1 files changed, 127 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/string/bzero.asm b/src/VBox/Runtime/common/string/bzero.asm
new file mode 100644
index 00000000..75423ee5
--- /dev/null
+++ b/src/VBox/Runtime/common/string/bzero.asm
@@ -0,0 +1,127 @@
+; $Id: bzero.asm $
+;; @file
+; IPRT - No-CRT bzero - AMD64 & X86.
+;
+
+;
+; Copyright (C) 2006-2019 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
+
+;;
+; @param    pvDst   gcc: rdi  msc: rcx  x86:[esp+4]  wcall:eax
+; @param    cb      gcc: rsi  msc: rdx  x86:[esp+8]  wcall:edx
+RT_NOCRT_BEGINPROC bzero
+%ifdef RT_OS_DARWIN
+GLOBALNAME __bzero
+%endif
+        cld
+%ifdef RT_ARCH_AMD64
+        xor     eax, eax
+ %ifdef ASM_CALL64_MSC
+        mov     r9, rdi                 ; save rdi in r9
+        mov     rdi, rcx
+
+        ; todo: alignment?
+        mov     rcx, rdx
+        shr     rcx, 3
+        rep stosq
+
+        and     rdx, 7
+        mov     rcx, rdx
+        rep stosb
+
+        mov     rdi, r9                 ; restore rdi
+
+ %else ; GCC
+        ; todo: alignment?
+        mov     rcx, rsi
+        shr     rcx, 3
+        rep stosq
+
+        and     rsi, 7
+        mov     rcx, rsi
+        rep stosb
+
+ %endif ; GCC
+
+%elif ARCH_BITS == 32
+        push    ebp
+        mov     ebp, esp
+        push    edi
+
+ %ifdef ASM_CALL32_WATCOM
+        mov     ecx, edx
+        mov     edi, eax
+ %else
+        mov     ecx, [ebp + 0ch]
+        mov     edi, [ebp + 08h]
+ %endif
+        xor     eax, eax
+
+        mov     edx, ecx
+        shr     ecx, 2
+        rep stosd
+
+        and     edx, 3
+        mov     ecx, edx
+        rep stosb
+
+        pop     edi
+        leave
+
+%elif ARCH_BITS == 16
+        push    bp
+        mov     bp, sp
+        push    di
+
+        mov     cx, [bp + 0ch]
+        mov     di, [bp + 08h]
+        xor     ax, ax
+
+        ; align di.
+        test    di, 1
+        jz      .aligned
+        jcxz    .done
+        stosb
+        dec     cx
+        jz      .done
+
+.aligned:
+        mov     dx, cx
+        shr     cx, 1
+        rep stosw
+
+        test    dl, 1
+        jz      .done
+        stosb
+
+.done:
+        pop     di
+        pop     bp
+%else
+ %error ARCH_BITS
+%endif ; X86
+        ret
+ENDPROC RT_NOCRT(bzero)
+