1 files changed, 89 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..d9533c57
--- /dev/null
+++ b/src/VBox/Runtime/common/string/RTStrMemFind32.asm
@@ -0,0 +1,89 @@
+; $Id: RTStrMemFind32.asm $
+;; @file
+; IPRT - RTStrMemFind32 - AMD64 & X86.
+;
+
+;
+; Copyright (C) 2019-2020 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
+
+;;
+;
+; 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
+BEGINPROC_EXPORTED 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
+