;
+;
+; This is just a 32-bit memchr.
+;
+; @param    pvHaystack      gcc: rdi  msc: ecx  x86:[esp+4]   wcall: eax
+; @param    uNeedle         gcc: esi  msc: edx  x86:[esp+8]   wcall: edx
+; @param    cbHaystack      gcc: rdx  msc: r8   x86:[esp+0ch] wcall: ebx
+RT_BEGINPROC RTStrMemFind32
+        cld
+%ifdef RT_ARCH_AMD64
+ %ifdef ASM_CALL64_MSC
+        mov     r9, rdi                 ; save rdi
+        mov     eax, edx
+        mov     rdi, rcx
+        mov     rcx, r8
+ %else
+        mov     rcx, rdx
+        mov     eax, esi
+ %endif
+%else
+ %ifdef ASM_CALL32_WATCOM
+        mov     ecx, ebx
+        xchg    eax, edx
+        xchg    edi, edx                ; load and save edi.
+ %else
+        mov     ecx, [esp + 0ch]
+        mov     edx, edi                ; save edi
+        mov     eax, [esp + 8]
+        mov     edi, [esp + 4]
+ %endif
+%endif
+        cmp     xCX, 4
+        jb      .not_found
+
+        ; do the search
+        repne   scasd
+        jne     .not_found
+
+        ; found it
+        lea     xAX, [xDI - 4]
+%ifdef ASM_CALL64_MSC
+        mov     rdi, r9
+%endif
+%ifdef RT_ARCH_X86
+        mov     edi, edx
+%endif
+        ret
+
+.not_found:
+%ifdef ASM_CALL64_MSC
+        mov     rdi, r9
+%endif
+%ifdef RT_ARCH_X86
+        mov     edi, edx
+%endif
+        xor     eax, eax
+        ret
+ENDPROC RTStrMemFind32
+